1.
Silver jubilee: 25 years of the first demonstration of the direct effect of phosphate on the parathyroid cell.
Bover, J, Trinidad, P, Jara, A, Soler-Majoral, J, Martín-Malo, A, Torres, A, Frazão, J, Ureña, P, Dusso, A, Arana, C, et al
Nefrologia. 2022;(6):645-655
Abstract
Although phosphorus is an essential element for life, it is not found in nature in its native state but rather combined in the form of inorganic phosphates (PO43-), with tightly regulated plasma levels that are associated with deleterious effects and mortality when these are out of bounds. The growing interest in the accumulation of PO43- in human pathophysiology originated in its attributed role in the pathogenesis of secondary hyperparathyroidism (SHPT) in chronic kidney disease. In this article, we review the mechanisms by which this effect was justified and we commemorate the important contribution of a Spanish group led by Dr. M. Rodríguez, just 25 years ago, when they first demonstrated the direct effect of PO43- on the regulation of the synthesis and secretion of parathyroid hormone by maintaining the structural integrity of the parathyroid glands in their original experimental model. In addition to demonstrating the importance of arachidonic acid (AA) and the phospholipase A2-AA pathway as a mediator of parathyroid gland response, these findings were predecessors of the recent description of the important role of PO43- on the activity of the calcium sensor-receptor, and also fueled various lines of research on the importance of PO43- overload not only for the pathophysiology of SHPT but also in its systemic pathogenic role.
2.
Role of Nitrate Reductase in NO Production in Photosynthetic Eukaryotes.
Tejada-Jimenez, M, Llamas, A, Galván, A, Fernández, E
Plants (Basel, Switzerland). 2019;(3)
Abstract
Nitric oxide is a gaseous secondary messenger that is critical for proper cell signaling and plant survival when exposed to stress. Nitric oxide (NO) synthesis in plants, under standard phototrophic oxygenic conditions, has long been a very controversial issue. A few algal strains contain NO synthase (NOS), which appears to be absent in all other algae and land plants. The experimental data have led to the hypothesis that molybdoenzyme nitrate reductase (NR) is the main enzyme responsible for NO production in most plants. Recently, NR was found to be a necessary partner in a dual system that also includes another molybdoenzyme, which was renamed NO-forming nitrite reductase (NOFNiR). This enzyme produces NO independently of the molybdenum center of NR and depends on the NR electron transport chain from NAD(P)H to heme. Under the circumstances in which NR is not present or active, the existence of another NO-forming system that is similar to the NOS system would account for NO production and NO effects. PII protein, which senses and integrates the signals of the C⁻N balance in the cell, likely has an important role in organizing cell responses. Here, we critically analyze these topics.
3.
[Prevention and treatment of renal osteodystrophy: present and future].
Fernández, E, Craver, L
Nefrologia : publicacion oficial de la Sociedad Espanola Nefrologia. 2006;:19-27