Browsing by Author "Marambio-Ruiz, Lucas"
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- ItemHypertensive Nephropathy: Unveiling the Possible Involvement of Hemichannels and Pannexons(2022) Lucero, Claudia M.; Prieto Villalobos, Juan Carlos; Marambio-Ruiz, Lucas; Balmazabal, Javiera; Alvear Soto, Tanhia Francheska; Vega, Matías; Barra, Paola; Retamal, Mauricio A.; Orellana Roca, Juan Andrés; Gómez, Gonzalo I.Hypertension is one of the most common risk factors for developing chronic cardiovascular diseases, including hypertensive nephropathy. Within the glomerulus, hypertension causes damage and activation of mesangial cells (MCs), eliciting the production of large amounts of vasoactive and proinflammatory agents. Accordingly, the activation of AT1 receptors by the vasoactive molecule angiotensin II (AngII) contributes to the pathogenesis of renal damage, which is mediated mostly by the dysfunction of intracellular Ca2+ ([Ca2+]i) signaling. Similarly, inflammation entails complex processes, where [Ca2+]i also play crucial roles. Deregulation of this second messenger increases cell damage and promotes fibrosis, reduces renal blood flow, and impairs the glomerular filtration barrier. In vertebrates, [Ca2+]i signaling depends, in part, on the activity of two families of large-pore channels: hemichannels and pannexons. Interestingly, the opening of these channels depends on [Ca2+]i signaling. In this review, we propose that the opening of channels formed by connexins and/or pannexins mediated by AngII induces the ATP release to the extracellular media, with the subsequent activation of purinergic receptors. This process could elicit Ca2+ overload and constitute a feed-forward mechanism, leading to kidney damage.
- ItemTNF-α Plus IL-1β Induces Opposite Regulation of Cx43 Hemichannels and Gap Junctions in Mesangial Cells through a RhoA/ROCK-Dependent Pathway(2022) Lucero, Claudia M.; Marambio-Ruiz, Lucas; Balmazabal, Javiera; Prieto Villalobos, Juan Carlos; Leon, Marcelo; Fernandez, Paola; Orellana Roca, Juan Andrés; Velarde Aliaga, María Victoria; Saez, Juan C.; Gomez, Gonzalo, IConnexin 43 (Cx43) is expressed in kidney tissue where it forms hemichannels and gap junction channels. However, the possible functional relationship between these membrane channels and their role in damaged renal cells remains unknown. Here, analysis of ethidium uptake and thiobarbituric acid reactive species revealed that treatment with TNF-alpha plus IL-1 beta increases Cx43 hemichannel activity and oxidative stress in MES-13 cells (a cell line derived from mesangial cells), and in primary mesangial cells. The latter was also accompanied by a reduction in gap junctional communication, whereas Western blotting assays showed a progressive increase in phosphorylated MYPT (a target of RhoA/ROCK) and Cx43 upon TNF-alpha/IL-1 beta treatment. Additionally, inhibition of RhoA/ROCK strongly antagonized the TNF-alpha/IL-1 beta-induced activation of Cx43 hemichannels and reduction in gap junctional coupling. We propose that activation of Cx43 hemichannels and inhibition of cell-cell coupling during pro-inflammatory conditions could contribute to oxidative stress and damage of mesangial cells via the RhoA/ROCK pathway.