Modulation of Immunity and Inflammation by the Mineralocorticoid Receptor and Aldosterone.

The mineralocorticoid receptor (MR) is a ligand dependent transcription factor. MR has been traditionally associated with the control of water and electrolyte homeostasis in order to keep blood pressure through aldosterone activation. However, there is growing evidence indicating that MR expression is not restricted to vascular and renal tissues, as it can be also expressed by cells of the immune system, where it responds to stimulation or antagonism, controlling immune cell function. On the other hand, aldosterone also has been associated with proinflammatory immune effects, such as the release of proinflammatory cytokines, generating oxidative stress and inducing fibrosis. The inflammatory participation of MR and aldosterone in the cardiovascular disease suggests an association with alterations in the immune system. Hypertensive patients show higher levels of proinflammatory mediators that can be modulated by MR antagonism. Although these proinflammatory properties have been observed in other autoimmune and chronic inflammatory diseases, the cellular and molecular mechanisms that mediate these effects remain unknown. Here we review and discuss the scientific work aimed at determining the immunological role of MR and aldosterone in humans, as well as animal models.

Immune system alterations by aldosterone during hypertension: from clinical observations to genomic and non-genomic mechanisms leading to vascular damage.

Hypertension is traditionally considered a disease in which elevated blood pressure contributes to inflammation and activation of the immune system, leading to cardiovascular injury and end-organ damage. Here, we discuss the effects of aldosterone on the immune system and aldosterone's contribution to vascular pathogenesis. Studies in human have suggested a broader role for aldosterone, beyond elevating blood pressure. Recent clinical data support the notion that aldosterone can directly alter the function of the immune system and cause vascular-damaging inflammation. Clinical observations have been reproduced in experimental models of hypertension, further supporting the idea that an aberrant immune response contributes to the onset of hypertension. Such studies have shown that myeloid cells are required to induce the disease and IL-17-producing CD4(+) T cells may contribute to maintaining aldosterone-mediated hypertension. In addition, regulatory T cells diminish the inflammatory damage caused by aldosterone during hypertension. This is a very active area of research that could lead to new therapeutic targets for treating hypertension.

Mutations in FOXL2 underlying BPES (types 1 and 2) in Colombian families.

We report the genetic characterization of one family with blepharophimosis-ptosis-epicanthus inversus syndrome (BPES) type 1 and two families with BPES type 2 from a historically isolated population in northwest Colombia. Linkage and haplotype analyses indicate that BPES in these families is linked to 3q23. Mutation screening of FOXL2 in the family with BPES type 1 revealed a novel 394C --> T nonsense mutation which deletes the forkhead DNA binding domain. The two families with BPES type 2 both carry an in-frame 30 bp duplication that leads to the elongation of a polyalanine tract. This duplication has been previously reported in Europe, where recurrent mutation has been demonstrated in unrelated familial and sporadic BPES cases. The recurrent nature of this duplication seems to relate to the secondary structure of this DNA region. The genotype-phenotype correlation seen in the Colombian families is consistent with the recent proposal that BPES type 1 is caused by truncating mutations leading to haploinsufficiency, while BPES type 2 is due to mutations generating elongated protein products.