Unlocking the complement-suppressing potential of factor H with a bacterial polypeptide

Lead Research Organisation: University of Edinburgh
Department Name: Sch of Chemistry

Abstract

A challenge in medicine is that contact between blood and manmade devices (such as intra-vascular stents used in cardiac surgery or dialysis equipment for kidney-failure patients) can trigger part of the human immune system called the complement cascade, with dire clinical consequences. We discovered that PspCN, a polypeptide of microbial origin, "turbocharges" a human protein (CFH) that inhibits the complement cascade. Guided by the results of a market assessment, we now propose to design, manufacture and test PspCN-decorated surface coatings for medical implants. We aim to demonstrate that the PspCN displayed on these potentially protective coatings will grab hold of CFH, which is abundant in blood, and induce the captured CFH to switch from a latent to an activated form. Thus, in an improvement on the efforts of competitors to utilize CFH in its latent form, our approach will afford coated surfaces that are protected from the complement cascade by the patient's own, activated, CFH.
 
Description Our goal was to explore the utility of a bacterial peptide as an anchor for the human suppressor of complement, factor H (FH), which is abundant in blood. We were hoping to emulate the bacterial complement-evasion strategy whereby FH is both irreversibly bound on the bacterial surface and held in a functionally enhanced form that ensures it acts as a potent blocker of C3b amplification and deposition. The ultimate aim was to attach the bacterial peptide onto the manmade surfaces lining medical devices as a means to protect them against damage from the two linked pathways of complement and clotting.

As planned we were able to immobilise the N-terminal domain of the D39 Streptococcus pneumoniae protein PspC (i.e. PspCN) to surfaces. We engineered N-terminal and C-terminal Cys (-SH) labelled versions and found the N-terminally labelled version performed better. We initially used maleimide-coated polystyrene multi-well plates to show that we could covalently attach SH-PspCN and use this to anchor factor H (detected by an anti-FH antibody). We were able to show convincing decreases in C3b deposition (monitored with an anti-C3b antibody) on the PspCN/FH-decorated surfaces compared to controls.

We were subsequently able to immobilise PspCN on a range of other materials including polymers developed (by Mark Bradley's laboratory) for stent coatings that favour re-endothelialilasion of stent-damaged arterial segments. We were also able to illustrate the potential utility of PspCN on bare-metal stents by coating metal strips with PspCN. In suppression of complement activation assays (C3-deposition, C5b-9 formation) the coated strips easily outperformed uncoated ones.

Also in line with our objectives we looked at PspCN from other strains of S. pneumoniae. We found that certain truncations of TigR4 PspCN has very similar functions to D39 PspCN (including the anchoring and activating of FH), despite having only low sequence similarity. Indeed _none_ of the residues of TigR4 that were critical to its complex with FH (according to a crystal structure of the complex) were conserved in D39 PspCN. This was consistent with out hypothesis that FH can oscillate between different conformations, one of which is readily stabilised by binding of a protein to its modules 8-10, with the actual details of the binding being of only secondary importance.

With potential therapeutic uses in mind, we also prepared PEGylated SH-PspCN, in line with our aims, and showed that it retained the biological properties of the non-PEGylated material. Our collaborators in the USA showed that our PEGylatd PspCN was less immunogenic than the nonPEGylatd version in mice.

Our results were used to obtain further funding from Scottish Enterprise for development of "H-guard", a PspCN-based coating for medical devices with novel anti-complement properties.
Exploitation Route Our attempts to spin-out a company making medical device coatings are well advanced and we have successfully obtained Phase II of Scottish Enterprise High-Growth Spinout funding.

The therapeutic use of PspC as an enhancer of Fh in age-related macular degeneration is an exciting possibility. We have a commercial partner who has funded PK studies in mice and NHPs (conducted by a CRO in the US).
Sectors Healthcare,Pharmaceuticals and Medical Biotechnology
 
Description Andrew Herbert who was a PDRA on the grant is the founder and CTO of Invizius, a spinout that launched January 2018. Invizius has now fully spun out from the University and is located in Glasgow BioCity with a team of six.
First Year Of Impact 2017
Sector Healthcare,Pharmaceuticals and Medical Biotechnology
Impact Types Economic
 
Description Industrial collaboration funding (one off)
Amount £150,000 (GBP)
Funding ID Fellowship Eliza Makou 
Organisation Gemini Therapeutics, Inc. 
Sector Private
Country United States
Start 02/2018 
End 02/2019
 
Description Medical Device Coatings (H-Guard) Phase 2
Amount £420,365 (GBP)
Funding ID PS7305CA45 
Organisation Scottish Enterprise 
Sector Public
Country United Kingdom
Start 09/2016 
End 04/2018
 
Description Research Project Grant
Amount £218,000 (GBP)
Funding ID RPG-2015-109 
Organisation The Leverhulme Trust 
Sector Charity/Non Profit
Country United Kingdom
Start 04/2015 
End 03/2017
 
Description Structural and functional studies of complement regulation
Amount £150,000 (GBP)
Organisation Gemini Therapeutics, Inc. 
Sector Private
Country United States
Start 01/2019 
End 01/2020
 
Description Ocular therapeutics 
Organisation Pathfinder Bio
Country United States 
Sector Private 
PI Contribution I will be a Scientific Founder of new ocular therapeutics company, Gemini Therapeutics. Focus is on complement and factor H. I have helped to raise seed funding from VCs. Our research team is contributing expertise in experimental design and data analysis and interpretation, preparation and testing of complement proteins for PK studies, advice and consultancies.
Collaborator Contribution James McLaughlin has led in company formation and raising seed funding.
Impact None yet - research activities commencing in March 2016
Start Year 2015
 
Description Partnership with Scottish Enterprise 
Organisation Scottish Enterprise
Country United Kingdom 
Sector Public 
PI Contribution Andrew Herbert in my research team is spinning out a company
Collaborator Contribution Exoertise, advice, the funding of salaries
Impact None yet
Start Year 2015
 
Title PROTEINS WITH DIAGNOSTIC AND THERAPEUTIC USES 
Description The present invention provides a recombinant protein capable of binding to complement factor H (CFH), and thereby inducing increased binding of C3d and C3b by bound CFH compared to unbound CFH. Methods and medical devices for using utilising the same are also described. 
IP Reference WO2015055991 
Protection Patent application published
Year Protection Granted 2015
Licensed Yes
Impact None
 
Company Name Gemini Therapeutics 
Description Gemini Therapeutics is a Boston-based precision medicine company focused on genetically-defined dry age-related macular degeneration (AMD) and associated rare genetic diseases. Gemini's therapeutic candidates are matched to molecular abnormalities found in patients with high clinical need and Gemini's broad multimodal pipeline includes monoclonal antibodies, recombinant proteins (including factor H) and gene therapies. Launched with funding from leading life science investors and powered by academic partnerships around the world, Gemini is developing a series of potentially first-in-class therapeutics. Paul Barlow (PI) and Andrew Herbert (PDRA on grant) are scientific co-founders of Gemini Therapeutics. 
Year Established 2017 
Impact Gemini raised > $43M in seed and Series-A funding from Atlas Ventures, Lightstone and Orbimed. Gemini have recently commenced enrolment in a Phase I study of intravitreal administration of FH to treat dry AMD.
Website https://www.geminitherapeutics.com
 
Company Name Invizius 
Description Invizius wants to improve outcomes for patients on dialysis, and other extra-corporeal treatments Extra-corporeal treatments like dialysis, and cardiopulmonary bypass, involve the circulation of the patient's blood supply through a machine. The patient's immune system treats the machine as a large, unwanted foreign body; the resulting inflammatory response contributes to a range of serious complications. Despite significant improvements in the quality and efficacy of hemodialysis therapy in recent years, cardiovascular disease (CVD) remains the leading cause of death for dialysis patients. Today, almost half of all dialysis patients die from cardiovascular complications, and life expectancy on dialysis is just one-third of normal. Cardiopulmonary bypass maintains blood circulation and oxygenation during open heart surgery, but drives up patients' risk of respiratory, hemotological and neurological complications. With its proprietary H-Guard™ biotechnology (based on our research into a bacterial peptide that modulates complement activation), Invizius is addressing the side effects of dialysis and other extra-corporeal treatments. 
Year Established 2018 
Impact Invizius has recently secured seed funding totalling nearly £3 from a consortium including Mercia Asset Management. Invizius, is now fully spun out and located in BioCity Glasgow with a team of 6. It is developing biocompatible medical devices such as dialysers coated with a functionally augmented form of FH (anchored by PspCN). It was named in 2018 as one of the 15 "Fierce Med Tech" companies, predicted to become one of the most important new companies in the industry.
Website https://www.invizius.com