Functional genomics: reverse engineering using high-throughput methods for serological and salivary analysis in patients with Sjögrens syndrome

Author(s)

Giovanna Piacenza Florezi

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Odontologia (FO/SDO)
• Defense date: 2022-08-02

Examining board members

Silvia Vanessa Lourenço; Celso Augusto Lemos Júnior; José Maria Soares Júnior; Mônica Teresa Veneziano Labate

• Advisor: Silvia Vanessa Lourenço; Eduardo Moraes Rego Reis

Abstract

Primary Sjögrens syndrome (pSS) is a progressive inflammatory autoimmune disease that affects the exocrine salivary and lacrimal glands. The main clinical manifestation of the disease is the sicca syndrome, which is characterized by the decrease of salivary and lacrimal secretions, leading to dry eye and dry mouth sensation. Although the pathophysiology of the pSS is partially described, the mechanisms that initiate the disease remain unclear. The diagnosis of pSS is established by clinical, serological, and histological correlation. There are, however, no specific biomarkers with enough scientific relevance to aid the diagnosis and to establish a prognosis index for the disease. Thus, this study aimed to apply high-throughput methods, to stablish a metabolic and proteomic profile from 19 female SS patients, diagnosed according to the ACR-EULAR consensus criteria, compared to 20 healthy volunteers. Clinical and demographical data was summarized, and samples from whole unstimulated saliva and serum were collected from all participants. The samples were analyzed quantitatively with mass spectrometry associated to chromatography techniques using the chromatographic system nanoElute nanoflow online coupled to a hybrid trapped ion mobility spectrometry-quadrupole time-of-flight mass spectrometer - timsTOF-PRO (Bruker Daltonics), for proteomics and the gas chromatography time-of-flight mass spectrometer - GC-TOF/MS - Pegasus HT (LECO), for metabolomics. Uni- and multivariate statistical tests were Applied to determine the most relevant metabolites and proteins in the discrimination of the SS patients and healthy volunteers. The metabolomic analysis through GC-MS, revealed distinct profiles between the saliva and serum from SS patients and healthy volunteers, presenting compounds involved in the synthesis of amino acids, purines, lipid metabolism and multiple compounds derived from the expossome. The same pattern was observed in the salivary proteome quantitative profiling, unveiling proteins involved in differentiation, activation an expansion of innate and adaptive immune responses; also, proteins involved in in the lipid metabolism associated with inflammatory processes. Finally, the integration of the salivary proteome and metabolome confirmed the identification of genes such as GNAI2, B2MG, NGAL, SLUR2, HS90, SODC and A2GL, as potential markers in the development of the disease. (AU)

• FAPESP's process: 18/00419-5 - Functional genomics: reverse engineering using high-throughput methods for serological and salivary analysis in patients with Sjögren's syndrome
• Grantee: Giovanna Piacenza Florezi
• Support Opportunities: Scholarships in Brazil - Doctorate