Viral Metagenomics of Cutaneous Epithelia in health and psoriasis disease.

CERRI, AGUSTINA; BOLATTI, ELISA M.; BERTAINA, CAROLINA; ZOREC, TOMAZ M; CASAL, PABLO E; HOSNJAK, LEA; PICCIRILLI, GUSTAVO; MOLTENI, ANA; POLJAK, MARIO; GIRI, ADRIANA A

Giessen

Workshop; 2nd European Psychoneuroimmunology Network Autumn School: The Skin-Brain Axis and the Breaking of Barriers; 2023

European Psychoneuroimmunology Network

IntroductionThe skin microbiome plays a crucial role in maintaining skin integrity and functions as a critical external barrier. Different investigations have shown that dysbiosis of the skin microbiome could cause or exacerbate skin diseases, including psoriasis. Up to date, investigations have focused in bacterial and fungal communities present in health and disease however, the knowledge about skin virome in psoriasis is scarce. In the last decades Next Generation Sequencing (NGS) along with novel bioinformatics tools has revolutionized the virome studies, allowing to investigate the viral compositions of unexplored biological niches such as the human skin.MethodsIn order to establish an adequate methodology for the study of the skin virome, 3 protocols for the processing of skin samples were evaluated: A) total DNA purification; B) filtration + ultracentrifugation + DNA purification; and C) purification of viral particles. For this, a pool of skin swabs collected from 30 individuals without skin pathologies were prepared, splited and processed with protocols A, B or C. The extracted DNA in each case was subjected to NGS (Hiseq 2000, Illumina). Reads were subjected to quality filtering using Bbduk program (BBTools v38.42) and human reads were substracted by Bowtie2 (v.2.2.5) using the reference genome hg38. Finally, viral taxonomic classification was performed with Centrifuge (v.1.0.3) and the NCBI viral reference database.ResultsIn total, 1,376,217 reads (A: 540,546; B: 349,762; C: 485,909) with adequate quality parameters were obtained, of which 116,265 reads (A: 20,418; B: 95,621; C: 226) mapped to 36 different viral families (A: 28; B: 22; C: 10). The families Papillomaviridae, Genomoviridae, Poxviridae and Arteriviridae were the most frequently found among the families of viruses that infect vertebrates. Although method B was the most effective in obtaining the highest number of viral sequences, method A showed greater viral family abundance and was chosen for further analysis.DiscussionPsoriasis is a chronic, multifactorial inflammatory skin disease that affects approximately 3% of the world population. The factors underlying its etiology are multiple and diverse. In order to identify potential markers that could be useful for diagnostics, prevention and/or treatment of psoriasis, is important to evaluate the potential differences between the skin virome in psoriatic patients and healthy volunteers. Since sample preparation is a bottleneck in NGS, this work provides relevant information for the processing of skin samples in studies aimed at understanding the role of the virome in skin pathologies. Finally, the optimized protocol was applied in a case-control study from 25 psoriatic patients and 30 healthy volunteers and the NGS data obtained is under analysis. Funding: ANPCyT (PICT-2020-00571), ASaCTei (IO-00257-19).