Dr Daniel Humphreys

Dan Humphreys

Lecturer
Department of Biomedical Science
University of Sheffield
Western Bank
Sheffield S10 2TN
United Kingdom

Room: C 08 Florey building
Telephone: +44(0) 114 222 4632
Email: d.humphreys@sheffield.ac.uk

CMIAD


Cell Biology and Cancer

Overview

Brief career History

  • 2016: Lecturer, Department of Biomedical Science, The University of Sheffield
  • 2014 - 2016: Research Fellow and Principal Investigator, University of Cambridge
  • 2008 - 2013: Postdoctoral Research Associate, University of Cambridge
  • 2003 - 2007: PhD, University of Cambridge
  • 2002 - 2003: Masters of Biological Research, University of Manchester
  • 1999 - 2002: Bachelors of Science, University of Liverpool

Research interests

Manipulation of mammalian host cell biology by bacterial toxins and virulence effectors.

Full publications

Research

Manipulation of mammalian host cell biology by bacterial toxins and virulence effectors

To establish infections within mammalian hosts, bacterial pathogens have evolved sophisticated strategies to exploit host cell biology. They deploy toxins and virulence effector proteins into our cells that hijack cellular processes to promote pathogen survival, replication and dissemination, and interfere with the host immune response.

We are interested in the cell biology subverted by bacterial pathogens and how this ultimately contributes to diseases that can have devastating consequences to the health of humans and animals. Understanding host-pathogen interactions is especially important when considering the human health threat posed by many bacterial pathogens that continue to develop multidrug resistance.

Bacterial manipulation of host cell biology

Bacterial pathogens are known to inject virulence effectors that hijack the actin cytoskeleton. For example, enteropathogenic and enterohaemorrhagic Escherichia coli generate ‘actin pedestals’ to colonise the host cell surface whilst Salmonella and Shigella invade cells by generating ‘membrane ruffles’.

Once inside cells, Salmonella survives within a vacuole and ‘evades destruction within lysosomes’. Shigella on the other hand uses ‘actin-based propulsion to ‘’rocket’ through the cell and even propel itself into uninfected neighbouring cells for dissemination. Salmonella, E.coli and Shigella also secrete cytolethal distending toxins that cause DNA damage to induce ‘cell cycle arrest’ and interfere with immune cell signalling.

Opportunities

PhD Project Opportunity

1. Bacterial-associated oncogenesis: How does the typhoid toxin of Salmonella Typhi manipulate the host DNA damage response?

Closing date: Monday, January 22, 2018

Project Description

BACKGROUND

The intracellular bacterial pathogen Salmonella Typhi causes systemic typhoid fever in humans resulting in 27 million cases of disease and 200,000 deaths each year. The Typhi problem is exacerbated by the rise of antibiotic strains that are spreading across the globe. We need to understand the host-pathogen interaction to combat this disease with novel therapeutics.

Human cell function depends on our DNA integrity and S.Typhi targets the DNA damage response to establish human infections by releasing a unique virulence protein called the typhoid toxin. The toxin enters human cells where it employs nuclease activity to create DNA double strand breaks and manipulate our DNA damage response (DDR). In healthy cells, aberrant DNA structures are targeted for repair by the DNA damage response (DDR), but malfunction underlies many diseases including cancer. This is important as the typhoid toxin plays a dual role in the disease by causing acute typhoid fever symptoms whilst also facilitating persistent infections, which is associated with cancer in chronically infected individuals. How the toxin interacts with the DDR to cause disease is not understood, and its significance to bacterial-associated oncogenesis is unknown.

PROJECT

We have identified 47 putative host targets of the toxin implicated in the DDR. The PhD student will determine whether the target DDR genes are essential for the toxin to hijack the DDR and promote disease. Putative hits will be investigated using purified toxin derivatives and infection models in combination with host cells harbouring target DDR gene knockouts or targeted by libraries of small molecule inhibitors.

The student will use Salmonella infection models, intoxication and cell transformation assays to investigate the significance of the DDR genes on pathogen persistence and the generation of bacterial-associated oncogenic phenotypes in intoxicated host cells. The student will gain from a research team with expertise in the typhoid toxin, Salmonella infection and host cell biology governing DNA damage repair. This package will ensure the best biomedical PhD training in molecular cell biology, fluorescence imaging and infection techniques, and provide a springboard for addressing DNA damage response mechanisms and its role in a bacterial infection of major global importance.

References

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. *First authors

Humphreys D, Singh V & Koronakis V (2016) Inhibition of WAVE Regulatory Complex Activation by a Bacterial Virulence Effector Counteracts Pathogen Article Inhibition of WAVE Regulatory Complex Activation by a Bacterial Virulence Effector Counteracts Pathogen Phagocytosis. Cell Reports, 17, 697-707.

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 of the United States of America, 110, 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 and Microbe, 11, 129-139.

Keywords: Biochemistry, Cancer / Oncology, Cell Biology / Development, Immunology, Microbiology


2. Cellular mechanisms underlying human infection by the human bacterial pathogen enterohaemorrhagic Escherichia coli (EHEC) 0157

Funding status: Competition funded project European/UK students only

This project is eligible for a department scholarship. These scholarships are awarded on a competitive basis – find out more on our funding webpage.

Project Description

Understanding the molecular basis of host-pathogen interactions has never been more important given the health threat posed to humans and farmed food chain animals by bacterial pathogens that continue to develop multidrug resistance. Enterohaemorrhagic Escherichia coli (EHEC) 0157:H7 is an important enteric food-borne pathogen causing life-threatening haemorrhage colitis and haemolytic ureic syndrome in humans. Currently no treatment is available for EHEC infections. Advancing our knowledge of the EHEC virulence mechanisms has the potential to combat disease by speeding the development of anti-infectives and broadening the scope for therapeutic intervention.

To colonise the human intestine, EHEC attaches to the host cell surface and generates ‘actin pedestals’, cell projections upon which the pathogen adheres that destroy intestinal microvilli and cause gastroenteritis. The critical formation of these actin pedestals is dependent upon a cocktail of virulence effector proteins that are injected into the host cell by EHEC and hijack the cellular actin cytoskeleton.

To combat this disease we need to identify the host targets of the virulence effectors and block their action with novel drugs. We are looking for an enthusiastic PhD candidate to identify human targets regulating actin pedestal formation by performing a high-throughput infection screen on host cells treated with a library of small interfering RNAs at the Sheffield RNAi Screening Facility. Putative targets will be investigated and the action of virulence effectors examined using a combination of recombinant pathogens and engineered host cells. In parallel, drug libraries will be used to examine whether we can combat the novel host-pathogen interactions. The combinatorial approaches will be used as a springboard to elucidate novel disease mechanisms and ensure the best PhD training in molecular cell biology, fluorescence imaging and infection techniques, and address a bacterial disease of major biomedical significance. 

References

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. *First authors

Humphreys D, Singh V & Koronakis V (2016) Inhibition of WAVE Regulatory Complex Activation by a Bacterial Virulence Effector Counteracts Pathogen Article Inhibition of WAVE Regulatory Complex Activation by a Bacterial Virulence Effector Counteracts Pathogen Phagocytosis. Cell Reports, 17, 697-707.

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 of the United States of America, 110, 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 and Microbe, 11, 129-139.

Keywords: Biochemistry, Cell Biology / Development, Immunology, Microbiology, Molecular Biology, Pathology


Contact information

For informal enquiries about these projects or the application process, please feel free to contact me.

For further information about other projects within the department and how to apply, see our PhD Opportunities page:

PhD Opportunities

Selected publications

Journal articles