Retinoid Receptors in Inflammatory Responses: A Potential Target for Pharmacology

While retinoids are largely used for their anti-proliferative and pro-differentiative effects, a rich body of literature suggests that retinoid nuclear receptors-related pathways can have profound influence on the outcome of immune and inflammatory reactions. Retinoid receptors related pathways modulate immune responses both at the innate and the adaptive level by altering skin barrier, neutrophil function, antibodies production, Th1 to Th2 shift, as well as induction of many regulatory cytokines. Retinoid X receptors (RXR) act functionally as homodimers or heterodimers with other members of the nuclear hormones receptor family such as retinoid acid receptors (RAR), vitamin D receptor (VDR), peroxisome proliferators activated receptor (PPAR) which are all associated with the regulation of inflammation and immunity. The existence of such heterodimers can provide a mechanism for cross-talk between hormone signalling pathways with a synergistic or additive activity on the anti-inflammatory outcome. This can be utilized in a variety of inflammatory skin disorders.