Oral Lachnospiraceae plays a protective role in the host defense against respiratory herpesvirus infection and herpesvirus stimulated Pasteurella multocida infection

Description

The gut microbiota has been identified as pivotal for respiratory health, yet there remains limited understanding of its influence on respiratory coinfection. This study aimed to explore the impact of the gut microbiota on respiratory coinfection involving the zoonotic pathogens Suid herpesvirus 1 (SHV-1) and Pasteurella multocida (PM) using mouse models. Our findings revealed that SHV-1 infection disrupted the balance of the murine gut microbiota, exacerbating PM infection in mice, as demonstrated by 16S rRNA sequencing of murine fecal samples and fecal microbiota transplantation experiments. Analysis using LEfSe identified Lachnospiraceae as a significantly altered bacterial family between healthy mice and those infected with the pathogens. Subsequent mouse studies demonstrated that oral Lachnospiraceae effectively ameliorated PM infection triggered by SHV-1. Mechanistically, oral Lachnospiraceae restored the integrity of the respiratory barrier disrupted by SHV-1 infection. Furthermore, oral Lachnospiraceae restored several metabolites (such as disodium succinates, acetic acids, or butyric acids) that were altered by SHV-1 infection in the murine gut, as revealed by metabolomics sequencing. Treatment of mice with these metabolites alleviated symptoms and reduced mortality associated with the infection. These findings underscore the significant role of the “lung-gut axis” in respiratory infections.

Steps to reproduce

Solid samples The sample stored at -80 °C refrigerator was thawed on ice. A 400 μL solution (Methanol : Water = 7:3, V/V) containing internal standard was added into 20 mg sample, and vortexed for 3 min. The sample was sonicated in an ice bath for 10 min and vortexed for 1 min, and then placed in -20 °C for 30 min. The sample was then centrifuged at 12000 rpm for 10 min (4 °C). And the sediment was removed, then centrifuged the supernatant at 12000 rpm for 3 min (4 °C). A 200 μL aliquots of supernatant were transferred for LC-MS analysis HPLC Conditions All samples were for two LC/MS methods. One aliquot was analyzed using positive ion conditions and was eluted from T3 column (Waters ACQUITY Premier HSS T3 Column 1.8 µm, 2.1 mm * 100 mm) using 0.1 % formic acid in water as solvent A and 0.1 % formic acid in acetonitrile as solvent B in the following gradient: 5 to 20 % in 2 min, increased to 60 % in the following 3 mins, increased to 99 % in 1 min and held for 1.5 min, then come back to 5 % mobile phase B witnin 0.1 min, held for 2.4 min. The analytical conditions were as follows, column temperature, 40 °C; flow rate, 0.4 mL/min; injection volume, 4 μL; Another aliquot was using negative ion conditions and was the same as the elution gradient of positive mode. MS Conditions (QE) All the methods alternated between full scan MS and data dependent MSn scans using dynamic exclusion. MS analyses were carried out using electrospray ionization in the positive ion mode and negative ion mode using full scan analysis over m/z 75-1000 at 35000 resolution. Additional MS settings are: ion spray voltage, 3.5 KV or 3.2 KV in positive or negative modes, respevtively; Sheath gas (Arb), 30; Aux gas, 5; Ion transfer tube temperature, 320 °C; Vaporizer temperature, 300 °C; Collision energy, 30,40,50 V; Signal Intensity Threshold, 1*e6 cps; Top N vs Top speed, 10; Exclusion duration, 3s.

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Funders

• National Key Research and Development Program of China

  Grant ID: 2022YFA1305600
• Hubei Provincial Natural Foundation of China

  Grant ID: 2023AFA094

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