Study of host-microbiome interaction in vitiligo patients

Purpose:
The purpose of this grant is to study host-microbiome interaction in vitiligo patients.

Abstract
The purpose of this grant is to study host-microbiome interaction in vitiligo patients wherein the main scientific question is to define whether microbiome alteration, aberrant host immunosurveillance, and previous viral infections play a significant role in contributing to
vitiligo pathogenesis.

Vitiligo is one of the most psychologically devastating autoimmune skin diseases linked to lower self-esteem, psychological stress, and social stigmatization. Vitiligo is characterized by depigmented white spots on the skin affecting 0.5–1% of the population worldwide. Vitiligo
causes depressive disorder in 57% of patients, social phobia in 68%, and suicidal thoughts in 28%, which implies a significant psychological burden on patients with vitiligo. Besides, currently available treatments are ineffective, and there is an urgent need for novel treatment
options for vitiligo. Recent studies have reported the impact of the microbiome to the pathogenesis of numerous autoimmune diseases. However, the role of the gut microbiome in the development of vitiligo remains elusive. Thus, the present study is aimed at studying the mechanisms of interaction between the host and the microbiota to develop effective treatment approaches.

To study host-microbiome interaction in patients with vitiligo, three main tasks are proposed: to study the microbial composition, function, metabolic network, and the genetic composition of the intestinal microbiome of patients with vitiligo, using the “shotgun” metagenomic sequencing technology; to study host-microbiome interaction to uncover the contribution of the microbiota
to the disease onset and its progression, using a new IgA-coated sequencing technology (IgA-Seq) to identify immune-targeted microorganisms and their putative metabolites in vitiligo patients; to study the repertoire of circulating antibodies against unique viral proteins, a wide
range of known viruses that previously infected vitiligo patients, using programmed immunoprecipitation and phage display sequencing (PhIP-Seq) technology.

This study will help to identify strains of viruses and their proteins, potentially capable of inducing the development of vitiligo. The results obtained will make it possible to deepen our knowledge about the mechanisms of pathogenesis of vitiligo, which, in turn, will contribute to
the creation of a scientific basis for the identification of biomarkers and the development of new approaches for vitiligo therapy.

Project objectives
1) To study the composition, function, and metabolic network of the intestinal microbiome in vitiligo patients.
Explanation: To date, no studies have been conducted for the function, genetic makeup, andbmetabolic network of the gut microbiome in vitiligo. To address this gap in knowledge, we plan to investigate gut microbial composition and function, metabolic network, and genetic makeup using shotgun metagenomic sequencing technology. This modern next-generation sequencing
(NGS) tool helps to sequence multiple prokaryotes and eukaryotes, including bacteria, fungi, viruses, and other types of microorganisms all in a single run. The obtained results will address this important gap in knowledge and map the functional part in gut dysbiosis in vitiligo and its
potential role in disease pathogenesis.
2) To study the interaction between the gut microbiome and the host immune response.
Explanation: Studying the impact of the intestinal microbiome on the host’s immune response in patients with vitiligo will provide insights into the mechanisms of the disease pathogenesis. To accomplish the given objective, we propose to identify Immunoglobulin A (IgA)-coated bacteria using antibodies against human IgA and subsequent sequencing of the genes of these bacteria
(IgA-SEQ). This technology combines flow cytometry sorting of IgA-bound bacteria and 16S rRNA sequencing. Further, we will also perform a phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt2) to predict the microbial metabolic potential of
gut bacteria using marker gene data (16S gene). This combined approach enables the identification of immune-targeted microorganisms and their predicted metabolites in vitiligo patients. The obtained results will help to identify microorganisms within the gut microflora that are potentially involved in vitiligo development.
3) To study serum antibody repertoires against unique viral proteins from a wide range of known viruses in vitiligo patients.
Explanation: We employ a programmable phage-display immunoprecipitation and sequencing (PhIP-Seq) technology to study antibody repertoires against unique viral proteins for a wide range of known viruses that previously had infected vitiligo patients. We will investigate the presence of specific antibodies produced against 9 449 unique proteins of 1358 known strains
and types of human viruses in vitiligo patients. The data obtained using PhiP-Seq will contribute to understanding the role of the interaction between host immunity and viruses in vitiligo pathogenesis. In addition, a previous history of viral infections among vitiligo patients will help
to identify potential viruses (and their unique proteins) that may be contributing to an aberrant immune response leading to vitiligo.