Alive Pathogenic and Saprophytic Leptospires Enter and Exit Human and Mouse Macrophages With No Intracellular Replication
Leptospira interrogans are pathogenic bacteria responsible for leptospirosis, a zoonosis impacting 1 million people per year worldwide. Leptospires can infect all vertebrates, but not all hosts develop similar symptoms. Human and cattle may suffer from mild to acute illnesses and are therefore consi...
| Main Authors: | , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Frontiers Media S.A.
2022-07-01
|
| Series: | Frontiers in Cellular and Infection Microbiology |
| Subjects: | |
| Online Access: | https://www.frontiersin.org/articles/10.3389/fcimb.2022.936931/full |
| _version_ | 1811223901674405888 |
|---|---|
| author | Ignacio Santecchia Delphine Bonhomme Stylianos Papadopoulos Pedro Escoll Alexandre Giraud-Gatineau Maryse Moya-Nilges Frédérique Vernel-Pauillac Ivo Gomperts Boneca Catherine Werts |
| author_facet | Ignacio Santecchia Delphine Bonhomme Stylianos Papadopoulos Pedro Escoll Alexandre Giraud-Gatineau Maryse Moya-Nilges Frédérique Vernel-Pauillac Ivo Gomperts Boneca Catherine Werts |
| author_sort | Ignacio Santecchia |
| collection | DOAJ |
| description | Leptospira interrogans are pathogenic bacteria responsible for leptospirosis, a zoonosis impacting 1 million people per year worldwide. Leptospires can infect all vertebrates, but not all hosts develop similar symptoms. Human and cattle may suffer from mild to acute illnesses and are therefore considered as sensitive to leptospirosis. In contrast, mice and rats remain asymptomatic upon infection, although they get chronically colonized in their kidneys. Upon infection, leptospires are stealth pathogens that partially escape the recognition by the host innate immune system. Although leptospires are mainly extracellular bacteria, it was suggested that they could also replicate within macrophages. However, contradictory data in the current literature led us to reevaluate these findings. Using a gentamicin–protection assay coupled to high-content (HC) microscopy, we observed that leptospires were internalized in vivo upon peritoneal infection of C57BL/6J mice. Additionally, three different serotypes of pathogenic L. interrogans and the saprophytic L. biflexa actively infected both human (PMA differentiated) THP1 and mouse RAW264.7 macrophage cell lines. Next, we assessed the intracellular fate of leptospires using bioluminescent strains, and we observed a drastic reduction in the leptospiral intracellular load between 3 h and 6 h post-infection, suggesting that leptospires do not replicate within these cells. Surprisingly, the classical macrophage microbicidal mechanisms (phagocytosis, autophagy, TLR–mediated ROS, and RNS production) were not responsible for the observed decrease. Finally, we demonstrated that the reduction in the intracellular load was associated with an increase of the bacteria in the supernatant, suggesting that leptospires exit both human and murine macrophages. Overall, our study reevaluated the intracellular fate of leptospires and favors an active entrance followed by a rapid exit, suggesting that leptospires do not have an intracellular lifestyle in macrophages. |
| first_indexed | 2024-04-12T08:40:29Z |
| format | Article |
| id | doaj.art-33faeedf681644fc96a715f5af680349 |
| institution | Directory Open Access Journal |
| issn | 2235-2988 |
| language | English |
| last_indexed | 2024-04-12T08:40:29Z |
| publishDate | 2022-07-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Cellular and Infection Microbiology |
| spelling | doaj.art-33faeedf681644fc96a715f5af6803492022-12-22T03:39:54ZengFrontiers Media S.A.Frontiers in Cellular and Infection Microbiology2235-29882022-07-011210.3389/fcimb.2022.936931936931Alive Pathogenic and Saprophytic Leptospires Enter and Exit Human and Mouse Macrophages With No Intracellular ReplicationIgnacio Santecchia0Delphine Bonhomme1Stylianos Papadopoulos2Pedro Escoll3Alexandre Giraud-Gatineau4Maryse Moya-Nilges5Frédérique Vernel-Pauillac6Ivo Gomperts Boneca7Catherine Werts8Institut Pasteur, Université Cité Paris, CNRS UMR6047, INSERM U1306, Unité de Biologie et Génétique de la Paroi Bactérienne, Paris, FranceInstitut Pasteur, Université Cité Paris, CNRS UMR6047, INSERM U1306, Unité de Biologie et Génétique de la Paroi Bactérienne, Paris, FranceInstitut Pasteur, Université Cité Paris, CNRS UMR6047, INSERM U1306, Unité de Biologie et Génétique de la Paroi Bactérienne, Paris, FranceInstitut Pasteur, Université Cité Paris, CNRS UMR6047, Unité Biologie des Bactéries Intracellulaires, Paris, FranceInstitut Pasteur, Université Cité Paris, CNRS UMR6047, Unité de Biologie des Spirochètes, Paris, FranceInstitut Pasteur, Université Cité Paris, Plateforme de Bio-imagerie Ultrastructurale, Paris, FranceInstitut Pasteur, Université Cité Paris, CNRS UMR6047, INSERM U1306, Unité de Biologie et Génétique de la Paroi Bactérienne, Paris, FranceInstitut Pasteur, Université Cité Paris, CNRS UMR6047, INSERM U1306, Unité de Biologie et Génétique de la Paroi Bactérienne, Paris, FranceInstitut Pasteur, Université Cité Paris, CNRS UMR6047, INSERM U1306, Unité de Biologie et Génétique de la Paroi Bactérienne, Paris, FranceLeptospira interrogans are pathogenic bacteria responsible for leptospirosis, a zoonosis impacting 1 million people per year worldwide. Leptospires can infect all vertebrates, but not all hosts develop similar symptoms. Human and cattle may suffer from mild to acute illnesses and are therefore considered as sensitive to leptospirosis. In contrast, mice and rats remain asymptomatic upon infection, although they get chronically colonized in their kidneys. Upon infection, leptospires are stealth pathogens that partially escape the recognition by the host innate immune system. Although leptospires are mainly extracellular bacteria, it was suggested that they could also replicate within macrophages. However, contradictory data in the current literature led us to reevaluate these findings. Using a gentamicin–protection assay coupled to high-content (HC) microscopy, we observed that leptospires were internalized in vivo upon peritoneal infection of C57BL/6J mice. Additionally, three different serotypes of pathogenic L. interrogans and the saprophytic L. biflexa actively infected both human (PMA differentiated) THP1 and mouse RAW264.7 macrophage cell lines. Next, we assessed the intracellular fate of leptospires using bioluminescent strains, and we observed a drastic reduction in the leptospiral intracellular load between 3 h and 6 h post-infection, suggesting that leptospires do not replicate within these cells. Surprisingly, the classical macrophage microbicidal mechanisms (phagocytosis, autophagy, TLR–mediated ROS, and RNS production) were not responsible for the observed decrease. Finally, we demonstrated that the reduction in the intracellular load was associated with an increase of the bacteria in the supernatant, suggesting that leptospires exit both human and murine macrophages. Overall, our study reevaluated the intracellular fate of leptospires and favors an active entrance followed by a rapid exit, suggesting that leptospires do not have an intracellular lifestyle in macrophages.https://www.frontiersin.org/articles/10.3389/fcimb.2022.936931/fullLeptospira interrogansLeptospira biflexamacrophagesintracellularityTLRshigh content confocal microscopy |
| spellingShingle | Ignacio Santecchia Delphine Bonhomme Stylianos Papadopoulos Pedro Escoll Alexandre Giraud-Gatineau Maryse Moya-Nilges Frédérique Vernel-Pauillac Ivo Gomperts Boneca Catherine Werts Alive Pathogenic and Saprophytic Leptospires Enter and Exit Human and Mouse Macrophages With No Intracellular Replication Frontiers in Cellular and Infection Microbiology Leptospira interrogans Leptospira biflexa macrophages intracellularity TLRs high content confocal microscopy |
| title | Alive Pathogenic and Saprophytic Leptospires Enter and Exit Human and Mouse Macrophages With No Intracellular Replication |
| title_full | Alive Pathogenic and Saprophytic Leptospires Enter and Exit Human and Mouse Macrophages With No Intracellular Replication |
| title_fullStr | Alive Pathogenic and Saprophytic Leptospires Enter and Exit Human and Mouse Macrophages With No Intracellular Replication |
| title_full_unstemmed | Alive Pathogenic and Saprophytic Leptospires Enter and Exit Human and Mouse Macrophages With No Intracellular Replication |
| title_short | Alive Pathogenic and Saprophytic Leptospires Enter and Exit Human and Mouse Macrophages With No Intracellular Replication |
| title_sort | alive pathogenic and saprophytic leptospires enter and exit human and mouse macrophages with no intracellular replication |
| topic | Leptospira interrogans Leptospira biflexa macrophages intracellularity TLRs high content confocal microscopy |
| url | https://www.frontiersin.org/articles/10.3389/fcimb.2022.936931/full |
| work_keys_str_mv | AT ignaciosantecchia alivepathogenicandsaprophyticleptospiresenterandexithumanandmousemacrophageswithnointracellularreplication AT delphinebonhomme alivepathogenicandsaprophyticleptospiresenterandexithumanandmousemacrophageswithnointracellularreplication AT stylianospapadopoulos alivepathogenicandsaprophyticleptospiresenterandexithumanandmousemacrophageswithnointracellularreplication AT pedroescoll alivepathogenicandsaprophyticleptospiresenterandexithumanandmousemacrophageswithnointracellularreplication AT alexandregiraudgatineau alivepathogenicandsaprophyticleptospiresenterandexithumanandmousemacrophageswithnointracellularreplication AT marysemoyanilges alivepathogenicandsaprophyticleptospiresenterandexithumanandmousemacrophageswithnointracellularreplication AT frederiquevernelpauillac alivepathogenicandsaprophyticleptospiresenterandexithumanandmousemacrophageswithnointracellularreplication AT ivogompertsboneca alivepathogenicandsaprophyticleptospiresenterandexithumanandmousemacrophageswithnointracellularreplication AT catherinewerts alivepathogenicandsaprophyticleptospiresenterandexithumanandmousemacrophageswithnointracellularreplication |