A dynamic insight into the interaction of Chlamydia trachomatis with host cells

Lead Research Organisation: University of Cambridge
Department Name: Medicine

Abstract

Infection by the bacteria Chlamydia trachomatis, or chlamydia, imparts a large burden on society, particularly amongst young adults. It contributes significantly to the prevalence of sexually transmitted diseases and is a key cause of infertility and preventable blindness. Unlike many other types of bacteria, chlamydia cannot replicate outside of a cell. It is obligated to enter a cell in order to reproduce. As a result, it has evolved the ability to manipulate the environment of the host cell to keep the cell alive for the appropriate length of time; because if the host cell dies too quickly, the chlamydia will also die. In order to develop strategies to tackle this major public health problem, we will need to have a better understanding of what happens to the host cell and to the chlamydia during the infection process. Thus we will use a powerful new technique, which will allow us to accurately determine what happens to host cell and chlamydia proteins, as well as how they interact with each other, over the course of the infectious life cycle. In addition, we want to identify whether the chlamydia prevents the body's immune system or defence mechanisms working properly We think that the chlamydia may influence the types of proteins on the surface of the cell, and change the way the immune system cells react to an infection, so that the bacteria can persist. In order to study this, we will compare the proteins on the cell surface before and after infection. Both these approaches will help us better understand how chlamydia successfully enters cells, replicates and manipulates its environment. This knowledge is critical if we are to devise strategies to prevent humans succumbing to the infection and most importantly, the irreversible damage to the body that results in blindness and infertility.

Technical Summary

Chlamydia trachomatis (CT) infection imparts a large burden on the human population, particularly amongst young adults, contributing significantly to the prevalence of sexually transmitted diseases, infertility and preventable blindness. CT is an obligate intracellular bacterium that is exquisitely adapted to manipulate the environment of the host cell. In contrast to gene expression studies, there is no information on the global protein changes that occur during the infectious process. Thus, we will utilise a powerful multiplexed proteomic technique that allows the relative abundance of chlamydia and host proteins to be determined accurately over the course of the infectious life cycle in both human epithelial and dendritic cells. This approach will provide the first opportunity to interrogate the chlamydia and host protein responses in tandem and provide a dynamic insight into the chlamydia-host interaction. A quantitative proteomics approach provides the opportunity to interrogate the biology of CT which has not been readily amenable to genetic manipulation approaches.
CT infection is also characterised by silent infection and inappropriate or inadequate cellular immunity to prevent reinfection. The plasma membrane provides a critical nexus with immune system cells and we hypothesize that changes in host cell plasma membrane proteins induced by CT infection may be critical in the modulation of immune responses. To address this, we will compare proteomic changes in the surface exposed membrane of human epithelial and dendritic cells infected CT. Both these approaches will identify pathways in the host cell response that that may be critical for either CT replication, induction of inflammatory responses and deviation of immune system responses. Most importantly, this study will inform potential approaches to prevent successful Chlamydia infection and its inflammatory sequelae in humans.

Planned Impact

Who will benefit from this research and how?

The immediate academic beneficiaries from this research would be the chlamydia research community. We will be providing important datasets of both the chlamydial proteome from disease relevant chlamydia strains and in addition a careful description of the host cell proteome response to these pathogens. However, if these results improve our understanding of the mechanisms underlying Chlamydia pathogenesis, it is certainly not too far-fetched to imagine that, the human population could directly benefit from improved diagnostics and treatment options and preventative measures that may occur as a result of these findings. The identification of novel chlamydia molecules that modulate the host cells will progress our understanding of immune response pathways and eventually inform interventions to treat or prevent inflammation and scarring associated with infection, thus impacting on human health.

Societal impact
Chlamydia infection is currently a large burden to human health. It is the leading cause of preventable blindness and one of the major causes of infertility. Thus, any progress made within the context of this project, that improves therapeutic and preventative strategies for chlamydia infection and treatment, no matter how small, would have significant impact. Although a significant reduction in incidence of trachoma and sexually transmitted chlamydia infection could be achieved by improvement in living conditions and a change in sexual behaviour. This must be accompanied by research that increases the understanding of the underlying mechanisms of chlamydia infection and the pathogenic process to enable the development of complementary strategies to combat the disease.
 
Description Provision of CGD patients 
Organisation Royal Free London NHS Foundation Trust
Country United Kingdom 
Sector Charity/Non Profit 
PI Contribution Analysis of the differentiated monocytes obtained from CGD patients
Collaborator Contribution Provision of CGD patients
Impact Publication submitted to the microbes and infection.
Start Year 2012
 
Description Raphael Valdvia 
Organisation Duke University
Country United States 
Sector Academic/University 
PI Contribution Analysis of a Chlamydia mutant bacteria
Collaborator Contribution Provision of mutant Chlamydia strains
Impact We are in the process of preparing a publication
Start Year 2015
 
Description Role of STING in inflammasome activation 
Organisation Radboud University Nijmegen
Department Department of Molecular Biology
Country Netherlands 
Sector Academic/University 
PI Contribution The aim of this collaborationwas to determine the role of STING in the activation of the inflammasome.
Collaborator Contribution Provision of bine marrow tissue from Wildtype and STING KO mice
Impact Manuscript in preparation
Start Year 2015
 
Description Southampton University 
Organisation University of Southampton
Department Centre for Biological Sciences
Country United Kingdom 
Sector Academic/University 
PI Contribution Analysis of proteome of chlamydia species by proteomic approaches
Collaborator Contribution Provision of Chlamydia trachomatis species for proteomic analysis.
Impact The reagents provided by this collaborator are currently being utilised.
Start Year 2017
 
Description The role of c-gas in chlamydia infection 
Organisation University of Oxford
Department Weatherall Institute of Molecular Medicine (WIMM)
Country United Kingdom 
Sector Public 
PI Contribution The collaboration involves our use of tissue from c-Gas KO mice. We will utilise the tissue using in vitro experiments to investigate the mechanism of STING activation in chlamydia infected cells.
Collaborator Contribution Jan Rehwinkel will provide tissues from transgenic mice that lack c-GAS expression
Impact The research has been submitted to PLOS pathogens and is currently under its second review
Start Year 2016
 
Description Attendance at 7th Biennial Meeting of the Chlamydia Basic Research Society April 2015 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact I presented the work to leaders in the field of chlamydia immunology and I was given very useful feedback and have formed some very useful collaborations. I will also sharing my data with a number of investigators to increase the impact of my work. There was a lot of interest in the technique I was using and I was able to discuss this with participants during my poster session.
Collaborations formed with Raphael Valdivia at Duke university. North Carolina.
Year(s) Of Engagement Activity 2015
 
Description Big Biology Day Careers fair 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact Fun, engaging and informative hands-on biology activity in Hills Road Sixth Form College. School students and members of the public have the chance to meet scientists and discuss research on chlamydia.
Year(s) Of Engagement Activity 2017
URL http://www.hillsroad.ac.uk/college-life/events/2017/10/14/default-calendar/big-biology-day
 
Description British Society of Immunology Annual meeting 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Presentation of a talk on the role of ER stress and pathogen associated molecules that result in the induction of pro-inflammatory cytokines to the attendees of the shared annual meeting of British Society for Immunology and the Dutch Society for Immunology, This talk was attended by scientists with an interest in the role of cytokines and macrophages in inflammation.
Year(s) Of Engagement Activity 2016
 
Description ER stress, autophagy and inflammation conference in Bruge 2017. 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Attended a meeting on the role of ER stress in inflammation. This meeting was critical to allow the networking and dissemination of information
Year(s) Of Engagement Activity 2016
 
Description Famelab regional final 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact The Science Festival provides the public with opportunities to explore and discuss issues of scientific interest and concern and to raise aspirations by encouraging young people to consider a career in science, technology, engineering or mathematics. The purpose of the famelab talks are to give short , high impact talks about the research project in an engaging and interesting manner.The talks are also videoed and made available nationally and internationally on Utube.
Year(s) Of Engagement Activity 2018
 
Description International Congress on Rickettsia and other Intracellular Bacteria 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact This was an invited lecture to present to the ESCCAR congress. This congress encourages basic and applied research in the field of chlamydiology, rickettsiology and related diseases due to intracellular bacteria. ESCCAR has currently about 300 members (medical doctors, veterinarians, microbiologists, ....) from many different countries. Bacterial diseases studied include chlamydiosis, rickettsiosis, bartonellosis, ehrlichosis, and coxiellosis as well as emerging infectious diseases due to novel intracellular bacteria (i.e. Chlamydia-related bacteria.
Year(s) Of Engagement Activity 2017
 
Description Invited lecture 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Professional Practitioners
Results and Impact The lecture was to present data on the chlamydia work to Scientists at the University of Southampton. Dept of Microbiology and Virology. As a result of this meeting , we have obtained different strains of chlamydia for our research from Prof. Ian Clarke.
Year(s) Of Engagement Activity 2017
 
Description Invited speaker at Oxford Glycobiology Institute 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Professional Practitioners
Results and Impact Lecture of my research This has resulted in a collaboration with Prof Joanna Miller, Glycobiology unit, University of Oxford.
Year(s) Of Engagement Activity 2015
 
Description Poster presentation at Cambridge Immunology forum 2015 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Poster presentation:STING regulates non-canonical inflammasome activation in response to Chlamydia trachomatis infection.
We were able to show our data and discusss with other leaders in the field of infection and inflammation.
As a result of this meeting we collaborated with Prof Vishva Dixit at Genentech
Year(s) Of Engagement Activity 2015
 
Description Year 11 Introduction to Science and IT , UTC Cambridge 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact In order to prepare our year 11 students for the future, I took part in a career event in Science and IT career opportunities in scientific research at the UTC, Cambridge. I provided an interactive workshop on aspects of scientific research and gave the students an opportunity to ask questions about career choices, career pathways, working conditions, job roles and responsibilities.
Year(s) Of Engagement Activity 2016
 
Description lecture at CIML 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Lecture to CIML, Marseille research scientists. As a result of this activity i have submitted a research grant application and formed a collbaoration.
Year(s) Of Engagement Activity 2018