Can we use the modulation of those for development of new drugs against infectious and inflammatory diseases?

What is this research project about?

Reconstruction of the enzymatic cycle of human cGAS

What is this research project about?

The innate immune sensors activate interferon-driven antiviral responses upon recognition of pathogen-associated molecular patterns (PAMPs) and serve as a rheostat for the metabolic activity of the microbiota and its exposure to diet, xenobiotics, and infections. The ability to modulate innate immune sensors opens new ways to novel anti-viral and anti-inflammatory drugs, and therapies against cancer and many aging-associated metabolic, neoplastic, autoimmune or autoinflammatory disorders. The cGAS/OAS family of innate immune sensors is among the most promising targets for the development of new antimicrobial and immunomodulatory agents. cGAS/OAS share a highly conserved structure of the active sites with other nucleotide triphosphate transferases (NTPTs). Targeting active sites of cGAS/OAS may interfere with many important biological processes through unspecific inhibition (cross-reactivity). Allosteric regulation can solve the cross-reactivity problem and help develop specific activity modulators of the innate immune sensors.

What’s the current status?

Recently, we established the detailed mechanisms of nucleic acid-induced activation of OAS1 and cGAS, the individual roles of nucleic acids and substrates, the sources of 2’-specificity of product formation, and the basis of functional divergence between OAS1 and cGAS. We also developed a new method that allows the rational identification of allosteric sites for the specific regulation of enzymes with highly-conserved catalytic centers, and successfully demonstrated its applications. These data and methodology are currently being used to discover and test the potency of allosteric pathways as targets for modulating the activity of cGAS/OAS.

Crystals of cGAS

What are the project goals?

Our aims include (i) identification and validation of allosteric pathways that control enzymatic activity in human cGAS/OAS family; (ii) development of suitable chemical scaffolds for the generation of small-molecule activity modulators that target these pathways with high affinity and specificity; (iii) development of lead-compounds for the specific allosteric modulation of innate immune sensors, based on assays and test that are performed in vitro and in cellulo. The best candidates will be selected using animal model tests for further activity studies in clinical trials.

How do we get there?

To reveal communication pathways that connect the catalytic centers of innate immune sensors with suitably positioned allosteric pockets, we are dissecting the complete enzymatic cycles of cGAS and OAS1, using approaches that were successfully applied in our previous works on UDP-sugar pyrophosphorylases1,2 and myosin isoforms3,5. The available structural information will be further refined to obtain more detailed information about cGAS dynamics and allostery. Allosteric sites and communication pathways will be tested and validated by the generation of mutant constructs that bias the positioning of active structural elements in a well-defined manner. HPLC/MS-based assays have been established to measure the catalytic activity of wild-type and mutant constructs. Allosteric sites that pass the validation tests are used as targets for the development of small-molecule inhibitors or activators.

Crystals of OAS1


Project title: Towards Allosteric Modulation of cGAS/OAS family of innate immune sensors as a means to control infection and inflammation

Prof. Dr. Dietmar Manstein

Projekt: D4

CV & Contact

PD Dr. Roman Fedorov

Projekt: D4

CV & Contact

Project D4 Publications

Actin-tropomyosin distribution in non-muscle cells. Manstein DJ, Meiring JCM, Hardeman EC, Gunning PW. J Muscle Res Cell Motil. 2019 May 4. doi: 10.1007/s10974-019-09514-0.

Publikationen, die vor dem offiziellen Start von RESIST erschienen sind:

Identification of Leishmania major UDP-Sugar Pyrophosphorylase Inhibitors Using Biosensor-Based Small Molecule Fragment Library Screening. Prakash O, Führing J, Post J, Shepherd SM, Eadsforth TC, Gray D, Fedorov R and Routier FH.  2019, Molecules, 24(5): 996.

Decoding Allosteric Networks in Biocatalysts: Rational Approach to Therapies and Biotechnologies. Cramer JT, Führing JI, Baruch P, Brütting C, Knölker H-J, Gerardy-Schahn R, Fedorov R. 2018, ACS Catalysis. 8:2683-2692.

Mechanistic insights into the active site and allosteric communication pathways in human nonmuscle myosin-2C. Chinthalapudi K, Heissler SM, Preller M., Sellers JR, Manstein DJ. 2017, eLife 6:e32742

The activation mechanism of 2’-5’-oligoadenylate synthetase gives new insights into OAS/cGAS triggers of innate immunity. Lohöfener J, Steinke N, Kay-Fedorov P, Baruch P, Nikulin A, Tishchenko S, Manstein DJ, and Fedorov R.  2015, CELL Structure. 23(5):851-862.

Small molecule-mediated refolding and activation of myosin motor function. Radke, MB, Taft, MH, Stapel, B, Hilfiker-Kleiner, D, Preller, M, and Manstein, DJ. 2014, Elife 3: e01603

Project D4