Saliva microbiome in primary Sjögren’s syndrome reveals distinct set of disease‐associated microbes

Abstract

Objective This study systematically aims to evaluate the salivary microbiome in patients with primary Sjögren's syndrome (pSS) using 16S rRNA sequencing approach. Methods DNA isolation and 16S rRNA sequencing was performed on saliva of 37 pSS and 35 control (CC) samples on HiSeq 2500 platform. 16S rRNA sequence analysis was performed independently using two popular computational pipelines, QIIME and less operational taxonomic units scripts (LoTuS). Results There were no significant changes in the alpha diversity between saliva of patients and controls. However, four genera including Bifidobacterium, Lactobacillus, Dialister and Leptotrichia were found to be differential between the two sets, and common between both QIIME and LoTuS analysis pipelines (Fold change of 2 and p < .05). Bifidobacterium, Dialister and Lactobacillus were found to be enriched, while Leptotrichia was significantly depleted in pSS compared to the controls. Exploration of microbial diversity measures (Chao1, observed species and Shannon index) revealed a significant increase in the diversity in patients with renal tubular acidosis. An opposite trend was noted, with depletion of diversity in patients with steroids. Conclusion Our analysis suggests that while no significant changes in the diversity of the salivary microbiome could be observed in Sjögren's syndrome compared to the controls, a set of four genera were significantly and consistently differential in the saliva of patients with pSS. Additionally, a difference in alpha diversity in patients with renal tubular acidosis and those on steroids was observed.

Epithelial–immune cell interplay in primary Sjögren syndrome salivary gland pathogenesis

“…Activation of TLRs that reco gnize components of bacteria (such as TLR1, TLR2 and TLR4) or viruses (such as TLR3, TLR7 and TLR9) on salivary gland ductal cells, for example, might repre sent a first step in the initiation of inflammation in the salivary gland in the early stages of disease. However, evidence that conclusively demonstrates the contribu tion of specific bacteria to salivary gland dysfunction in pSS is lacking [77][78][79][80][81] . Indeed, the most likely hypothesis is that alterations in the bacteriome in the oral cavity represent a consequence, rather than a cause, of salivary gland dysfunction in pSS 82 .…”

Interconnections between the Oral and Gut Microbiomes: Reversal of Microbial Dysbiosis and the Balance between Systemic Health and Disease

“…In patients with SLE, a decreased diversity of oral microbial species is illustrated by increased numbers of Selenomonas, T. denticola, Veillonella, and Leptotrichia that directly correlate with elevated levels of inflammatory cytokines IL-6, IL-17, and IL-33 [49]. In patients with primary SS, salivary Bifidobacterium, Dialister, and Lactobacillus levels were elevated, while Leptotrichia abundance was reduced [55]. Studies have also found lower Proteobacteria numbers and alpha diversity in the salivary microbiome of patients with SS and increased levels of Veillonella and Fusobacterium [51].…”

Dysbiotic oral microbiota and infected salivary glands in Sjögren’s syndrome

“…[9]. Dysbiosis of the oral microbiota in SS has been reported [10][11][12][13][14][15][16], but its connection to the etiopathogenesis of SS remains unclear. In addition, a recent study reported that the salivary microbiota of SS patients is comparable to that of non-SS sicca patients [17].…”