AT1R-Mediated Apoptosis of Bone Marrow Mesenchymal Stem Cells Is Associated with mtROS Production and mtDNA Reduction

Abstract

Angiotensin II (Ang II) is used as an inducer for the differentiation of mesenchymal stem cells (MSCs). Whether the commonly used doses of Ang II for MSC differentiation affect cell apoptosis has not been elucidated. In this study, we investigated the effect of Ang II on the apoptosis of bone marrow MSCs (BMMSCs), and its relations to the activation of Ang II receptor-1- (AT1R-) signaling, mitochondrial ROS (mtROS) generation, and mitochondrial DNA (mtDNA) leakage. AT1R expression in BMMSCs was identified by immunostaining and Western-blotting assays. BMMSC viability was measured by MTT assay following exposure to 1 nM~1 mM Ang II for 12 hours. Cell apoptosis, mtROS, and mtDNA levels were detected by FAM-FLICA® Poly Caspase, MitoSOX™ superoxide, and PicoGreen staining, respectively. The expressions of Bcl2 and Bax were measured by Western-blotting assays. Next, we used losartan to block AT1R-signaling and subsequently measured apoptosis, mtROS, and mtDNA levels, again. The maximum viability of BMMSCs was in response to 100 nM Ang II, after that it began to decrease with the increase of Ang II doses, indicating that Ang II (≧1 μM) may cause apoptosis of BMMSCs. As expected, 1 μM and 10 μM Ang II both caused BMMSC apoptosis. Furthermore, 1 μM and 10 μM Ang II could also induce mtROS generation and cause a marked mtDNA leakage. The application of losartan markedly inhibited Ang II-induced mtROS production, mtDNA leakage, and BMMSC apoptosis. In conclusion, the activation of AT1R-signaling stimulates apoptosis of BMMSCs, which is associated mtROS production and mtDNA reduction.

Azilsartan Suppresses Osteoclastogenesis and Ameliorates Ovariectomy-Induced Osteoporosis by Inhibiting Reactive Oxygen Species Production and Activating Nrf2 Signaling

“…Ang II and its receptor (AT1R) have been reported to induce NADPH oxidase (NOX)-dependent oxidative stress, generating ROS in osteoclasts (Nguyen Dinh Cat et al, 2013;Zhang et al, 2019;Zhou et al, 2020). In our present study, we found that azilsartan, an AT1R blocker, suppressed intramitochondrial and intracellular ROS production in osteoclasts.…”

“…Angiotensin (Ang) II, an octapeptide component of the reninangiotensin system (RAS), exerts its effects through two pharmacologically different G protein-coupled receptors: AT1R and AT2R (de Cavanagh et al, 2004;Benigni et al, 2010). Previous studies have documented the local expression of AT1R in the skeletal system of humans and animals (Zhang et al, 2019). Several components of the RAS, such as AT1R, AT2R, and ACE, are upregulated in mouse calvarial tissue during titanium-induced osteolysis (Zhao et al, 2021).…”

Tissue Renin‐Angiotensin System (tRAS) Induce Intervertebral Disc Degeneration by Activating Oxidative Stress and Inflammatory Reaction

“…ROS level frequently indicates intracellular oxidative conditions. Previous studies have revealed that Ang II could induce the release of reactive oxygen species (ROS) in cardiovascular diseases [ 28 ]. During IDD, excessive production of intracellular ROS will accelerate NP cell damage and inflammatory response [ 2 ].…”

An Insight on Multicentric Signaling of Angiotensin II in Cardiovascular system: A Recent Update

“…Ang II could increase mitochondrial ROS through the activation of Nox2. In a study, Ang II at the dose of 1 and 10 μM leads to apoptosis in bone marrow-derived MSCs due to mitochondrial ROS production and mitochondrial DNA leakage mediated via AT 1 R. Treatment with AT 1 R inhibitor, losartan, markedly inhibited the Ang II-induced apoptosis and mitochondrial ROS ( Zhang F. et al, 2019 ). Ang II production by cleaving enzyme chymase is several times higher in bone marrow than in other tissues.…”