scholarly journals Epithelial retinoic acid receptor β regulates serum amyloid A expression and vitamin A-dependent intestinal immunity

2019 ◽  
Author(s):  
Sureka Gattu ◽  
Ye-Ji Bang ◽  
Mihir Pendse ◽  
Chaitanya Dende ◽  
Andrew L. Chara ◽  
...  

AbstractVitamin A is a dietary component that is essential for the development of intestinal immunity. Vitamin A is absorbed and converted to its bioactive derivatives retinol and retinoic acid by the intestinal epithelium, yet little is known about how epithelial cells regulate vitamin A-dependent intestinal immunity. Here we show that epithelial cell expression of the transcription factor retinoic acid receptor β (RARβ) is essential for vitamin A-dependent intestinal immunity. Epithelial RARβ activated vitamin A-dependent expression of serum amyloid A (SAA) proteins by binding directly to Saa promoters. In accordance with the known role of SAAs in regulating Th17 cell effector function, epithelial RARβ promoted IL-17 production by intestinal Th17 cells. More broadly, epithelial RARβ was required for the development of key vitamin A-dependent adaptive immune responses, including CD4+ T cell homing to the intestine and the development of immunoglobulin A-producing intestinal B cells. Our findings provide insight into how the intestinal epithelium senses dietary vitamin A status to regulate adaptive immunity and highlight the role of epithelial cells in regulating intestinal immunity in response to diet.Significance StatementVitamin A is a nutrient that is essential for the development of intestinal immunity. It is absorbed by gut epithelial cells which convert it to retinol and retinoic acid. Here we show that the transcription factor retinoic acid receptor β (RARβ) allows epithelial cells to sense vitamin A in the diet and regulate vitamin A-dependent immunity in the intestine. We find that epithelial RARβ regulates several intestinal immune responses, including production of the immunomodulatory protein serum amyloid A, T cell homing to the intestine, and B cell production of immunoglobulin A. Our findings provide new insight into how epithelial cells sense vitamin A to regulate intestinal immunity and highlight why vitamin A is so important for immunity to infection.

2019 ◽  
Vol 116 (22) ◽  
pp. 10911-10916 ◽  
Author(s):  
Sureka Gattu ◽  
Ye-Ji Bang ◽  
Mihir Pendse ◽  
Chaitanya Dende ◽  
Andrew L. Chara ◽  
...  

Vitamin A is a dietary component that is essential for the development of intestinal immunity. Vitamin A is absorbed and converted to its bioactive derivatives retinol and retinoic acid by the intestinal epithelium, yet little is known about how epithelial cells regulate vitamin A-dependent intestinal immunity. Here we show that epithelial cell expression of the transcription factor retinoic acid receptor β (RARβ) is essential for vitamin A-dependent intestinal immunity. Epithelial RARβ activated vitamin A-dependent expression of serum amyloid A (SAA) proteins by binding directly to Saa promoters. In accordance with the known role of SAAs in regulating Th17 cell effector function, epithelial RARβ promoted IL-17 production by intestinal Th17 cells. More broadly, epithelial RARβ was required for the development of key vitamin A-dependent adaptive immune responses, including CD4+ T-cell homing to the intestine and the development of IgA-producing intestinal B cells. Our findings provide insight into how the intestinal epithelium senses dietary vitamin A status to regulate adaptive immunity, and highlight the role of epithelial cells in regulating intestinal immunity in response to diet.


1989 ◽  
Vol 11 (3) ◽  
pp. 1-6 ◽  
Author(s):  
Luigi M. De Luca ◽  
Elizabeth M. McDowell

In this paper we have suggested the new concept of exotrophic cells, i.e. cells that have conditionally escaped the need for an essential nutrient, such as vitamin A. These exotrophs might become fixed by a mutation and eventually contribute to the tumorigenic phenotype. The discovery of the retinoic acid receptor (RAR) has opened up new horizons in the search for the mechanism of action of retinoic acid [17; 18]. It is intriguing that a second retinoic acid receptor, RARE, is abundantly expressed in hepatoma tissue and not in normal liver; Benbrook et al. [191 suggest that the erroneous expression of the RARE might contribute to tumour development in liver. How and whether these findings relate to the vitamin-A-deficient status of hepatoma cells remains to be understood.


1992 ◽  
Vol 286 (3) ◽  
pp. 755-760 ◽  
Author(s):  
S Kato ◽  
H Mano ◽  
T Kumazawa ◽  
Y Yoshizawa ◽  
R Kojima ◽  
...  

We have investigated the effects of retinoids, vitamin D and thyroid hormone on the levels of retinoic acid receptor (RAR)alpha, RAR beta and RAR gamma mRNAs in intact animals. Although vitamin A deficiency caused no significant changes in the levels of RAR alpha and RAR gamma mRNAs, the level of RAR beta transcripts was greatly decreased in various tissues of vitamin A-deficient rats, but was restored rapidly to a normal level after administration of retinoic acid. Retinol also restored the RAR beta mRNA level, but the magnitude and kinetics of the induction differed from those by retinoic acid. The use of specific inhibitors demonstrated that this autoregulation of RAR beta gene expression in vivo occurred at the transcriptional level. In addition, from these results it was postulated that the maintenance of the normal RAR beta mRNA levels seemed to require a threshold serum retinol concentration (about 25 micrograms/dl). Moreover, we found that administration of retinol and retinoic acid to normal rats caused the overexpression of RAR beta transcripts (2-15-fold) when compared with the control levels of RAR beta mRNA, although the levels of RAR alpha and RAR gamma mRNAs were not affected. Vitamin D and thyroid hormone did not modulate the levels of RAR transcripts. These findings clearly indicate the specific ligand regulation of RAR beta gene expression in intact animals. The altered levels of RAR beta according to retinoid status may affect retinoid-inducible gene expression.


2009 ◽  
Vol 84 (2) ◽  
pp. 166-172 ◽  
Author(s):  
P. W. Kania ◽  
O. Evensen ◽  
T. B. Larsen ◽  
K. Buchmann

AbstractVarious strains of Atlantic salmon exhibit different levels of susceptibility to infections with the ectoparasitic monogenean Gyrodactylus salaris. The basic mechanisms involved in this differential ability to respond to this monogenean were elucidated using controlled and duplicated challenge experiments. Highly susceptible East Atlantic salmon allowed parasite populations to reach up to 3000 parasites per host within 6 weeks, whereas less susceptible Baltic salmon never reached larger parasite burdens than 122 parasites per host during the same period. The present study, comprising immunohistochemistry and gene expression analyses, showed that highly susceptible salmon erected a response mainly associated with an increased expression of interleukin-1β (IL-1β), interferon-γ (IFN-γ), IL-10 and infiltration of CD3-positive cells in the epidermis of infected fins. Less susceptible salmon showed no initial response in fins but 3–6 weeks post-infection a number of other genes (encoding the immune-regulating cytokine IL-10, cell marker MHC II and the pathogen-binding protein serum amyloid A) were found to be up-regulated. No proliferation of epithelial cells was seen in the skin of less susceptible salmon, and IL-10 may play a role in this regard. It can be hypothesized that resistant salmon regulate the parasite population by restricting nutrients (sloughed epithelial cells and associated material) and thereby starve the parasites. In association with this ‘scorched-earth strategy’, the production of pathogen-binding effector molecules such as serum amyloid A (SAA) (or others still not detected) may contribute to the resistance status of the fish during the later infection phases.


Development ◽  
1994 ◽  
Vol 120 (10) ◽  
pp. 2723-2748 ◽  
Author(s):  
D. Lohnes ◽  
M. Mark ◽  
C. Mendelsohn ◽  
P. Dolle ◽  
A. Dierich ◽  
...  

Numerous congenital malformations have been observed in fetuses of vitamin A-deficient (VAD) dams [Wilson, J. G., Roth, C. B., Warkany, J., (1953), Am. J. Anat. 92, 189–217]. Previous studies of retinoic acid receptor (RAR) mutant mice have not revealed any of these malformations [Li, E., Sucov, H. M., Lee, K.-F., Evans, R. M., Jaenisch, R. (1993) Proc. Natl. Acad. Sci. USA 90, 1590–1594; Lohnes, D., Kastner, P., Dierich, A., Mark, M., LeMeur, M., Chambon, P. (1993) Cell 73, 643–658; Lufkin, T., Lohnes, D., Mark, M., Dierich, A., Gorry, P., Gaub, M. P., Lemeur, M., Chambon, P. (1993) Proc. Natl. Acad. Sci. USA 90, 7225–7229; Mendelsohn, C., Mark, M., Dolle, P., Dierich, A., Gaub, M.P., Krust, A., Lampron, C., Chambon, P. (1994a) Dev. Biol. in press], suggesting either that there is a considerable functional redundancy among members of the RAR family during ontogenesis or that the RARs are not essential transducers of the retinoid signal in vivo. In order to discriminate between these possibilities, we have generated a series of RAR compound null mutants. These RAR double mutants invariably died either in utero or shortly after birth and presented a number of congenital abnormalities, which are reported in this and in the accompanying study. We describe here multiple eye abnormalities which are found in various RAR double mutant fetuses and are similar to those previously seen in VAD fetuses. Interestingly, we found further abnormalities not previously reported in VAD fetuses.(ABSTRACT TRUNCATED AT 250 WORDS)


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