Angiotensin II-induced genomic damage in renal cells can be prevented by angiotensin II type 1 receptor blockage or radical scavenging

Abstract

Hypertensive patients exhibit elevated cancer incidence, especially of cancers of the kidney. Elevated levels of ANG II, the active peptide of the renin-angiotensin system, regulating blood pressure and cardiovascular homeostasis, are known to cause hypertension and kidney diseases. There is evidence that ANG II is an activator of NAD(P)H oxidase, leading to the formation of free radicals, which are known to participate in the induction of DNA damage. This study was undertaken to characterize ANG II-induced DNA damage. DNA damage was measured by comet assay and micronucleus frequency test. Incubation of pig kidney cells (LLC-PK(1)) in vitro with ANG II concentrations between 85 and 340 nM led to a 6- to 15-fold increase of DNA damage compared with the control as revealed by comet assay analysis. Micronuclei were induced about fourfold compared with the control in pig and rat kidney cells (LLC-PK(1), NRK) and in human promyelocytic cells (HL-60). ANG II-induced DNA damage could be prevented by coincubation with the ANG II type 1 receptor blocker candesartan and the antioxidants N-acetylcysteine and alpha-tocopherol. The ANG II type 2 receptor antagonist PD123319 could not reduce ANG II-induced DNA damage. Measurement of reactive oxygen species (ROS) by flow cytometry showed an enhanced formation after exposure to ANG II and a reduction of ROS after candesartan, N-acetylcysteine, and alpha-tocopherol. The present findings support our hypothesis that ANG II causes DNA damage via ANG II type 1 receptor binding and subsequent formation of oxidative stress.

Aldosterone Activates Transcription Factor Nrf2 in Kidney Cells both In Vitro and In Vivo

“…The comet assay was done as described earlier (50). Briefly, cells were treated for 4 and 24 h with the tested substances.…”

1,25-Dihydroxyvitamin D3 treatment delays cellular aging in human mesenchymal stem cells while maintaining their multipotent capacity

“…Cells were incubated with 30 mM H 2 DCF-DA for 45 min, trypsinized, and washed three times with PBS plus 1% BSA. The rate of oxidation was analyzed (3610 5 cells/sample) by flow cytometry using a BD LSR I (Becton Dickinson, Heidelberg, Germany) after incubation for 10 min on ice with 1 mg/ml propidium iodide, as described by Schupp et al [42]. The obtained data were evaluated with the CellQuest Pro software, by defining a region within the DCF-propidium iodide dot blot containing 2610 3 propidium iodide-negative cells.…”

Assessment of DNA Damage in Peripheral Blood Leukocytes of Patients with Essential Hypertension by the Alkaline Comet Assay

“…The damage may be resulting from the state of hypertensiveness via reactive oxygen species since these are both a consequence and cause of hypertension (Huie and Padmaja 1993). Angiotension II has also been found to be associated with free radical formation by activation of the NADPH oxidase enzyme that can cause DNA damage via Ang II type I receptor binding and the subsequent formation of oxidative stress (Schupp et al 2007). An increase in the level of 8-hydroxy guanine (8-OHdG) is also an indicator of the relationship between oxidative DNA damage, hypertension and cardiovascular disease risk (Negishi et al 2000).…”

“…It is a common chronic condition associated with reduced life expectancy with a potential to accumulate DNA damage (Pero et al 1976) probably resulting from reactive oxygen species (ROS) produced by xanthine oxidase, NADPH/NADH oxidases and nitric oxide synthetase which become increased in hypertension (Huie and Padmaja 1993). Also, the angiotension II gene has been found to be associated with free radicals formation (Schupp et al 2007). Free radicals react to form peroxynitrite which is a potent cytotoxic oxidant that leads to peroxidation of lipids, degradation of DNA and oligonucleosomal fragmentation (Hemnani and Parihar 1998).…”