Dr Daniel Humphreys
UKRI Future Leaders Research Fellow
Room: C08 Florey building
My research focusses on the host cell biology underlying infectious diseases with the aim of discovering new ways to combat globally important bacterial pathogens. I am a UKRI Future Leaders Research Fellow studying DNA damage responses and senescence in typhoid fever and its transmission by chronic bacterial carriage. I obtained my PhD and gained postdoctoral training at the University of Cambridge before being appointed as a lecturer in 2016 at the Department of Biomedical Science, University of Sheffield, where I received an MRC New Investigator Research Grant. Before that I studied Microbiology at the University of Liverpool (BSc) and Biological Sciences at the University of Manchester (Masters).
Awards and funding
I am undergraduate module co-ordinator for Pathobiology BMS106/BMS109 in which I teach infection and immunity. I also lecture on the MSc for Molecular Medicine and the MSc for Antimicrobial Resistance.
Typhoid fever and its transmission by chronic bacterial carriage
Salmonella Typhi establishes infections through a wide repertoire of toxins and virulence effectors that mediate bacterial invasion of human cells, intracellular survival and immune evasion. A major focus of our laboratory is a key virulence determinant called the typhoid toxin that enters human cells where it causes breaks in our DNA, which activates a cellular alarm system known as the DNA damage response .
Our research also investigates how S.Typhi and its typhoid toxin cause chronic infections in humans - ‘chronic carriage’. Chronic carriers transmit the pathogen in the population and are difficult to control due to the lack of obvious clinical symptoms. The most infamous ‘chronic carrier’ was a household cook called Typhoid Mary who caused numerous outbreaks of typhoid between 1900 - 1906. This stealth strategy of S.Typhi continues today and helps S.Typhi perpetuate its infection cycle, which impedes global efforts to eradicate typhoid. By studying decisive disease mechanisms, our research contributes to global efforts combatting multidrug-resistant typhoid with the aim of improving the health and wealth of vulnerable communities in low- and middle-income countries.
Research projects on typhoid and chronic infection
Pathogenic bacteria manipulate the host DNA damage response (DDR) to execute virulence strategies and establish infections. This is exemplified by Salmonella Typhi that causes typhoid fever and fuels the infection cycle by chronic bacterial carriage. Upon infection, S.Typhi deploys the typhoid toxin, which is endocytosed by target host cells where the toxin activates the DDR. How the toxin hijacks the DDR and how this contributes to typhoid and chronic carriage is unclear. Understanding the toxin is especially important as related toxins are encoded by diverse bacterial pathogens that cause disease in humans and food-chain animals worldwide.
DNA damage responses underlying typhoid and chronic Salmonella carriage
Our laboratory is investigating the significance of DNA damage responses to infectious disease. We discovered a novel disease mechanism revealing that the typhoid toxin manipulates host cell machinery responsible for DNA replication and cell division. The typhoid toxin triggers accumulation of DNA repair protein γH2AX at the nuclear periphery - Response Induced by a bacterial Genotoxin (RING).
We found that the RING phenotype was caused by toxin subversion of replication protein A (RPA), which coats and protects single-strand DNA (ssDNA) at replication forks during DNA synthesis. By generating ssDNA breaks, toxin nuclease activity re-directs RPA from replication forks, which causes irreparable DNA damage (i.e. RING phenotype) resulting in DNA replication catastrophe and cellular senescence. Investigating this novel virulence mechanism is providing new information on disease while revealing potential therapeutic targets. Read the paper: http://rdcu.be/bQrD3
Investigating how pathogens accelerate the ageing of human host cells
Understanding how chronic infection develops, and identifying effective diagnostic, treatment and prevention strategies is vital to typhoid elimination efforts. We find that the typhoid toxin induces chronic DNA damage via the RING phenotype, which results in cellular senescence, a phenotype associated with ageing but whether pathogenic bacteria exploit senescence is unclear. Interestingly, protein secretions from intoxicated cells cause senescence in neighbouring cells but the identify of the secreted proteins and therefore the mechanism of this transmissible senescence is unresolved. Significantly, the senescent cells were rendered more susceptible to intracellular Salmonella infections.
Consequently, our findings support the view that pathogenic bacteria can speed up cellular ageing through a toxin and take advantage of this to establish infections. This makes sense as infections are often harder to combat and recover from as we age, which is partly due to senescence, but the idea that bacterial pathogens target this phenomenon could be important to infection and contribute to age-related pathologies such as cancer. We are investigating the significance of senescence in chronic infection and its diagnostic potential for typhoid and chronic carriage. Read more: http://rdcu.be/bQrD3
October 1, 2019
A big welcome to our new PhD student Salma Srour!
September 26, 2019
Daniel Humphreys awarded UKRI Future Leaders Fellowship
September 19, 2019
Typhoid Fever: an age-old problem
September 9, 2019
Thanks to Take on Typhoid for highlighting our research.
September 7, 2019
Typhoid toxin accelerates cell ageing to enhance killer infection, study reveals
September 6, 2019
Typhoid toxin exhausts the RPA response to DNA replication stress driving senescence and Salmonella infection
July 31, 2019
Daniel Humphreys and collaborators awarded HIC-Vac Research Grant
May 18, 2019
Dr. Angela Ibler - Congratulations on receiving your PhD at the University of Cambridge!
PhD Project Opportunity
Enquires for postdoc, fellowship and PhD positions are welcome.
We are advertising a post-doc position soon.
We advertise PhD opportunities (Funded or Self-Funded) on FindAPhD.com
For further information and details of other projects on offer, please see the department PhD Opportunities page:
- Ibler AEM, ElGhazaly M, Naylor KL, Bulgakova NA, El-Khamisy SF & Humphreys D (2019) Typhoid toxin exhausts the RPA response to DNA replication stress driving senescence and Salmonella infection. Nature Communications, 10(1), 4040.
- Brooks ABE, Humphreys D, Singh V, Davidson AC, Arden SD, Buss F & Koronakis V (2017) MYO6 is targeted by Salmonella virulence effectors to trigger PI3-kinase signaling and pathogen invasion into host cells. Proceedings of the National Academy of Sciences, 114(15), 3915-3920. View this article in WRRO
- Humphreys D, Singh V & Koronakis V (2016) Inhibition of WAVE Regulatory Complex Activation by a Bacterial Virulence Effector Counteracts Pathogen Phagocytosis. Cell Reports, 17(3), 697-707. View this article in WRRO
- Humphreys D, Davidson AC, Hume PJ, Makin LE & Koronakis V (2013) Arf6 coordinates actin assembly through the WAVE complex, a mechanism usurped by Salmonella to invade host cells. Proceedings of the National Academy of Sciences, 110(42), 16880-16885.
- Humphreys D, Davidson A, Hume PJ & Koronakis V (2012) Salmonella Virulence Effector SopE and Host GEF ARNO Cooperate to Recruit and Activate WAVE to Trigger Bacterial Invasion. Cell Host & Microbe, 11(2), 129-139.
- Humphreys D, Liu T, Davidson AC, Hume PJ & Koronakis V (2012) The Drosophila Arf1 homologue Arf79F is essential for lamellipodium formation. Journal of Cell Science, 125(23), 5630-5635.
- Humphreys D, Hume PJ & Koronakis V (2009) The Salmonella Effector SptP Dephosphorylates Host AAA+ ATPase VCP to Promote Development of its Intracellular Replicative Niche. Cell Host & Microbe, 5(3), 225-233.