Project description:Histone lysine lactylation (Klac) is a new posttranslational modification (PTM) that is installed by acetyltransferase to modulate specific immune responses1 and oncogenesis2,3. Akkermansia muciniphila (A. muciniphila) is a beneficial bacterium that blunts ulcerative colitis (UC) in a mouse model by secreting extracellular vesicles (SEVs)4. Although many histone sites are known to contain lysine lactylation, whether this modification is regulated to modulate specific biological functions by exogenous acetyltransferase or intestinal microbiota is not well understood. Here, we discovered that SEV from A. muciniphila, rather than A. muciniphila per se, has anti-Th17 (T helper 17) differentiation activity. We further screened the composition of SEV and found that Amuc_2172 is the key active component. As a GCN5-related acetyltransferase of A. muciniphila, Amuc_2172 is accessible to naïve T cells and functions as a lactylation transferase on Lys4 of histone H3. Accelerated histone H3 lactylation (H3Klac) on Lys4 competitively blocks trimethylation (H3Kme3) on Il17a loci in the process of Th17-cell differentiation. Additionally, intraperitoneal application of recombinant Amuc_2172 also inhibited Th17 and dextran sulfate sodium (DSS)-induced UC phenotypes in vivo; moreover, bioengineered Amuc_2172 showed improved colitis site delivery and higher Th17 inhibition potential compared to Amuc_2172 alone. Our study reveals not only a potential therapeutic strategy for treating colitis but also a model via which lysine lactylation is regulated by the intestinal microbiota, which may be broadly applicable to understand the crosstalk of bacteria and immunity.
Project description:Histone lysine lactylation (Klac) is a new posttranslational modification (PTM) that is installed by acetyltransferase to modulate specific immune responses1 and oncogenesis2,3. Akkermansia muciniphila (A. muciniphila) is a beneficial bacterium that blunts ulcerative colitis (UC) in a mouse model by secreting extracellular vesicles (SEVs)4. Although many histone sites are known to contain lysine lactylation, whether this modification is regulated to modulate specific biological functions by exogenous acetyltransferase or intestinal microbiota is not well understood. Here, we discovered that SEV from A. muciniphila, rather than A. muciniphila per se, has anti-Th17 (T helper 17) differentiation activity. We further screened the composition of SEV and found that Amuc_2172 is the key active component. As a GCN5-related acetyltransferase of A. muciniphila, Amuc_2172 is accessible to naïve T cells and functions as a lactylation transferase on Lys4 of histone H3. Accelerated histone H3 lactylation (H3Klac) on Lys4 competitively blocks trimethylation (H3Kme3) on Il17a loci in the process of Th17-cell differentiation. Additionally, intraperitoneal application of recombinant Amuc_2172 also inhibited Th17 and dextran sulfate sodium (DSS)-induced UC phenotypes in vivo; moreover, bioengineered Amuc_2172 showed improved colitis site delivery and higher Th17 inhibition potential compared to Amuc_2172 alone. Our study reveals not only a potential therapeutic strategy for treating colitis but also a model via which lysine lactylation is regulated by the intestinal microbiota, which may be broadly applicable to understand the crosstalk of bacteria and immunity.
Project description:Propionibacterium freudenreichii is used as a ripening culture in Swiss cheese manufacture. It produces flavor compounds over the whole ripening period. During cheese ripening, P. freudenreichii is exposed to a temperature downshift, especially when cheeses are transferred from warm temperature (about 24°C) to cold temperature (about 4°C). The aim of this study was to investigate the adaptation of P. freudenreichii at cold temperature by means of the first global gene expression profile for this species. The temporal transcriptomic response of P. freudenreichii was analyzed at five times of growth, during growth at 30°C then for 9 days at 4°C, in the constant presence of lactate as the main carbon source. P. freudenreichii response was also investigated by RT-qPCR for 30 genes, by proteomics and metabolomics (main metabolites quantified in culture supernatant). Microarray analysis revealed that 565 genes (25% of the protein-coding sequences of P. freudenreichii genome) were differentially expressed during transition from warm to cold temperature (P < 0.05 and |fold change| > 1). Most of the down-expressed genes were involved in cell machinery (cell division, protein turnover, translation, transcription and DNA replication). During incubation at cold temperature, P. freudenreichii accumulated carbon supplies by up-regulating genes involved in lactate, alanine and serine conversion to pyruvate, in gluconeogenesis and in glycogen synthesis. Interestingly, some genes involved in the formation of important flavor compounds of cheese, coding for an extracellular lipolytic esterases and enzymes of the pathways of formation of branched-chain compounds, were not significantly affected by cold. In conclusion, P. freudenreichii is metabolically active at cold temperature and induces pathways to maintain its long-term viability, which could explain its contribution to cheese ripening even at low temperature.
Project description:Propionibacterium freudenreichii is used as a ripening culture in Swiss cheese manufacture. It produces flavor compounds over the whole ripening period. During cheese ripening, P. freudenreichii is exposed to a temperature downshift, especially when cheeses are transferred from warm temperature (about 24°C) to cold temperature (about 4°C). The aim of this study was to investigate the adaptation of P. freudenreichii at cold temperature by means of the first global gene expression profile for this species. The temporal transcriptomic response of P. freudenreichii was analyzed at five times of growth, during growth at 30°C then for 9 days at 4°C, in the constant presence of lactate as the main carbon source. P. freudenreichii response was also investigated by RT-qPCR for 30 genes, by proteomics and metabolomics (main metabolites quantified in culture supernatant). Microarray analysis revealed that 565 genes (25% of the protein-coding sequences of P. freudenreichii genome) were differentially expressed during transition from warm to cold temperature (P < 0.05 and |fold change| > 1). Most of the down-expressed genes were involved in cell machinery (cell division, protein turnover, translation, transcription and DNA replication). During incubation at cold temperature, P. freudenreichii accumulated carbon supplies by up-regulating genes involved in lactate, alanine and serine conversion to pyruvate, in gluconeogenesis and in glycogen synthesis. Interestingly, some genes involved in the formation of important flavor compounds of cheese, coding for an extracellular lipolytic esterases and enzymes of the pathways of formation of branched-chain compounds, were not significantly affected by cold. In conclusion, P. freudenreichii is metabolically active at cold temperature and induces pathways to maintain its long-term viability, which could explain its contribution to cheese ripening even at low temperature. Gene expression was measured in the middle of exponential growth phase at 30°C (20 h, OD650 ≈ 0.5), at the end of exponential growth phase (40 h, OD650 ≈ 2), and after 3, 6 and 9 days of incubation at 4°C. Three independent biological experiments were performed at each time (20h, 40h, 3, 6 and 9 days) and labelled A, B, C. One technical repetition was performed using the RNA of the 20HA sample ; This technical repetition was labelled 20HAbis.