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Bacterial Genetics

Líneas de investigación

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Bacterial Genetics

Our group has been studying for more than 30 years the mechanisms of antibiotic resistance in Streptococcus pneumoniae (Spn). Our objectives are to understand the molecular basis of antimicrobial action, to search for new targets of action and new compounds. Seconeolitsine (SCN) is one of these new compounds targeting topoisomerase I (Topo I). As for the search for new targets, our research has focused in recent years on the factors that organize the topology of the chromosome, allowing optimal compaction (about 1000-fold) to harmonize its replication, chromosome segregation and gene expression. This compaction is mediated both by the level of DNA supercoiling (Sc) and by association with nucleoid-binding proteins (NAPs). The level of Sc depends mainly on the enzymatic activities of their DNA topoisomerases, reaching a homeostatic equilibrium by the opposite activities of the topoisomerases that relax DNA (Topo I and Topo IV), and of gyrase, which introduces negative Sc. Our group has characterized the three Spn topoisomerases and two NAPs: HU and SatR. In addition, the availability of antimicrobials that inhibit each of the Spn topoisomerases has allowed us to analyze their transcriptome under conditions of local or global change of the Sc level and to define gene domains of coordinated transcription and similar functions. Fluoroquinolones, which inhibit Topo IV and gyrase, produce local changes in Sc that induce alterations in 6% of the transcriptome, altering metabolic pathways that originate an increase in reactive oxygen species (ROS) that contribute to lethality, in accordance with the general mechanism of bactericidal antibiotics. On the other hand, the induction of global changes in Sc by novobiocin (NOV, gyrase inhibitor), or by SCN (Topo I inhibitor), has allowed us to define topological domains. Global changes in Sc include the regulation of topoisomerase genes: its decrease activates the transcription of gyrase genes (gyrA, gyrB) and inhibits those of Topo IV (parEC) and Topo I (topA); the increase in Sc regulates the expression of topA. Decreased Sc affects 37% of the genome, with >68% of genes clustered in 15 domains. Increased Sc affects 10% of the genome, with 25% of the genes clustered in 12 domains. The AT content in the genome correlates with the domains, being higher in UP domains than in DOWN domains. The genes in the different domains have common functional characteristics, indicating that they have been subjected to topological selective pressure to determine the location of genes involved in metabolism, virulence and competition. 

The current objectives of the group are:
1.    Identification of factors that stabilize chromosome topology: NAPs, ncRNAs, intra-chromosomal interactions.
2.    Regulation of transcription in response to topological stress: in vivo localization of DNA topoisomerases, RNA polymerase and NAPs.
3.    Topo I as a new antimicrobial target and action of SCN. 
4.    Design of antisense RNAs and use of the CRISPR system as new antibacterial agents.

Proyectos de investigación

Content with Investigacion Genética Bacteriana .

1) Project Title: Interaction Between DNA Supercoiling and Transcription in the Human Pathogen  Streptococcus pneumoniae

Principal Investigator:   Adela González de la Campa  
Funding Entity:   Ministry of Science and Innovation, State Research Agency (Call for "R&D&I Projects" 2020 – "Research Challenges" and "Knowledge Generation" Modalities).  
Reference:   PID2021-124738OB-100.  
Duration:   2022-2025.  
Funding Amount:   €108,900.
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2) Project Title:   Study of the Factors Organizing the Chromosome of  Streptococcus pneumoniae: New Antibiotic Targets and Resistance Mechanisms.

Principal Investigator:   Adela González de la Campa  
Funding Entity:   Ministry of Economy, Industry, and Competitiveness. State Research Agency.  
Reference:   BIO2017-82951-R.  
Duration:   2018-2020.  
Funding Amount:   €169,400.  

3) Project Title:   Role of DNA Topoisomerases and Nucleoid-Associated Proteins in the Chromosome Organization of  Streptococcus pneumoniae: Response to Antibiotics and Virulence.  

Principal Investigator:   Adela González de la Campa  
Funding Entity:   Ministry of Economy and Competitiveness. Secretariat of State for Research, Development, and Innovation.  
Reference:   BIO2014-55462.  
Duration:   2015-2017.  
Funding Amount:   €193,600.  

4) Project Title:   The Control of Supercoiling Level in  Streptococcus pneumoniae  as an Antimicrobial Target.  

Principal Investigator:   Adela González de la Campa  
Funding Entity:   Ministry of Economy and Competitiveness. Secretariat of State for Research, Development, and Innovation.  
Reference:   BIO2011-25343.  
Duration:   2012-2015.  
Funding Amount:   €209,000.  

5) Project Title:   Role of Small Non-Coding RNAs in the Pathogenicity of  Streptococcus pneumoniae.   

Principal Investigator:   Mónica Amblar Esteban  
Funding Entity:   Ministry of Economy and Competitiveness. Strategic Health Action (AES).  
Reference:   PI11/00656.  
Duration:   2012-2015.  
Funding Amount:   €198,714.
 

Publicaciones destacadas

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Plasma metabolomic fingerprint of advanced cirrhosis stages among HIV/HCV-coinfected and HCV-monoinfected patients

Salguero, Sergio; Rojo, David; Berenguer, Juan; et al; Jimenez-Sousa, Maria A. (AC) (15/15). 2020. Plasma metabolomic fingerprint of advanced cirrhosis stages among HIV/HCV-coinfected and HCV-monoinfected patients LIVER INTERNATIONAL. 40-9, pp.2215-2227. ISSN 1478-3223. https://doi.org/10.1111/liv.14580 3

Telomere Length Increase in HIV/HCV-Coinfected Patients with Cirrhosis after HCV Eradication with Direct-Acting Antivirals JOURNAL OF CLINICAL MEDICINE.

Molina-Carrion, Silvia; Brochado-Kith, Oscar; Gonzalez-Garcia, Juan; et al; Jimenez-Sousa, Maria Angeles. (12/12). 2020. Telomere Length Increase in HIV/HCV-Coinfected Patients with Cirrhosis after HCV Eradication with Direct-Acting Antivirals JOURNAL OF CLINICAL MEDICINE. 9. ISSN 2077-0383. https://doi.org/10.3390/jcm9082407.

PBMCs gene expression signature of advanced cirrhosis with high risk for clinically significant portal hypertension in HIV/HCV coinfected patients

Salguero, Sergio; Brochado-Kith, Oscar; Verdices, Ana Virseda; et al; Jiménez-Sousa María A (‡, AC); Resino, Salvador (‡, AC). (12/12). 2023. PBMCs gene expression signature of advanced cirrhosis with high risk for clinically significant portal hypertension in HIV/HCV coinfected patients: A cross-control study. Biomedicine & pharmacotherapy. 159, pp.114220. ISSN 1950-6007.

Relative telomere length impact on mortality of COVID-19: Sex differences.Journal of medical virology.

Virseda-Berdices, Ana; Concostrina-Martinez, Leyre; Martinez-Gonzalez, Oscar; et al; Fernandez-Rodriguez, Amanda (‡), Jiménez-Sousa María A (‡). (14/14). 2023. Relative telomere length impact on mortality of COVID-19: Sex differences.Journal of medical virology. 95-1, pp.e28368. ISSN 1096-9071.

Plasma miRNA profile at COVID-19 onset predicts severity status and mortality.

Fernandez-Pato, Asier; Virseda-Berdices, Ana; Resino, Salvador; et al; Jiménez-Sousa María A (‡, AC); Fernandez-Rodriguez, Amanda (‡). (20/20). 2022. Plasma miRNA profile at COVID-19 onset predicts severity status and mortality. EMERGING MICROBES & INFECTIONS. 11(1):676-688. doi: 10.1080/22221751.2022.2038021.

Blood microbiome is associated with changes in portal hypertension after successful direct-acting antiviral therapy in patients with HCV-related cirrhosis.The Journal of antimicrobial chemotherapy.

Virseda-Berdices, Ana; Brochado-Kith, Oscar; Diez, Cristina; et al; Jimenez-Sousa, Maria Angeles. (16/16). 2021. Blood microbiome is associated with changes in portal hypertension after successful direct-acting antiviral therapy in patients with HCV-related cirrhosis.The Journal of antimicrobial chemotherapy. 77(3):719-726. doi: 10.1093/jac/dkab444. ISSN 1460-2091.

Chronic pulmonary aspergillosis update: A year in review. Med Mycol. 2019 Apr 1

Barac A, Kosmidis C, Alastruey-Izquierdo A, Salzer HJF; CPAnet. Chronic pulmonary aspergillosis update: A year in review. Med Mycol. 2019 Apr 1;57(Supplement_2):S104-S109. doi: 10.1093/mmy/myy070. PMID: 30816975.

PUBMED DOI

Laursen CB, Davidsen JR, Van Acker L, Salzer HJF, Seidel D, Cornely OA, Hoenigl M, Alastruey-Izquierdo A, Hennequin C, Godet C, Barac A, Flick H, Munteanu O, Van Braeckel E. CPAnet Registry-An International Chronic Pulmonary Aspergillosis Registry. J Fungi (Basel). 2020 Jun

Laursen CB, Davidsen JR, Van Acker L, Salzer HJF, Seidel D, Cornely OA, Hoenigl M, Alastruey-Izquierdo A, Hennequin C, Godet C, Barac A, Flick H, Munteanu O, Van Braeckel E. CPAnet Registry-An International Chronic Pulmonary Aspergillosis Registry. J Fungi (Basel). 2020 Jun 29;6(3):E96. doi: 10.3390/jof6030096. PMID: 32610566.

PUBMED DOI

Content with Investigacion Genética Bacteriana .

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Información adicional

Streptococcus pneumoniae is a human pathogen that, despite the development of vaccines, continues to be an important cause of mortality and morbidity. We investigate the mechanisms of antibiotic resistance in this bacterium. On the one hand by identifying new therapeutic targets and on the other hand by investigating the molecular basis of the action of antibiotics already used in clinical practice (the fluoroquinolones levofloxacin and moxifloxacin) or not yet used (seconeolitsine). For this purpose, we used a multidisciplinary analysis involving genomics, transcriptomics and proteomics to understand the organization of the S. pneumoniae chromosome and the identification of the factors that stabilize this organization, including ncRNAs. Changes in the level of global supercoiling, either by inhibition of gyrase (decrease) or by inhibition of topoisomerase I (increase) alter the transcriptome. The modulated genes are located in domains, whose genes show specific functional characteristics. The aim is to identify new factors essential for S. pneumoniae physiology and to characterize transcriptional regulation in response to topological stress. In addition, RNA interference technology and CRISPR systems will be used as novel antibacterials. These studies will establish the bases for translational research aimed at the development of new therapeutic targets for the treatment of pneumococcal diseases.

Streptococcus pneumoniae is a human pathogen that, despite the development of vaccines, continues to be an important cause of mortality and morbidity. We investigate the mechanisms of antibiotic resistance in this bacterium. On the one hand by identifying new therapeutic targets and on the other hand by investigating the molecular basis of the action of antibiotics already used in clinical practice (the fluoroquinolones levofloxacin and moxifloxacin) or not yet used (seconeolitsine). For this purpose, we used a multidisciplinary analysis involving genomics, transcriptomics and proteomics to understand the organization of the S. pneumoniae chromosome and the identification of the factors that stabilize this organization, including ncRNAs. Changes in the level of global supercoiling, either by inhibition of gyrase (decrease) or by inhibition of topoisomerase I (increase) alter the transcriptome. The modulated genes are located in domains, whose genes show specific functional characteristics. The aim is to identify new factors essential for S. pneumoniae physiology and to characterize transcriptional regulation in response to topological stress. In addition, RNA interference technology and CRISPR systems will be used as novel antibacterials. These studies will establish the bases for translational research aimed at the development of new therapeutic targets for the treatment of pneumococcal diseases.

Content with Investigacion Genética Bacteriana .

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