. 2023 May 16;14(11):824–860. doi: 10.1093/procel/pwad028

Table 1.

Sensors of microbial components in the intestine.

	Expression	Microbial signals	Diseases associated
TLR	–	–	–
TLR2	Enterocyte, GC, CSC, PC (Xiao et al., 2019); ENS; MC; TC; BC	LTA, peptidoglycan, lipoarabinomannan of bacteria; Lipopeptide/Lipoprotein of bacteria; Porin PorB of Neisseri (Reiser et al., 2017); Zymosan of fugus (Kataoka et al., 2002)	Mouse model
			Colitis	Watanabe et al. (2006), Podolsky et al. (2009), Brun et al. (2013), Scheeren et al. (2014), Kashiwagi et al. (2015), Mishima et al. (2019) and Jia et al. (2022)
			Neurological disorders	Brun et al. (2013) and Oppong et al. (2013)
			CRC	Scheeren et al. (2014) and Tsoi et al. (2017)
			Metabolic syndrome	Plovier et al. (2017) and Miani et al. (2018)
			Human study
			IBD	Pierik et al. (2006)
			PD	Gorecki et al. (2020)
TLR3	Enterocyte; MC; TC	dsRNA of virus	Mouse model
			Colitis	Kawashima et al. (2013) and Yang et al. (2016)
			Human study
			IBD	Cario and Podolsky (2000) and Yang et al. (2016)
			CRC	Castro et al. (2011)
TLR4	Enterocyte, GC, CSC; ENS; MC; TC; BC	LPS of Gram-negative bacteria	Mouse model
			Colitis	Fukata et al. (2005), Shi et al. (2006a), Chaniotou et al. (2010) and Yang et al. (2017)
			CRC	Kuo et al. (2015), Tsoi et al. (2017), Li et al. (2019b), Xiang et al. (2020) and Burgueño et al. (2021)
			Metabolic syndrome	Giles et al. (2017) and Chen et al. (2021a)
			Neurological disorders	Perez-Pardo et al. (2019)
			Human study
			PD	Zhao et al. (2015), Li et al. (2019d) and Perez-Pardo et al. (2019)
			CRC	Li et al. (2014)
TLR5	PC, CSC; DC	Flagellin of bacteria	Mouse model
			Metabolic syndrome	Vijay-Kumar et al. (2010), Chassaing et al. (2014), Singh et al. (2015) and Scheithauer et al. (2022)
			Rotavirus infection	Vijay-Kumar et al. (2008b) and Zhang et al. (2014a)
			Colitis	Lodes et al. (2004), Vijay-Kumar et al. (2007), Carvalho et al. (2012a, 2012c) and Chassaing et al. (2014)
			Human study
			IBD	Lodes et al. (2004)
			CRC	Beilmann-Lehtonen et al. (2021)
TLR7	Enterocyte; DC	ssRNA of virus	Mouse model
			Colitis	Sainathan et al. (2012), Yang et al. (2016) and McAlpine et al. (2018)
			Human study
			IBD	Yang et al. (2016)
TLR9	Enterocyte; ENS; MC	Non-methylated CpG DNA of bacteria and virus	Mouse model
			Colitis	Rachmilewitz et al. (2004), Obermeier et al. (2005) and Lee et al. (2006)
			CRC	Koo et al. (2015) and Luo et al. (2020)
			GVHD	Heimesaat et al. (2010)
			Human study
			CRC	Gao et al. (2018) and Messaritakis et al. (2022)
NLR	–	–	–
NOD1	IEC; mesothelial cell; MC; TC; BC	DAP-peptidoglycan of Gram-negative bacteria Certain Gram-positive bacteria (Hasegawa et al., 2006)	Mouse model
			Neurological disorders	Layunta et al. (2018) and Pusceddu et al. (2019)
			CRC	Jiang et al. (2020), Maisonneuve et al. (2021) and Wei et al. (2022)
NOD2	Enterocyte, CSC, PC, M, GC (Naama et al., 2023); MC (Magalhaes et al., 2008)	Phosphorylated-MDP of bacteria ssRNA of virus	Mouse model
			Ileitis/Colitis	Watanabe et al. (2006), Chu et al. (2016), Yadav et al. (2017) and Lin et al. (2020)
			CRC	Couturier-Maillard et al. (2013)
			Human study
			IBD	Hampe et al. (2001), Ogura et al. (2001), Cleynen et al. (2013), Liu et al. (2015a) and Yadav et al. (2017)
NLRP3	IEC; MC (Ruiz et al., 2017)	LPS of bacteria; Pore-forming toxins; Nucleic acids of bacteria and virus; Unfermented dietary β-fructan fibers	Mouse model
			Colitis	Bauer et al. (2010), Zaki et al. (2010) and Mehto et al. (2019)
			CAPS model	Lee et al. (2012) and Yao et al. (2017)
			Metabolic syndrome	Vandanmagsar et al. (2011) and Henao-Mejia et al. (2012)
			CRC	Allen et al. (2010), Guo et al. (2014), Qiao et al. (2020) and Shao et al. (2021)
			Human study
			IBD	Zhou et al. (2021)
			CAPS	Hoffman et al. (2001), Aksentijevich et al. (2002) and Feldmann et al. (2002)
NLRP6	Enterocyte (Xing et al., 2021), GC; MC (Anand et al., 2012)	RNA of virus; LTA and LPS of bacteria; Taurine, histamine, spermine, SCFAs	Mouse model
			Colitis	Elinav et al. (2011), Mukherjee et al. (2020) and Gao et al. (2023)
			Neuroinflammation	Li et al. (2019a), Matheis et al. (2020) and Muller et al. (2020)
			GVHD	Toubai et al. (2019)
			Metabolic syndrome	Henao-Mejia et al. (2012)
			Enterovirus infection	Wang et al. (2015a)
NLRP9b	Enterocyte	dsRNA of rotavirus	Mouse model
	Enterocyte	dsRNA of rotavirus	Rotavirus infection	Zhu et al. (2017b)
NLRP12	MC; TC (Lukens et al., 2015)	Ligands unknown Lachnospiraceae; Yersinia pestis (Vladimer et al., 2012); Brucella abortus (Silveira et al., 2017)	Mouse model
			Colitis	Zaki et al. (2011), Allen et al. (2012), Lukens et al. (2015) and Chen et al. (2017)
			CRC	Zaki et al. (2011) and Allen et al. (2012)
			Metabolic syndrome	Truax et al. (2018)
NLRC3	IEC; Mф; TC	dsDNA of HSV-1 (Li et al., 2019c)	Mouse model:
			Colitis	Karki et al. (2016)
			CRC	Karki et al. (2016, 2017)
NLRC4	IEC; MC	Flagellin, T3SS apparatus (rod protein) of bacteria	Mouse model
			Colitis	Carvalho et al. (2012b)
			Rotavirus infection	Zhang et al. (2014a)
			CRC	Allam et al. (2015)
			Human study
			IBD	Steiner et al. (2022)
			Metabolic syndrome	Furman et al. (2017)
RLR	Wide expression	–	–
RIG-1		5ʹ-Triphosphorylated RNA, Short-chain dsRNA of virus	Mouse model
			Colitis	Wang et al. (2007) and Liu et al. (2019)
			Rotavirus infection	Broquet et al. (2011) and Sen et al. (2011)
			CRC	Zhu et al. (2017a) and Song et al. (2022)
			GVHD	Fischer et al. (2017)
			Type 1 diabetes	Shigemoto et al. (2009)
MDA5		Long-chain dsRNA of virus	Mouse model
			Colitis	Ratsimandresy et al. (2017)
			Rotavirus infection	Broquet et al. (2011) and Sen et al. (2011)
			Type 1 diabetes	Smyth et al. (2006) and Shigemoto et al. (2009)
			Human study
			IBD	Huang et al. (2017) and Adiliaghdam et al. (2022)
–	–	–	–
AIM2	IEC; MC; TC (Chou et al., 2021); BC (Yang et al., 2021); RBC (Kalantari et al., 2014)	dsDNA of bacteria, virus and parasites	Mouse model
			Colitis	Ratsimandresy et al. (2017)
			Diabetes	Dang et al. (2017) and Leite et al. (2020)
			CRC	Man et al. (2015) and Wilson et al. (2015a)
			Human study
			IBD	Vanhove et al. (2015)
			CRC	Mori et al. (2001)
			SBC	Schulmann et al. (2005)
CLR	–	–	–
Dectin-1	IEC; Mф, DC, neu	β-Glucan of fungus	Mouse model
			Colitis	Heinsbroek et al. (2012), Iliev et al. (2012), Tang et al. (2015b) and Wang et al. (2022a)
			Human study
			UC	Iliev et al. (2012) and Sharifinejad et al. (2021)
Dectin-2	Mф (Yan et al., 2017), DC (Watanabe et al., 2023), neu	α-Mannan of fungus; Lipoglycans of bacteria	Mouse model
	Mф (Yan et al., 2017), DC (Watanabe et al., 2023), neu	α-Mannan of fungus; Lipoglycans of bacteria	Colitis	Duan et al. (2021) and Wang et al. (2022a)
SIGNR3	MC	Fugus; SLPA from Lactobacillus	Mouse model
	MC	Fugus; SLPA from Lactobacillus	Colitis	Eriksson et al. (2013) and Lightfoot et al. (2015)
CGAS/STING	Wide expression	DNA of bacteria; DNA of virus	Mouse model
			Intestine inflammation	Leibowitz et al. (2021), Shmuel-Galia et al. (2021) and Wang et al. (2022b)
			CRC	Hu et al. (2021) and Kunac et al. (2022)
			Obesity	Gao et al. (2022a)

IEC, intestine epithelial cell; PC, Paneth cell; GC, Goblet cell; CSC, crypt stem cell; M, M cell; MC, myeloid cell; Mф, macrophage; neu, neutrophil; ENS, enteric nervous system; DC, dentritic cell; TC, T cell; BC, B cell; RBC, red blood cell; CAPS: cryopyrin-associated periodic fever syndromes; SBC, small bowel cancer; GVHD, graft-versus-host disease; UC, ulcerative colitis; CRC, colorectal cancer; IBD, inflammatory bowel disease.