Biology subjects

GERMON, P.

Publications and source records attributed to GERMON, P..

5 recordsLinked to original sources

bioRxiv2025

Nutritional supplementation with vitamin E or plant extracts affects redox and immune response in early lactating dairy cows

In dairy cows, early lactation is a period prone to oxidative stress, inflammation and health problems. Our objective was to investigate the effects of the nutritional supplementation of early lactating cows with plant extracts or vitamin E on physiological and immunological status. Forty-five Holstein cows were divided into three groups: control group (n = 15), vitamin E group (n = 16) (3,000 IU/d for 3 weeks before and 1,000 IU/d after calving), and plant extract group (n = 14) (10 g/d only after calving). Their redox and immune status were monitored during the first 12 weeks of lactation, every four week. In week 12, plasma malondialdehyde levels in plasma were lower in the vitamin E and plant extract groups than in the control group. The vitamin E and plant extract groups had lower ex vivo plasma CCL4, IL6 and IL8 cytokine levels, lower proportions of blood regulatory neutrophils, and less ROS production by blood neutrophils than the control group. In terms of immune response, vitamin E and plant extracts down-regulated the gene expression of FABP3 in the milk mammary epithelial cells of multiparous cows. Therefore, supplementation with either vitamin E or plant extracts could prevent systemic hyper-inflammation and improve the immune response during early lactation.

physiology↗

bioRxiv2025

Nutritional vitamin E or plant extracts affect the immune response and mammary epithelium integrity during intramammary lipopolysaccharide challenge in early lactation

BackgroundEarly lactation is a period at risk for mastitis. Our objective was to investigate the influence of nutritional vitamin E and plant extracts on redox and immune status at the systemic and local mammary levels during an inflammatory challenge in dairy cows. Thirty-six Holstein cows were placed in three groups: a control group (n = 11) unsupplemented; a vitamin E group (n = 13), supplemented with 3000 IU/d for 4 weeks before calving and 1000 IU/d for 4 weeks after calving; and a plant extracts group (n = 14) supplemented with 10 g/d for 4 weeks before and after calving. Lipopolysaccharide (LPS) from Escherichia coli was infused into a one-udder quarter of the cows 5 weeks after calving. Blood and milk samples were collected before and 4, 7, 9, 28, and 76 h after the LPS infusion. ResultsIn the plant extract group, antioxidant gene (NQO1), superoxide dismutase activity 4 hours after the LPS challenge and total antioxidant capacity were increased compared to the control group. In the vitamin E group, expression of the antioxidant gene (SOD3) and glutathione peroxidase activity were more elevated than in the control group. Systemic immunity appeared to be reduced by antioxidant supplementations, with a higher migration of classical neutrophils in the plant extract group and less ROS production of neutrophils in the vitamin E group. However, immune capacities were increased at the local level in classical neutrophils (ROS production and phagocytosis) in both the plant extract and vitamin E groups. Following the LPS infusion, supplementation did not reveal any differences in terms of rectal temperature, milk yield or milk cell counts, but it did have a positive effect on mammary epithelium integrity (lower milk Na+:K+ ratio and higher OCLN gene expression). In addition, the plant extracts stimulated the synthesis of milk constituents, with higher milk protein gene expressions (LALBA, CSN3, CSN1S1) and a tendency towards a higher lactose content in milk. ConclusionThe LPS challenge showed that vitamin E or plant extracts enhanced the local inflammatory response while preserving systemic antioxidant capacities, integrity of the mammary gland and the composition of milk, and thus possibly contributing to preventing mammary infection in early lactating dairy cows.

physiology↗

bioRxiv2025

Gene expression profiling of bovine raw milk is linked to the inflammatory status of the udder

Inflammation of the mammary gland, or mastitis, is a common disease of dairy cows with important consequences on the economy of dairy farms, well-being of cows and antibiotic usage. Monitoring of the inflammatory status of mammary gland currently relies on milk somatic cell counting. In order to improve this monitoring, methods aiming at differentiating cell types among milk cells are being developed. The objective of the present study was to explore the use of gene expression profiling from raw milk samples to define the inflammatory status of udder quarters. A pilot study allowed us to select 37 genes differentially expressed between three milk cell types, i.e. neutrophils, macrophages or T lymphocytes. Based on expression data measured by RT-qPCR for these genes in RNA extracted from quarter milk samples, we were able to identify four different types of milk samples, each with specific properties. One cluster was characterized by increased expression of genes typifying neutrophils, a second one was identified by increased expression of genes typifying macrophages while the two others were distinguished based on the expression of genes associated with T lymphocytes. Clustering of samples based on gene expression was shown to be comparable to that obtained by flow cytometry analysis. Our results highlight the potential of profiling of milk samples based on gene expression for the analysis of the inflammatory status of udders.

pathology↗

bioRxiv2023

Neutrophil subsets play dual roles in tuberculosis by producing inflammasome dependent-IL-1β or suppressing T-cells via PD-L1

Neutrophils can be beneficial or deleterious during tuberculosis (TB). Based on the expression of MHC-II and programmed death ligand 1 (PD-L1), we distinguished two functionally and transcriptionally distinct neutrophil subsets in the lungs of mice infected with mycobacteria. Inflammatory [MHC-II-, PD-L1lo] neutrophils produced inflammasome-dependent IL-1{beta} in the lungs in response to virulent mycobacteria and "accelerated" deleterious inflammation, which was highly exacerbated in IFN-{gamma}R-/- mice. Regulatory [MHC-II+, PD-L1hi] neutrophils "brake" inflammation by suppressing T-cell proliferation and IFN-{gamma} production. Such beneficial regulation, which depends on PD-L1, is controlled by IFN-{gamma}R signaling in neutrophils. The hypervirulent HN878 strain from the Beijing genotype curbed PD-L1 expression by regulatory neutrophils, abolishing the braking function and driving deleterious hyper-inflammation in the lungs. These findings add a layer of complexity to the roles played by neutrophils in TB and may explain the reactivation of this disease observed in cancer patients treated with anti-PD-L1. One Sentence SummaryRegulatory and inflammatory neutrophil subsets play inverse roles in tuberculosis.

immunology↗

bioRxiv2021

LPS core type diversity in the Escherichia coli species and associations with phylogeny and virulence gene repertoire.

Escherichia coli is a very versatile species for which diversity has been explored from various perspectives highlighting, for example, phylogenetic groupings, pathovars as well as a wide range of O serotypes. The highly variable O-antigen, the most external part of the lipopolysaccharide component of the outer membrane of E. coli, is linked to the innermost lipid A through the core region of LPS of which 5 different structures, denominated K-12, R1, R2, R3 and R4, have been characterized so far. The aim of the present study was to analyze the prevalence of these LPS core types in the E. coli species and explore their distribution in the different E. coli phylogenetic groups and in relationship with the virulence gene repertoire. Results indicated an uneven distribution of core types between the different phylogroups, with phylogroup A strains being the most diverse in terms of LPS core types while phylogroups B1, D and E strains were dominated by the R3 type and phylogroups B2 and C strains being dominated by the R1 type. Strains carrying the LEE virulence operon were mostly of the R3 type whatever the phylogroup while, within phylogroup B2, strains carrying a K-12 core all belonged to the complex STc131, one of the major clone of extra-intestinal pathogenic E. coli (ExPEC) strains. The origin of this uneven distribution is discussed but remains to be explained, as well as the consequences of carrying a specific core type on the physiology of the bacteria. IMPACT STATEMENTThe diversity of the E. coli species in terms of type of infections is well known, and its surface O-antigen which shows some correspondence to pathogenicity. This study is the first one to report in detail the diversity and distribution of the LPS core types in the E. coli species using whole genome sequences. This distribution of the 5 know core types is analyzed in the different phylogroups along with their association with specific virulence gene repertoire. Results indicate a non-random distribution of LPS core types in the E. coli species and, most interestingly, preferential association of certain core types with either some phylogenetic clades or with particular virulence gene repertoires. This work is a first step towards the identification of the origin of this diversity as well as towards the exploration of the physiological properties associated with specific core types. DATA SUMMARYComplete list of strains with associated data is available in supplementary table S1.

microbiology↗