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Organ Transplant

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

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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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Immunization with lipopolysaccharide-deficient whole cells provides protective immunity in an experimental mouse model of Acinetobacter baumannii infection.

9. García-Quintanilla M., Pulido M.R., Pachón J. and McConnell, M.J.* Immunization with lipopolysaccharide-deficient whole cells provides protective immunity in an experimental mouse model of Acinetobacter baumannii infection. PLOS One. 2014 Dec 8;9(12).

PUBMED DOI

Varicella-zoster virus clades circulating in Spain over two decades.

I. González; A. Molina-Ortega; P. Pérez-Romero; J.E. Echevarría; L. He; D. Tarragó. Varicella-zoster virus clades circulating in Spain over two decades. Journal of Clinical Virology. 110, pp. 17- 21. 2019.

PUBMED DOI

Human herpesvirus 8-associated inflammatory cytokine syndrome.

M. Prieto-Barrios; R. Aragón-Miguel; D. Tarragó-Asensio; A. Lalueza; C. Zarco-Olivo. Human herpesvirus 8-associated inflammatory cytokine syndrome. JAMA Dermatology. 154 - 2, pp. 228 - 230. 2018.

PUBMED DOI

Encephalitis associated with human herpesvirus-7 infection in an immunocompetent adult.

M. Parra; A. Alcala; C. Amoros; A. Baeza; A. Galiana; D. Tarragó; M.Á. García-Quesada; V. Sánchez-Hellín. Encephalitis associated with human herpesvirus-7 infection in an immunocompetent adult. Virology Journal. 14 - 1, 2017.

PUBMED DOI

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Información adicional

La inducción de la tolerancia al aloinjerto sigue siendo una meta por alcanzar en el trasplante de órganos. La mayoría de las estrategias terapéuticas se centran en la inhibición del sistema inmunológico adaptativo, pero datos recientes demuestran que el reconocimiento alogénico de las células mieloides inicia el rechazo al trasplante. Terapias dirigidas hacia las células mieloides “in vivo” representan un objetivo potencial para inducir tolerancia inmunológica, pero permanece inexplorado clínicamente.Nuestro laboratorio utiliza una nanoinmunoterapia revolucionaria de nanopartículas de lipoproteínas de alta densidad (HDL) cargadas con rapamicina (mTORi-HDL) que previenen las modificaciones epigenéticas asociadas con la inmunidad entrenada, un estado funcional de los macrófagos recientemente descubierto. Usando un modelo experimental de trasplante en ratón, nuestros resultados demuestran que la administración de esta inmunoterapia con mTORi-HDL previene la respuesta inmunológica y promueve la tolerancia al órgano trasplantado.Nuestro laboratorio muestra un enfoque de investigación multidisciplinar articulado en tres objetivos diferentes para evaluar la relevancia clínica y los efectos terapéuticos de la inmunoterapia como preparación para un ensayo clínico en trasplante de órganos. Los objetivos generales estarán orientados a confirmar la identificación de la inmunidad entrenada como biomarcador y valor analítico para predecir el riesgo de rechazo en pacientes trasplantados bajo tres condiciones: periodos prolongadas de reperfusión isquémica (IRI) (objetivo 1), alosensibilización (objetivo 2) e infección (objetivo 3).

Induction of allograft tolerance remains a goal to be achieved in organ transplantation. Most therapeutic strategies focus on inhibition of the adaptive immune system, but recent data demonstrate that allogeneic recognition of myeloid cells initiates transplant rejection. Therapies targeting myeloid cells “in vivo” represent a potential target to induce immunological tolerance, but remain clinically unexplored. 

Our laboratory uses a revolutionary nanoimmunotherapy of high-density lipoprotein (HDL) nanoparticles loaded with rapamycin (mTORi-HDL) that prevents epigenetic modifications associated with trained immunity, a recently discovered functional state of macrophages. Using an experimental mouse transplant model, our results demonstrate that the administration of this immunotherapy with mTORi-HDL prevents the immune response and promotes tolerance to the transplanted organ. 

Our laboratory shows a multidisciplinary research approach articulated in three different objectives to evaluate the clinical relevance and therapeutic effects of immunotherapy in preparation for a clinical trial in organ transplantation. The general objectives will be aimed at confirming the identification of trained immunity as a biomarker and analytical value to predict the risk of rejection in transplant patients under three conditions: prolonged periods of ischemic reperfusion (IRI) (objective 1), allosensitization (objective 2) and infection (objective 3).

Induction of allograft tolerance remains a goal to be achieved in organ transplantation. Most therapeutic strategies focus on inhibition of the adaptive immune system, but recent data demonstrate that allogeneic recognition of myeloid cells initiates transplant rejection. Therapies targeting myeloid cells “in vivo” represent a potential target to induce immunological tolerance, but remain clinically unexplored. 

Our laboratory uses a revolutionary nanoimmunotherapy of high-density lipoprotein (HDL) nanoparticles loaded with rapamycin (mTORi-HDL) that prevents epigenetic modifications associated with trained immunity, a recently discovered functional state of macrophages. Using an experimental mouse transplant model, our results demonstrate that the administration of this immunotherapy with mTORi-HDL prevents the immune response and promotes tolerance to the transplanted organ. 

Our laboratory shows a multidisciplinary research approach articulated in three different objectives to evaluate the clinical relevance and therapeutic effects of immunotherapy in preparation for a clinical trial in organ transplantation. The general objectives will be aimed at confirming the identification of trained immunity as a biomarker and analytical value to predict the risk of rejection in transplant patients under three conditions: prolonged periods of ischemic reperfusion (IRI) (objective 1), allosensitization (objective 2) and infection (objective 3).

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