Characterization of Torque Teno Virus (TTV) Genotypes and miRNA-TTV Shedding Dynamics in Saliva of COVID-19 Inpatients

• Grant number: 25/14844-3
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: January 15, 2026
• End date: January 14, 2027
• Field of knowledge: Health Sciences - Dentistry - Dental Clinics
• Principal Investigator: Paulo Henrique Braz da Silva
• Grantee: Rafael Antônio Velôso Caixeta
• Supervisor: Simone Giannecchini
• Host Institution: Faculdade de Odontologia (FO). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Università degli Studi di Firenze, Italy
• Associated to the scholarship: 23/17536-2 - Oral Shedding of Torque Teno Virus (TTV) in COVID-19 patients - possible biomarker of severity, BP.DR

Abstract

Torque teno virus (TTV) is a non-pathogenic component of the human virome, notable for its remarkable genetic diversity, currently comprising at least 39 genotypes. Its replication is closely linked to the host's immune status, with higher viral loads correlating with greater immunosuppression. TTV can also encode microRNAs (miRNAs), a feature believed to support immune evasion and explain its widespread presence in human populations. In the context of COVID-19, a disease marked by immune dysregulation and elevated proinflammatory markers, recent evidence suggests that TTV replication may be affected, positioning it as a potential biomarker of disease severity. Considering the positive miRNA-TTV expressions occur independently of detectable TTV viral loads and alongside the potential for coinfection and the heterogeneous distribution of TTV genotypes, the aim of the study is identifying the predominant genotypes in saliva samples from patients hospitalized with moderate to severe COVID-19 complications, and to analyze the expression and dynamics of TTV-encoded miRNAs. Saliva samples were collected at multiple time points, from hospital admission to clinical outcome (discharge or death). Viral genotyping will be carried out using amplicon-based next-generation sequencing (Amplicon NGS), while the detection and quantification of TTV miRNAs will be performed through RT-qPCR. (AU)