Current and Emerging Evidence for Toll-Like Receptor Activation in Sjögren’s Syndrome

Table 2

Aberrant TLR expression and activation in salivary tissue in SS.

Tissue/cell type	TLR	Results	Refs
pSS SGECs	1	(i) Increased gene expression compared to controls	[51]
Healthy and pSS SGECs	2	(i) TLR2 is expressed in SGECs; (ii) Increased protein expression following treatment with PGN; (iii) Upregulation of immune-activating molecules following TLR2 ligation; (iv) TLR2 activation induced IL-15 secretion	[50]; [51]; [66]; [52]
pSS MSG biopsies	2	(i) Increased protein expression compared to controls that correlates with the degree of salivary inflammation	[49]
Healthy and pSS SGECs	3	(i) TLR3 is expressed; (ii) Elevated gene expression compared to controls; (iii) Increased protein expression following treatment with poly(I:C); (iv) Upregulation of immune-activating molecules following TLR3 ligation	[50]; [51]; [66]; [74]
Healthy SGECs	3	(i) Induction of BAFF mRNA and protein secretion by the TLR3 agonists poly(I:C) and a dsRNA virus	[50]
Healthy and pSS SGECs	3	(i) Poly(I:C) treatment induced expression and activation of apoptosis-related signaling intermediates and anoikis	[74]; [66]; [73]
Healthy and pSS MSGs	3	(i) Increased protein expression of TLR3 signaling intermediate RIPK3 kinase in pSS tissue	[74]
SGECs	3	(i) Poly(I:C) treatment upregulated Ro52/TRIM21 mRNA, resulting in redistribution in nucleus	[76]
pSS MSG biopsies	4	(i) Increased protein expression compared to controls that correlates with the degree of salivary inflammation	[49]
Healthy and pSS SGECs	4	(i) Elevated gene expression compared to controls; (ii) Increased protein expression following LPS stimulation; (iii) Upregulation of immune-activating molecules following TLR4 ligation	[51]
A253 cells	4	(i) Increased protein expression following LPS stimulation; (ii) LPS-induced secretion of proinflammatory mediators	[62]
pSS MSG biopsies	6	(i) Increased protein expression compared to controls that correlates with the degree of salivary inflammation	[49]
Healthy SGECs	7	(i) TLR7 is expressed	[50]
pSS MSG biopsies	7	(i) TLR7 is expressed	[77]
Control and pSS parotid biopsies	7, 9	(i) Elevated protein expression	[78]
Healthy and pSS MSG biopsies	8, 9	(i) Elevated gene expression	[79]