10 research outputs found

    Development of a human ex vivo melanoma model based on the implantation of tumor spheroids into skin explants

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    Le mĂ©lanome mĂ©tastatique est le cancer de la peau le plus agressif. Bien que son taux d’incidence soit infĂ©rieur Ă  1%, plus de 75% des dĂ©cĂšs associĂ©s Ă  un cancer de la peau lui sont attribuĂ©s. Au cours des derniĂšres annĂ©es, de nouvelles stratĂ©gies thĂ©rapeutiques ont permis d’amĂ©liorer la survie des patients. Cependant, des mĂ©canismes de rĂ©sistance Ă  ces traitements se dĂ©veloppent dans la majoritĂ© des cas, conduisant Ă  une phase de rechute, et une survie Ă  5 ans infĂ©rieure Ă  20%. Des modĂšles d’étude expĂ©rimentaux sont nĂ©cessaires afin de comprendre les mĂ©canismes impliquĂ©s dans l’apparition de ces rĂ©sistances et dĂ©velopper de nouvelles stratĂ©gies thĂ©rapeutiques. DiffĂ©rents modĂšles in vitro sont actuellement utilisĂ©s pour le dĂ©veloppement de drogues anti-tumorales, tels que celui du sphĂ©roĂŻde. Bien qu’il permette de reproduire l’organisation tridimensionnelle d’une tumeur, l’absence de microenvironnement tumoral empĂȘche l’étude des interactions entre les cellules tumorales et celui-ci alors que ces facteurs jouent un rĂŽle primordial dans la croissance tumorale et le dĂ©veloppement de mĂ©tastases. Dans ce contexte, mes travaux ont portĂ© sur le dĂ©veloppement et la caractĂ©risation d’un modĂšle ex vivo de mĂ©lanome humain complet permettant l’étude de l’évolution d’une tumeur dans le tissu sain et l’évaluation de composĂ©s pharmacologiques. Les travaux rĂ©alisĂ©s ont tout d’abord conduit au dĂ©veloppement d’un modĂšle de cancer cutanĂ© basĂ© sur la combinaison d’un modĂšle de sphĂ©roĂŻde de lignĂ©e cellulaire de mĂ©lanome humain et du modĂšle de peau humaine ex vivo NativeSkinÂź, dĂ©veloppĂ© par la sociĂ©tĂ© Genoskin. Une procĂ©dure a Ă©tĂ© dĂ©veloppĂ©e et validĂ©e pour permettre l’implantation reproductible d’un sphĂ©roĂŻde dans le derme des explants de peau. ParallĂšlement, j’ai dĂ©veloppĂ© une approche d’imagerie in situ par microscopie Ă  feuille de lumiĂšre aprĂšs transparisation des modĂšles. J’ai Ă©galement dĂ©veloppĂ© une stratĂ©gie d’analyse d’images permettant la caractĂ©risation quantitative de l'Ă©volution du sphĂ©roĂŻde implantĂ© en 3 dimensions et de suivre la dispersion des cellules du tumorales au sein de l’explant de peau. La caractĂ©risation histologique du modĂšle implantĂ© a rĂ©vĂ©lĂ© de façon trĂšs inattendue une perte progressive de l’intĂ©gritĂ© du sphĂ©roĂŻde aprĂšs implantation, associĂ©e Ă  une diminution rapide de la prolifĂ©ration des cellules le constituant et l’apoptose massive des cellules situĂ©es Ă  sa pĂ©riphĂ©rie. Ce phĂ©nomĂšne a Ă©tĂ© observĂ© de façon similaire lors de l’implantation de sphĂ©roĂŻdes produits Ă  partir de diffĂ©rents types cellulaires. Afin de comprendre ces rĂ©sultats, j’ai Ă©tudiĂ© l’implication potentielle de diffĂ©rents paramĂštres dans l’induction de la mortalitĂ© cellulaire observĂ©e tels que les conditions d’implantation, les facteurs synthĂ©tisĂ©s par le modĂšle et la contrainte mĂ©canique exercĂ©e par le derme. Les rĂ©sultats obtenus suggĂšrent que les facteurs sĂ©crĂ©tĂ©s par les modĂšles aprĂšs implantation du sphĂ©roĂŻde ont un effet antiprolifĂ©ratif sur les sphĂ©roĂŻdes de mĂ©lanome et qu’ils induisent la mortalitĂ© des cellules situĂ©es Ă  sa pĂ©riphĂ©rie. Par ailleurs, l’application d’une contrainte mĂ©canique extĂ©rieure sur les sphĂ©roĂŻdes de mĂ©lanome entraĂźne la perte de la cohĂ©sion de leur structure. Enfin, l’implantation de sphĂ©roĂŻdes dans le derme de biopsies de peau prĂ©alablement dessĂ©chĂ©es, induisant une perte de la viabilitĂ© cellulaire, a conduit Ă  des rĂ©sultats opposĂ©s Ă  ceux observĂ©s avec de la peau normale : la structure des sphĂ©roĂŻdes reste cohĂ©sive et la prolifĂ©ration des cellules est maintenue en pĂ©riphĂ©rie du sphĂ©roĂŻde sans qu’aucune apoptose massive ne soit observĂ©e. L'ensemble de ces travaux semble suggĂ©rer que la mortalitĂ© du sphĂ©roĂŻde pourrait ĂȘtre, en partie, la consĂ©quence d’une contrainte mĂ©canique exercĂ©e par la peau sur le sphĂ©roĂŻde et/ou de facteurs produits par la peau durant sa culture. Ces donnĂ©es ouvrent des perspectives intĂ©ressantes dans le domaine de l’ingĂ©nierie tissulaire pour l’évaluation pharmacologique de composĂ©s thĂ©rapeutiques.Malignant melanoma is the most aggressive form of skin cancer. Although it only occurs in less than 1%, it is responsible for more than 75% of skin cancer-related deaths. Furthermore, melanoma incidence has constantly increased during the last decades. New therapies such as targeted therapy and immunotherapy have emerged over the past years, significantly improving the overall survival rates of patients with advanced melanoma stages. However, resistance to those treatments develops in most cases, leading to relapse with a 5-years survival of those patients under 20%. Experimental models are needed in order to better understand the molecular events underlying these resistance mechanisms, and to develop new therapeutic strategies. MultiCellular Tumor spheroid is an increasingly recognized 3D in vitro model for pharmacological evaluation. Although this model accurately reproduces the 3D architecture, cell-cell interaction and cell heterogeneity found in microtumor in vivo, spheroids lack tumor-microenvironment interactions, which play a key role in tumor growth and metastasis development. In this context, the aim of my project was to develop and characterize a fully ex vivo human melanoma model for the study of tumor growth within the skin and the evaluation of antitumor drugs. Our approach relies on the combination of human melanoma cell lines grown in Multicellular Tumor Spheroids and the NativeSkinÂź model, an ex vivo human skin model produced by the biotechnology company Genoskin. Hence, I developed and validated a method to reproducibly implant one spheroid into the dermal compartment of skin explants cultured ex vivo. In parallel I have developed in situ imaging strategies based on light-sheet microscopy (SPIM, “Selective Plane Illumination Microscopy”) after optical clearing of the implanted skin biopsies. I also developed analytic methods to allow for the quantitative characterization of the spheroids evolution in 3 dimensions as well as tumor cells dispersal within the dermis of skin explants. Histological characterization of the implanted models over time revealed a progressive loss of the spheroids integrity after implantation associated with a rapid decrease in cell proliferation and massive apoptosis of the cells located in the peripheral layers. These results were shared by implanted spheroids made from different cell types. Further experiments were conducted in order to better understand these results and evaluate the impact of different parameters on the implanted microtumors viability such as the implantation procedure conditions, factors synthesized by the model after spheroid implantation and external mechanical stress. Results suggest that factors produced by the implanted models have an antiproliferative effect on melanoma spheroids and induce mortality in the peripheral layers of the spheroids. Moreover, results show that mechanical stress applied on melanoma spheroids induces loss of their cohesion. Finally, implantation of spheroids within the dermis of previously dessicated biopsies for 7 days, causing loss of skin cells viability, led to opposite results than in normal skin: spheroids maintain both a cohesive structure and proliferation in the peripheral cells without any massive apoptosis. Overall, this work led to the validation of a methodology to reproducibly implant spheroids into an ex vivo skin explant and the setup of an optical clearing technique necessary for in situ imaging of the implanted spheroid. Histological characterization unexpectedly revealed spheroids cells death following their implantation. Results suggest that this mortality could be partly related to mechanical stress exerted on the spheroids by the skin and/or by factors produced by the skin during culture. These data open new perspectives in the research field of tissue engineering for antitumoral pharmacology

    DĂ©veloppement d’un modĂšle humain de mĂ©lanome ex vivo basĂ© sur l’implantation de sphĂ©roĂŻdes dans des explants de peau

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    Malignant melanoma is the most aggressive form of skin cancer. Although it only occurs in less than 1%, it is responsible for more than 75% of skin cancer-related deaths. Furthermore, melanoma incidence has constantly increased during the last decades. New therapies such as targeted therapy and immunotherapy have emerged over the past years, significantly improving the overall survival rates of patients with advanced melanoma stages. However, resistance to those treatments develops in most cases, leading to relapse with a 5-years survival of those patients under 20%. Experimental models are needed in order to better understand the molecular events underlying these resistance mechanisms, and to develop new therapeutic strategies. MultiCellular Tumor spheroid is an increasingly recognized 3D in vitro model for pharmacological evaluation. Although this model accurately reproduces the 3D architecture, cell-cell interaction and cell heterogeneity found in microtumor in vivo, spheroids lack tumor-microenvironment interactions, which play a key role in tumor growth and metastasis development. In this context, the aim of my project was to develop and characterize a fully ex vivo human melanoma model for the study of tumor growth within the skin and the evaluation of antitumor drugs. Our approach relies on the combination of human melanoma cell lines grown in Multicellular Tumor Spheroids and the NativeSkinÂź model, an ex vivo human skin model produced by the biotechnology company Genoskin. Hence, I developed and validated a method to reproducibly implant one spheroid into the dermal compartment of skin explants cultured ex vivo. In parallel I have developed in situ imaging strategies based on light-sheet microscopy (SPIM, “Selective Plane Illumination Microscopy”) after optical clearing of the implanted skin biopsies. I also developed analytic methods to allow for the quantitative characterization of the spheroids evolution in 3 dimensions as well as tumor cells dispersal within the dermis of skin explants. Histological characterization of the implanted models over time revealed a progressive loss of the spheroids integrity after implantation associated with a rapid decrease in cell proliferation and massive apoptosis of the cells located in the peripheral layers. These results were shared by implanted spheroids made from different cell types. Further experiments were conducted in order to better understand these results and evaluate the impact of different parameters on the implanted microtumors viability such as the implantation procedure conditions, factors synthesized by the model after spheroid implantation and external mechanical stress. Results suggest that factors produced by the implanted models have an antiproliferative effect on melanoma spheroids and induce mortality in the peripheral layers of the spheroids. Moreover, results show that mechanical stress applied on melanoma spheroids induces loss of their cohesion. Finally, implantation of spheroids within the dermis of previously dessicated biopsies for 7 days, causing loss of skin cells viability, led to opposite results than in normal skin: spheroids maintain both a cohesive structure and proliferation in the peripheral cells without any massive apoptosis. Overall, this work led to the validation of a methodology to reproducibly implant spheroids into an ex vivo skin explant and the setup of an optical clearing technique necessary for in situ imaging of the implanted spheroid. Histological characterization unexpectedly revealed spheroids cells death following their implantation. Results suggest that this mortality could be partly related to mechanical stress exerted on the spheroids by the skin and/or by factors produced by the skin during culture. These data open new perspectives in the research field of tissue engineering for antitumoral pharmacology.Le mĂ©lanome mĂ©tastatique est le cancer de la peau le plus agressif. Bien que son taux d’incidence soit infĂ©rieur Ă  1%, plus de 75% des dĂ©cĂšs associĂ©s Ă  un cancer de la peau lui sont attribuĂ©s. Au cours des derniĂšres annĂ©es, de nouvelles stratĂ©gies thĂ©rapeutiques ont permis d’amĂ©liorer la survie des patients. Cependant, des mĂ©canismes de rĂ©sistance Ă  ces traitements se dĂ©veloppent dans la majoritĂ© des cas, conduisant Ă  une phase de rechute, et une survie Ă  5 ans infĂ©rieure Ă  20%. Des modĂšles d’étude expĂ©rimentaux sont nĂ©cessaires afin de comprendre les mĂ©canismes impliquĂ©s dans l’apparition de ces rĂ©sistances et dĂ©velopper de nouvelles stratĂ©gies thĂ©rapeutiques. DiffĂ©rents modĂšles in vitro sont actuellement utilisĂ©s pour le dĂ©veloppement de drogues anti-tumorales, tels que celui du sphĂ©roĂŻde. Bien qu’il permette de reproduire l’organisation tridimensionnelle d’une tumeur, l’absence de microenvironnement tumoral empĂȘche l’étude des interactions entre les cellules tumorales et celui-ci alors que ces facteurs jouent un rĂŽle primordial dans la croissance tumorale et le dĂ©veloppement de mĂ©tastases. Dans ce contexte, mes travaux ont portĂ© sur le dĂ©veloppement et la caractĂ©risation d’un modĂšle ex vivo de mĂ©lanome humain complet permettant l’étude de l’évolution d’une tumeur dans le tissu sain et l’évaluation de composĂ©s pharmacologiques. Les travaux rĂ©alisĂ©s ont tout d’abord conduit au dĂ©veloppement d’un modĂšle de cancer cutanĂ© basĂ© sur la combinaison d’un modĂšle de sphĂ©roĂŻde de lignĂ©e cellulaire de mĂ©lanome humain et du modĂšle de peau humaine ex vivo NativeSkinÂź, dĂ©veloppĂ© par la sociĂ©tĂ© Genoskin. Une procĂ©dure a Ă©tĂ© dĂ©veloppĂ©e et validĂ©e pour permettre l’implantation reproductible d’un sphĂ©roĂŻde dans le derme des explants de peau. ParallĂšlement, j’ai dĂ©veloppĂ© une approche d’imagerie in situ par microscopie Ă  feuille de lumiĂšre aprĂšs transparisation des modĂšles. J’ai Ă©galement dĂ©veloppĂ© une stratĂ©gie d’analyse d’images permettant la caractĂ©risation quantitative de l'Ă©volution du sphĂ©roĂŻde implantĂ© en 3 dimensions et de suivre la dispersion des cellules du tumorales au sein de l’explant de peau. La caractĂ©risation histologique du modĂšle implantĂ© a rĂ©vĂ©lĂ© de façon trĂšs inattendue une perte progressive de l’intĂ©gritĂ© du sphĂ©roĂŻde aprĂšs implantation, associĂ©e Ă  une diminution rapide de la prolifĂ©ration des cellules le constituant et l’apoptose massive des cellules situĂ©es Ă  sa pĂ©riphĂ©rie. Ce phĂ©nomĂšne a Ă©tĂ© observĂ© de façon similaire lors de l’implantation de sphĂ©roĂŻdes produits Ă  partir de diffĂ©rents types cellulaires. Afin de comprendre ces rĂ©sultats, j’ai Ă©tudiĂ© l’implication potentielle de diffĂ©rents paramĂštres dans l’induction de la mortalitĂ© cellulaire observĂ©e tels que les conditions d’implantation, les facteurs synthĂ©tisĂ©s par le modĂšle et la contrainte mĂ©canique exercĂ©e par le derme. Les rĂ©sultats obtenus suggĂšrent que les facteurs sĂ©crĂ©tĂ©s par les modĂšles aprĂšs implantation du sphĂ©roĂŻde ont un effet antiprolifĂ©ratif sur les sphĂ©roĂŻdes de mĂ©lanome et qu’ils induisent la mortalitĂ© des cellules situĂ©es Ă  sa pĂ©riphĂ©rie. Par ailleurs, l’application d’une contrainte mĂ©canique extĂ©rieure sur les sphĂ©roĂŻdes de mĂ©lanome entraĂźne la perte de la cohĂ©sion de leur structure. Enfin, l’implantation de sphĂ©roĂŻdes dans le derme de biopsies de peau prĂ©alablement dessĂ©chĂ©es, induisant une perte de la viabilitĂ© cellulaire, a conduit Ă  des rĂ©sultats opposĂ©s Ă  ceux observĂ©s avec de la peau normale : la structure des sphĂ©roĂŻdes reste cohĂ©sive et la prolifĂ©ration des cellules est maintenue en pĂ©riphĂ©rie du sphĂ©roĂŻde sans qu’aucune apoptose massive ne soit observĂ©e. L'ensemble de ces travaux semble suggĂ©rer que la mortalitĂ© du sphĂ©roĂŻde pourrait ĂȘtre, en partie, la consĂ©quence d’une contrainte mĂ©canique exercĂ©e par la peau sur le sphĂ©roĂŻde et/ou de facteurs produits par la peau durant sa culture. Ces donnĂ©es ouvrent des perspectives intĂ©ressantes dans le domaine de l’ingĂ©nierie tissulaire pour l’évaluation pharmacologique de composĂ©s thĂ©rapeutiques

    Discovery of Predictors of Mycoplasma hyopneumoniae Vaccine Response Efficiency in Pigs: 16S rRNA Gene Fecal Microbiota Analysis

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    International audienceThe gut microbiota comprises a large and diverse community of bacteria that play a significant role in swine health. Indeed, there is a tight association between the enteric immune system and the overall composition and richness of the microbiota, which is key in the induction, training and function of the host immunity, and may therefore, influence the immune response to vaccination. Using vaccination againstMycoplasma hyopneumoniae(M. hyo) as a model, we investigated the potential of early-life gut microbiota in predicting vaccine response and explored the post-vaccination dynamics of fecal microbiota at later time points. At 28 days of age (0 days post-vaccination; dpv), healthy piglets were vaccinated, and a booster vaccine was administered at 21 dpv. Blood samples were collected at 0, 21, 28, 35, and 118 dpv to measureM. hyo-specific IgG levels. Fecal samples for 16S rRNA gene amplicon sequencing were collected at 0, 21, 35, and 118 dpv. The results showed variability in antibody response among individual pigs, whilst pre-vaccination operational taxonomic units (OTUs) primarily belonging toPrevotella, [Prevotella],Anaerovibrio, andSutterellaappeared to best-predict vaccine response. Microbiota composition did not differ between the vaccinated and non-vaccinated pigs at post-vaccination time points, but the time effect was significant irrespective of the animals' vaccination status. Our study provides insight into the role of pre-vaccination gut microbiota composition in vaccine response and emphasizes the importance of studies on full metagenomes and microbial metabolites aimed at deciphering the role of specific bacteria and bacterial genes in the modulation of vaccine response

    Searching for links between gut microbiota collected before vaccination and variabilities of vaccine response in pigs

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    International audienceUnderstanding and predicting why some animals respond better to vaccination than others is a main concern to strengthen vaccination efficiency. Our aim was to study whether the gut microbiota before vaccination presents composition patterns associated with individual variabilities of vaccine responses in pigs. Ninety-eight Large White piglets were vaccinated against the influenza A virus (IAV) at weaning at 28 days of age (D28) with a booster three weeks later. Stools were collected before the vaccination at D28, and were further processed to perform 16SRNA gene sequencing (Illumina MiSeq) and assess microbial taxonomic composition. The piglets’ humoral response was evaluated by ELISA of seric IAV-specific IgGs and by hemagglutination inhibition assays (HAI) at D49, D56, D63, and D146 to identify extreme animals with either high or low responses to vaccination. Piglets with a richer microbiota had higher levels of HAI at D63 (p<0.05) and had a tendency towards more IAV-specific IgGs. Extreme high and low responders for IAV-specific IgGs at D63 had also a dissimilar microbiota (p<0.01) and displayed differentially abundant operational taxonomic units (OTUs); bacteria from the Paludibacteraceae family and Prevotella genera were more abundant in high responders, while bacteria from Helicobacter and Escherichia-Shigella genera were more abundant in low responders (FDR<0.05). Thus, our results show that the faecal microbiota before vaccination could be further investigated to identify biomarkers predictive of vaccine response levels and analyse the underlying biology

    Searching for links between gut microbiota collected before vaccination and variabilities of vaccine response in pigs

    No full text
    International audienceUnderstanding and predicting why some animals respond better to vaccination than others is a main concern to strengthen vaccination efficiency. Our aim was to study whether the gut microbiota before vaccination presents composition patterns associated with individual variabilities of vaccine responses in pigs. Ninety-eight Large White piglets were vaccinated against the influenza A virus (IAV) at weaning at 28 days of age (D28) with a booster three weeks later. Stools were collected before the vaccination at D28, and were further processed to perform 16SRNA gene sequencing (Illumina MiSeq) and assess microbial taxonomic composition. The piglets’ humoral response was evaluated by ELISA of seric IAV-specific IgGs and by hemagglutination inhibition assays (HAI) at D49, D56, D63, and D146 to identify extreme animals with either high or low responses to vaccination. Piglets with a richer microbiota had higher levels of HAI at D63 (p<0.05) and had a tendency towards more IAV-specific IgGs. Extreme high and low responders for IAV-specific IgGs at D63 had also a dissimilar microbiota (p<0.01) and displayed differentially abundant operational taxonomic units (OTUs); bacteria from the Paludibacteraceae family and Prevotella genera were more abundant in high responders, while bacteria from Helicobacter and Escherichia-Shigella genera were more abundant in low responders (FDR<0.05). Thus, our results show that the faecal microbiota before vaccination could be further investigated to identify biomarkers predictive of vaccine response levels and analyse the underlying biology

    Late weaning is associated with increased microbial diversity and Faecalibacterium prausnitzii abundance in the fecal microbiota of piglets

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    Background: In pig production systems, weaning is a crucial period characterized by nutritional, environmental, and social stresses. Piglets transition from a milk-based diet to a solid, more complex plant-based diet, and their gut physiology must adapt accordingly. It is well established that piglets weaned later display improved health, better wean-to-finish growth performance, and lower mortality rates. The aim of this study was to evaluate the impact of weaning age on fecal microbiota diversity and composition in piglets. Forty-eight Large White piglets were divided into 4 groups of 12 animals that were weaned at different ages: 14 days (early weaning), 21 days (a common weaning age in intensive pig farming), 28 days (idem), and 42 days (late weaning). Microbiota composition was assessed in each group by sequencing the 16S rRNA gene using fecal samples taken on the day of weaning, 7 days later, and at 60 days of age. Results: In each group, there were significant differences in fecal microbiota composition before and after weaning (p < 0.05), confirming that weaning can drastically change the gut microbiota. Microbiota diversity was positively correlated with weaning ag e: microbial alpha diversity and richness were higher in piglets weaned at 42 days of age both on the day of weaning and 7 days later. The abundance of Faecalibacterium prausnitzii operational taxonomic units (OTUs) was also higher in piglets weaned at 42 days of age. Conclusions: Overall, these results show that late weaning increased gut microbiota diversity and the abundance of F. prausnitzii, a microorganism with positive effects in humans. Piglets might thus derive a competitive advantage from later weaning because they have more time to accumulate a higher diversity of potentially beneficial microbes prior to the stressful and risky weaning period

    Driving gut microbiota enterotypes through host genetics

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    Abstract Background Population stratification based on interindividual variability in gut microbiota composition has revealed the existence of several ecotypes named enterotypes in humans and various animal species. Enterotypes are often associated with environmental factors including diet, but knowledge of the role of host genetics remains scarce. Moreover, enterotypes harbor functionalities likely associated with varying abilities and susceptibilities of their host. Previously, we showed that under controlled conditions, 60-day-old pig populations consistently split into two enterotypes with either Prevotella and Mitsuokella (PM enterotype) or Ruminococcus and Treponema (RT enterotype) as keystone taxa. Here, our aim was to rely on pig as a model to study the influence of host genetics to assemble enterotypes, and to provide clues on enterotype functional differences and their links with growth traits. Results We established two pig lines contrasted for abundances of the genera pairs specifying each enterotype at 60 days of age and assessed them for fecal microbiota composition and growth throughout three consecutive generations. Response to selection across three generations revealed, per line, an increase in the prevalence of the selected enterotype and in the average relative abundances of directly and indirectly selected bacterial genera. The PM enterotype was found less diverse than the RT enterotype but more efficient for piglet growth during the post-weaning period. Shotgun metagenomics revealed differentially abundant bacterial species between the two enterotypes. By using the KEGG Orthology database, we show that functions related to starch degradation and polysaccharide metabolism are enriched in the PM enterotype, whereas functions related to general nucleoside transport and peptide/nickel transport are enriched in the RT enterotype. Our results also suggest that the PM and RT enterotypes might differ in the metabolism of valine, leucin, and isoleucine, favoring their biosynthesis and degradation, respectively. Conclusion We experimentally demonstrated that enterotypes are functional ecosystems that can be selected as a whole by exerting pressure on the host genetics. We also highlight that holobionts should be considered as units of selection in breeding programs. These results pave the way for a holistic use of host genetics, microbiota diversity, and enterotype functionalities to understand holobiont shaping and adaptation. Video Abstrac
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