Dietary Gluten-Induced Gut Dysbiosis Is Accompanied by Selective Upregulation of microRNAs with Intestinal Tight Junction and Bacteria-Binding Motifs in Rhesus Macaque Model of Celiac Disease

Abstract

The composition of the gut microbiome reflects the overall health status of the host. In this study, stool samples representing the gut microbiomes from 6 gluten-sensitive (GS) captive juvenile rhesus macaques were compared with those from 6 healthy, age- and diet-matched peers. A total of 48 samples representing both groups were studied using V4 16S rRNA gene DNA analysis. Samples from GS macaques were further characterized based on type of diet administered: conventional monkey chow, i.e., wheat gluten-containing diet (GD), gluten-free diet (GFD), barley gluten-derived diet (BOMI) and reduced gluten barley-derived diet (RGB). It was hypothesized that the GD diet would lower the gut microbial diversity in GS macaques. This is the first report illustrating the reduction of gut microbial alpha-diversity (p < 0.05) following the consumption of dietary gluten in GS macaques. Selected bacterial families (e.g., Streptococcaceae and Lactobacillaceae) were enriched in GS macaques while Coriobacteriaceae was enriched in healthy animals. Within several weeks after the replacement of the GD by the GFD diet, the composition (beta-diversity) of gut microbiome in GS macaques started to change (p = 0.011) towards that of a normal macaque. Significance for alpha-diversity however, was not reached by the day 70 when the feeding experiment ended. Several inflammation-associated microRNAs (miR-203, -204, -23a, -23b and -29b) were upregulated (p < 0.05) in jejunum of 4 biopsied GS macaques fed GD with predicted binding sites on 16S ribosomal RNA of Lactobacillus reuteri (accession number: NR_025911), Prevotella stercorea (NR_041364) and Streptococcus luteciae (AJ297218) that were overrepresented in feces. Additionally, claudin-1, a validated tight junction protein target of miR-29b was significantly downregulated in jejunal epithelium of GS macaques. Taken together, we predict that with the introduction of effective treatments in future studies the diversity of gut microbiomes in GS macaques will approach those of healthy individuals. Further studies are needed to elucidate the regulatory pathways of inflammatory miRNAs in intestinal mucosa of GS macaques and to correlate their expression with gut dysbiosis.

Differential Hallmarks of Celiac Versus Non-Celiac Gluten Sensitivity

“…It was also shown that increased presence of some of the bacterial species involved in gluten metabolism leads to enteritis [13]. Our group recently demonstrated that Streptococcaceae and Lactobacillaceae families were enriched in GS rhesus macaque model of CD, while Coriobacteriaceae predominated in healthy animals [14]. In the future, studies to elucidate speciic dysbiotic pathways that distinguish NCGS from CD need to be done.…”

“…It has been reported that bacteria involved in gluten metabolism predominantly belong to phylum Firmicutes, in particular, those from the genus Lactobacillus, followed by Streptococcus, Staphylococcus, and Clostridia [13,14]. Recently, it was shown that GFD treatment signiicantly altered proportions of these bacterial groups and that restoration of normal bacterial lora took many months and possibly years [14,15].…”

“…Recently, it was shown that GFD treatment signiicantly altered proportions of these bacterial groups and that restoration of normal bacterial lora took many months and possibly years [14,15]. It was also shown that increased presence of some of the bacterial species involved in gluten metabolism leads to enteritis [13].…”

“…In addition, it is also likely that regulatory miRNAs secreted by host epithelial cells in response to dysbiotic events are also disease speciic. Recently, we identiied and reported several miRNAs (miR-203, miR-204, miR-23b, and miR-29b) with perfect complementarity between miRNA seed nucleotides (5′ prime nt position 2-7) and 16S rRNA sequence of dysbiotic bacterial species in the rhesus macaque model of CD (Figure 1) [14].…”

“…species complementary with dysbiotic bacterial species such as Streptococcus leuticeae (B) and others. It was proposed that intensity of such interactions can shape the gut microbiome dysbiosis either toward remission or relapse [14,16].…”