Bovine peritonitis associated with Mannheimia haemolytica serotype 2 in a three-day-old Japanese Black calf

Inhibitory Effect of Puerarin on Lipopolysaccharide-triggered Inflammatory Responses of Bovine Kidney Cells

Puerarin (Pue), a flavonoid compound, possesses cytoprotective effects and LPS has been reported to induce renal inflammatory injury in bovine. However, whether Pue inhibits lipopolysaccharide (LPS)-induced inflammatory damage of bovine kidney cells remains unknown. Based on an in vitro model with Madin-Darby bovine kidney (MDBK) cell line, it has found that Pue attenuated LPS-induced damage of MDBK cells, as evidenced by cell viability and lactic dehydrogenase (LDH) release rescued by Pue (P < 0.05). Additionally, the real-time quantitative PCR (qPCR) and enzyme linked immunosorbent assay (ELISA) showed that LPS elevated the levels of pro-inflammatory factors interleukin (IL)-1β, IL-8 and tumor necrosis factor (TNF)-α, which was reversed by pretreatment of Pue (P < 0.05). Besides, Pue reduced the expression of Toll like receptor 4 (TLR4) and phosphorylated nuclear factor kappa B (p-NF-κB) of LPS-exposed MDBK cells (P < 0.05). Collectively, these results showed that Pue suppresses LPS-evoked inflammatory damage of bovine kidney cells, suggesting Pue a potential compound for intervention of bovine inflammation.

RAGE-TLR4 Crosstalk Is the Key Mechanism by Which High Glucose Enhances the Lipopolysaccharide-Induced Inflammatory Response in Primary Bovine Alveolar Macrophages

The receptor of advanced glycation end products (RAGE) and Toll-like receptor 4 (TLR4) are important receptors for inflammatory responses induced by high glucose (HG) and lipopolysaccharide (LPS) and show crosstalk phenomena in inflammatory responses. However, it is unknown whether RAGE and TLR4 can influence each other's expression through a crosstalk mechanism and whether the RAGE-TLR4 crosstalk related to the molecular mechanism of HG enhances the LPS-induced inflammatory response. In this study, the implications of LPS with multiple concentrations (0, 1, 5, and 10 μg/mL) at various treatment times (0, 3, 6, 12, and 24 h) in primary bovine alveolar macrophages (BAMs) were explored. The results showed that a 5 μg/mL LPS treatment at 12 h had the most significant increment on the pro-inflammatory cytokine interleukin 1β (IL-1β), IL-6, and tumor necrosis factor (TNF)-α levels in BAMs (p < 0.05) and that the levels of TLR4, RAGE, MyD88, and NF-κB p65 mRNA and protein expression were upregulated (p < 0.05). Then, the effect of LPS (5 μg/mL) and HG (25.5 mM) co-treatment in BAMs was explored. The results further showed that HG significantly enhanced the release of IL-1β, IL-6, and TNF-α caused by LPS in the supernatant (p < 0.01) and significantly increased the levels of RAGE, TLR4, MyD88, and NF-κB p65 mRNA and protein expression (p < 0.01). Pretreatment with FPS-ZM1 and TAK-242, the inhibitors of RAGE and TLR4, significantly alleviated the HG + LPS-induced increment of RAGE, TLR4, MyD88, and NF-κB p65 mRNA and protein expression in the presence of HG and LPS (p < 0.01). This study showed that RAGE and TLR4 affect each other's expression through crosstalk during the combined usage of HG and LPS and synergistically activate the MyD88/NF-κB signaling pathway to promote the release of pro-inflammatory cytokines in BAMs.

Distinct Mannheimia haemolytica serotypes isolated from fatal infections in veal calves and dairy cows

Fatal Mannheimia haemolytica (M. haemolytica) infections in cattle, which emerged in the Netherlands between 2004 and 2018, showed two distinct disease presentations: acute fibrinous polyserositis (FPS) in veal calves, and acute fibrinous pleuro-pneumonia (FPP) in adult dairy cattle. To determine whether these presentations were caused by different M. haemolytica genotypes, whole genome sequencing was performed on 96 isolates cultured after necropsy from inflamed sites of veal calves that died of M. haemolytica-associated FPS (n = 49) or with FPP lesions (n = 2), and from dairy cows that died of M. haemolytica-associated FPP (n = 45). Among the 96 M. haemolytica isolates, 93 were shown to belong to either of two large clusters, with 48/51 calf isolates belonging to one, and 43/45 cow isolates and two calf isolates from cases of FPP to the other. All M. haemolytica isolates from veal calves with FPS were of serotype A2, whereas the isolates from dairy cows and two calves with FPP were predominantly of serotypes A1 and A6. Most serotype A2 isolates from veal calves with FPS (95.6 %) contained multiple antibiotic resistance genes (ARGs) against three to five antimicrobial classes (phenicols, sulphonamides, tetracyclines, aminoglycosides or beta-lactams). In contrast, these ARGs were only present in 10.8 % of M. haemolytica A1 and A6 isolates from pneumonic adult cattle and absent in isolates from the two calves with FPP. These two disease presentations appear to be caused by genetically distinct strains with different antimicrobial resistance gene patterns. While M. haemolytica serotype A2 is generally considered to be a commensal microorganism of cattle, it was clearly associated with fatal FPS in veal calves in the Netherlands.

The combination of high glucose and LPS induces autophagy in bovine kidney epithelial cells via the Notch3/mTOR signaling pathway

BACKGROUND

Aside respiratory diseases, beef cattle may also suffer from serious kidney diseases after transportation. Hyperglycemia and gram-negative bacterial infection may be the main reasons why bovine is prone to severe kidney disease during transportation stress, however, the precise mechanism is still unclear. The purpose of the current study is to explore whether the combined treatment of high glucose (HG) and lipopolysaccharide (LPS) could induce madin-darby bovine kidney (MDBK) cells injury and autophagy, as well as investigate the potential molecular mechanisms involved.

RESULTS

As we discovered, the combined effect of HG and LPS decreased MDBK cells viability. And, HG and LPS combination also induced autophagy in MDBK cells, which was characterized by increasing the expression of LC3-II/I and Beclin1 and decreasing p62 expression. LC3 fluorescence signal formation was also significantly increased by HG and LPS combination treatment. Furthermore, we measured whether the mammalian target of rapamycin (mTOR) and the Notch3 signaling pathways were involved in HG and LPS-induced autophagy. The results showed that the combination of HG and LPS significantly increased the protein expression of Notch3 and decreased protein expression of p-mTOR, indicating that Notch3 and mTOR signaling pathways were activated. However, co-treatment with the Notch3 inhibitor (DAPT) could reverse the induction of autophagy, and increased the protein expression of p-mTOR.

CONCLUSIONS

This study demonstrated that the combination effect of HG and LPS could induce autophagy in MDBK cells, and the Notch3/mTOR signaling pathway was involved in HG and LPS-induced autophagy.

Phenotypic and genotypic characterization of Actinobacillus suis sensu stricto isolated from a dairy calf

The species of the genus Actinobacillus have so far been associated with specific animal hosts, and A. suis sensu stricto, an opportunistic pathogen of swine, is rarely isolated from ruminants. We describe here the isolation of A. suis sensu stricto from a newborn calf that died on a dairy farm in Japan. Identification of the isolate was performed by phenotypic and genotypic characterization, with the latter consisting of nucleotide sequence analyses of the 16S rRNA gene plus three housekeeping genes, rpoB, infB and recN.

Pyelonephritis caused by Mannheimia varigena in a Holstein calf

A 7-day-old calf died following development of mild respiratory symptoms. Postmortem examination revealed the kidneys were inflamed, and Gram-negative bacteria was detected in the kidneys, supporting the diagnosis of suppurative pyelonephritis. Mannheimia varigena antigen was found in the lesions and the cytoplasm of macrophages and neutrophils in the renal cortex. The Gram-negative bacilli from the kidney were identified as M. varigena by sequencing the 16S rDNA. Although M. varigena is known to cause bovine respiratory disease syndrome, shipping fever, and meningitis, it was unknown that it could also cause suppurative pyelonephritis. Our study provides the first evidence of suppurative pyelonephritis caused by M. varigena in cattle and information that would improve our understanding, diagnosis, and treatment for M. varigena infections.