BACKGROUND Inadequate retinoid status has often been described as occurring with aging. Moreover, subclinical hypothyroid status has also been evoked in the elderly. Several studies performed in animals have described the crucial incidence of age-related hypo-functioning of retinoid and thyroid signalling pathways, particularly in the brain. OBJECTIVE The aim of the present study was to clari...

Retinoids are compounds with pleiotropic functions and a relatively selective targeting of certain skin structures. They are vitamins, because retinol (vitamin A) is not synthesized in the body and must be derived from diet, but also hormones with intracrine activity, because retinol is transformed into molecules that bind to nuclear receptors, exhibit their activity, and are subsequently inact...

In a search for retinoic acid (RA) receptor ligands endowed with potent apoptotic activity, a series of novel arotinoids were prepared. Because the stereochemistry of the C9-alkenyl portion of natural 9-cis-RA and the olefinic moiety of the previously synthesized isoxazole retinoid 4 seems to have particular importance for their apoptotic activity, novel retinoid analogues with a restricted or,...

BACKGROUND/AIM Vitamin A (all- trans -retinol, ATRol) serves as a precursor for all- trans -retinoic acid (ATRA), a ligand for the retinoic acid receptor (RAR), representing a potent regulator for many physiological processes. While murine melanoma cells are highly sensitive to retinoid treatment, human melanoma cells have developed still unidentified mechanisms that mediate cellular retinoid r...

The endogenous mechanism that determines vertebrate body length is unknown but must involve loss of chordo-neural-hinge (CNH)/axial stem cells and mesoderm progenitors in the tailbud. In early embryos, Fibroblast growth factor (FGF) maintains a cell pool that progressively generates the body and differentiation onset is driven by retinoid repression of FGF signalling. This raises the possibilit...

Estrogen receptor (KR)-positive human breast cancer cells are hormonally regulated and are inhibited by retinoids, whereas most ER-negative breast cancer cells arc not. Here, we compared retinoid-induced transcriptional activation and growth inhibition in the ER-negative breast cancer cell line \1DA-MB-231, stably transfected to express wild-type ER (S3Ü),with that of the ER-positive MCE-7 lin...

Acute promyelocytic leukemia (APL) is associated with chromosomal translocations involving RAR and its fusion partners including PML and PLZF. Using oligonucleotide arrays, we examined changes in global gene expression mediated by the ectopic expression of either PML/RAR (retinoid-sensitive) or PLZF/RAR (retinoid-resistant) in U937 cells. Of over 5000 genes analyzed, 16 genes were commonly upre...

Vitamin A (retinol) and provitamin A (beta-carotene) are metabolized to specific retinoid derivatives which function in either vision or growth and development. The metabolite 11-cis-retinal functions in light absorption for vision in chordate and nonchordate animals, whereas all-trans-retinoic acid and 9-cis-retinoic acid function as ligands for nuclear retinoic acid receptors that regulate ge...

Retinoids are morphogens and have been implicated in cell fate commitment of embryonic stem cells (ESCs) to neurons. Their effects are mediated by RAR and RXR nuclear receptors. However, transcriptional cofactors required for cell and gene-specific retinoid signaling are not known. Here we show that protein arginine methyl transferase (PRMT) 1 and 8 have key roles in determining retinoid regula...

The retinoid receptors have major roles throughout development, even in the absence of ligand. Here, we summarize an emerging theme whereby gene repression, mediated by unliganded retinoid receptors, can dictate cell fate. In addition to activating transcription, retinoid receptors actively repress gene transcription by recruiting cofactors that promote chromatin compaction. Two developmental p...