#2723 10-hydroxy-trans-2-decenoic and nonanoic acid delayed senescence in adult renal progenitor cells and increased the anti-aging Klotho protein secretion
Authors: Picerno Angela , Cicirelli Antonella , Giannuzzi Francesca , Montenegro Francesca , Maiullari Silvia , Sclavo Giorgia , Pontrelli Paola , Gesualdo Loreto , Sallustio Fabio 
Published: May 2024

Abstract

Background and Aims
Recent investigations have elucidated the complex system involving human adult renal stem/progenitor cells (ARPCs) and their pivotal role in maintaining homeostasis and in facilitating regenerative processes within the adult kidneys. CD133+/CD24+ ARPCs can repair several kinds of renal damage but their reparative properties can be compromised by the cell senescence, contributing to renal aging and impaired damage repair. The functional marker CD133 inversely correlates with cellular senescence and plays a crucial role in the ARPC regulation. Decreased protective factors, hypoxia, and microenvironmental stress drive increasingly cell senescence, disordered inflammation and renal fibrosis. The resulting fibrosis, senescence, and microvascular rarefaction exacerbate damage and promote chronic kidney disease (CKD) progression.
In this study, we explore the impact of natural molecular compounds and drugs on slowing down and delaying ARPC senescence.

Method
ARPCs were treated with the following compounds for 48 hours: nonanoic acid (1 mM), 3-decenoic acid (1 mM), 10-hydroxy-trans-2-decenoic acid (10-HDA, 25uM), and Valproic acid (VPA, 1 mM), either individually or in combination. Lipid microvesicles were used to transmit the bioactive molecules. FACS was used to determine the CD133 levels. the β-galactosidase assays were used to determine cell senescence status. Western blots were performed to assess p16, p53 and p21 markers.

Results
Cytofluorimetry results demonstrated an increase in the expression of CD133, the inverse cell senescence marker, both following stimulation with decenoic (fold change = 1.8, p = 0.0053) and nonanoic acid (FC = 1.3, p = 0.0056), and with VPA (FC 2, p = 0.0036). Simultaneously, the number of senescent cells decreased, as confirmed by the β-galactosidase assay (FC = 0.13, p = 0.0005). The treatment with decenoic and nonanoic acid also restored high levels of the lncRNA HOTAIR (FC = 14.6 for nonanoic acid and 12.7 for 10-HDA; p = 0.05), that in turn promoted the secretion of the α-Klotho anti-aging protein (FC = 3.1; p = 0.01). Additionally, the western blot analysis revealed that the 10-HDA decreased the expression of cell senescence markers, p16 (FC = 1.6, p = 0.05), p53 (FC = 1.8, p = 0.05) and p21 (FC= 3.7, p = 0.05). Moreover, the nonanoic acid reduced the expression of p16 (FC = 1.8, p = 0.05), p53 (FC = 2, p = 0.05) and p21 (FC= 2.6, p = 0.0007). Also, their combination contributes to decrease p16 (FC = 1.9, p = 0.05), p53 (FC = 1.3, p = 0.05) and p21 (FC= 2.5, p = 0.05).

Conclusion
This study identifies specific molecules capable of reducing or delaying ARPC senescence. In particular, the two natural compounds 10-HDA and nonanoic acid can also enhance the capacity of renal progenitors to secrete the α-Klotho protein whose decline prevention by several mechanisms can attenuate renal injuries, retard CKD progression, ameliorate extrarenal complications, and improve renal function. These findings present potential therapeutic avenues for delaying or mitigating the progression of CKD.