The gut microbiota composition is shaped by disease activity and individual treatment responses in patients with multiple sclerosis

Veronika Ticha¹Stepan Coufal²Zuzana Jiraskova Zakostelska^2*Tomas Thon²Radka Roubalova²Tomas Hrncir³Miloslav Kverka²Miluse Pavelcova¹Pavlina Kleinova¹Jana Lizrova Preiningerova¹Ivana Kovarova¹Jakub Kreisinger⁴Helena Tlaskalova-Hogenova²Eva Kubala Havrdova¹

• ¹Department of Neurology and Centre of Clinical Neuroscience, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czechia
• ²Laboratory of Cellular and Molecular Immunology, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czechia
• ³Laboratory of Gnotobiology, Institute of Microbiology of the Czech Academy of Sciences, Novy Hradek, Czechia
• ⁴Laboratory of Animal Evolutionary Biology, Faculty of Science, Department of Zoology, Charles University, Prague, Czechia

Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system (CNS). Animal models have shown that gut microbiota plays a crucial role in MS pathogenesis. Several human studies have shown the gut microbiota role in MS as well. To investigate the potential role of gut microbiota on treatment response, using 16S rRNA sequencing we analyzed the gut microbiota composition in treatment-naïve patients and those treated with one of the disease-modifying drugs (IFN-β, fingolimod and cladribine), comparing them to healthy controls (HC). Multiple sclerosis (MS) is a chronic autoimmune disorder of the central nervous system, with both animal and human studies highlighting a pivotal role for the gut microbiota in its pathogenesis. In this cross-sectional study, we investigated the potential role of gut microbiota in treatment response by analyzing its composition using 16S rRNA sequencing in treatment-naïve patients and those receiving disease-modifying therapies (IFN-βinterferon-beta (IFN-β), fingolimod, or cladribine), compared to healthy controls (HC). We also analyzed differences in gut microbiota composition and the serum levels of biomarkers associated with microbial translocation and inflammation based on treatment response. We found that newly individuals with clinically isolated syndrome (CIS)diagnosed treatment-naïve persons with multiple sclerosis (PwMS) and treatment non-responders (NR) had significantly different alpha and beta diversity compared to HC. This effect was present in both IFN-β and fingolimod treatment. PwMS Individuals treated with cladribine had significantly different alpha and beta diversity regardless of the treatment outcome. The main differences in abundances in newly diagnosed treatment-naïve PwMSCIS and NR were found in bacteria that produce short-chain fatty acids. These patients also had significantly higher levels of lipopolysaccharide-binding protein and mannose-binding lectin compared to HC suggesting the compromised gut barrier function in PwMS multiple sclerosis leading to higher level of microbial translocation in these patients. In summary, we found that the treatment influences the gutgut microbiota. Similar profile of gut microbiota and higher levels of molecules associated with microbial translocation were observed in patients with active disease (treatment naïve patientsCIS and NR), suggesting the higher permeability of their gut barrier leading to pro-inflammatory tunning of their immune system.