Christiana A. Demetriou, Zuzanna Makowska, George M. Spyrou, Marta E. Alarcón-Riquelme, Orthodoxia Nicolaou, Maria Morell, Bernard Lauwerys, Andreas Hadjisavvas, Savvas Psarellis, Andreas Kousios, Kyriacos Kyriacou, Pauline Montigny, Aurélie De Groof, Kleitos Sokratous, Anastasis Oulas, Kyriaki Michailidou, UCL - SSS/IREC/MONT - Pôle Mont Godinne, UCL - SSS/IREC/FATH - Pôle de Pharmacologie et thérapeutique, UCL - (MGD) Service de rhumatologie, UCL - (SLuc) Service de rhumatologie, [Nicolaou,O, Sokratous,K, Hadjisavvas,A, Kyriacou,K] Department of Electron Microscopy/Molecular Pathology, The Cyprus Institute of Neurology and Genetics, Agios Dometios, Nicosia, Cyprus. [Nicolaou,O, Michailidou,K, Oulas,A, Spyrou,GM, Kyriacou,K] Cyprus School of Molecular Medicine, Agios Dometios, Nicosia, Cyprus. [Sokratous,K, Spyrou,GM] Bioinformatics Group, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus. [Sokratous,K] Present Address: OMass Therapeutics, The Schrödinger Building, Heatley Road, The Oxford Science Park, Oxford, UK. [Makowska,Z] Pharmaceuticals, Bayer AG, Berlin, Germany. [Morell,M, Alarcón-Riquelme,ME] Genomic Medicine Department, Centre for Genomics and Oncological Research (GENYO), Pfizer-University of Granada-Andalusian Regional Government, Granada, Spain. [De Groof,A, Montigny,P, Lauwerys,B] Institut de Recherche Expérimentale et Clinique, Université catholique de Louvain, Brussels, Belgium. [Montigny,P] CHU UCL Namur, Yvoir, Belgium. [Michailidou,K] Biostatistics Unit, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus. [Demetriou,D] Department of Primary Care and Population Health, University of Nicosia Medical School, Nicosia, Cyprus. [Alarcón-Riquelme,ME] Unit of Immunology and Chronic Disease, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden. [Psarellis,S] Department of Rheumatology, Nicosia General Hospital, Nicosia, Cyprus. [Kousios,A] Renal and Transplant Centre Hammersmith Hospital Imperial College Healthcare NHS Trust, London, UK. [Lauwerys,B] Department of Rheumatology, Cliniques Universitaires Saint-Luc, Brussels, Belgium., and The research leading to these results has received support from the Innovative Medicines Initiative Joint Undertaking under grant agreement no. 115565, resources of which are composed of financial contribution from the European Union’s Seventh Framework Programme (FP7/2007–2013) and EFPIA companies’ in kind contribution. Kleitos Sokratous, Anastasis Oulas and George M. Spyrou are funded by the European Commission Research Executive Agency Grant BIORISE (No. 669026), under the Spreading Excellence, Widening Participation, Science with and for Society Framework.
Background Approximately 50% of systemic lupus erythematosus (SLE) patients develop nephritis, which is among the most severe and frequent complications of the disease and a leading cause of morbidity and mortality. Despite intensive research, there are still no reliable lupus nephritis (LN) markers in clinical use that can assess renal damage and activity with a high sensitivity and specificity. To this end, the aim of this study was to identify new clinically relevant tissue-specific protein biomarkers and possible underlying molecular mechanisms associated with renal involvement in SLE, using mass spectrometry (MS)-based proteomics. Methods Kidneys were harvested from female triple congenic B6.NZMsle1/sle2/sle3 lupus mice model, and the respective sex- and age-matched C57BL/6 control mice at 12, 24 and 36 weeks of age, representing pre-symptomatic, established and end-stage LN, respectively. Proteins were extracted from kidneys, purified, reduced, alkylated and digested by trypsin. Purified peptides were separated by liquid chromatography and analysed by high-resolution MS. Data were processed by the Progenesis QIp software, and functional annotation analysis was performed using DAVID bioinformatics resources. Immunofluorescence and multiple reaction monitoring (MRM) MS methods were used to confirm prospective biomarkers in SLE mouse strains as well as human serum samples. Results Proteomic profiling of kidney tissues from SLE and control mice resulted in the identification of more than 3800 unique proteins. Pathway analysis revealed a number of dysregulated molecular pathways that may be mechanistically involved in renal pathology, including phagosome and proximal tubule bicarbonate reclamation pathways. Proteomic analysis supported by human transcriptomic data and pathway analysis revealed Coronin-1A, Ubiquitin-like protein ISG15, and Rho GDP-dissociation inhibitor 2, as potential LN biomarkers. These results were further validated in other SLE mouse strains using MRM-MS. Most importantly, experiments in humans showed that measurement of Coronin-1A in human sera using MRM-MS can segregate LN patients from SLE patients without nephritis with a high sensitivity (100%) and specificity (100%). Conclusions These preliminary findings suggest that serum Coronin-1A may serve as a promising non-invasive biomarker for LN and, upon validation in larger cohorts, may be employed in the future as a screening test for renal disease in SLE patients.