High Concentration of C5a-Induced Mitochondria-Dependent Apoptosis in Murine Kidney Endothelial Cells

Abstract

Patients with a relapse of idiopathic nephrotic syndrome have significantly increased levels of serum complement component 5a (C5a), and proteinuria has been noted in mice treated with C5a via changes in permeability of kidney endothelial cells (KECs) in established animal models. However, the apoptosis of KECs treated with high concentrations of C5a has also been observed. As mitochondrial damage is known to be important in cell apoptosis, the aim of this study was to examine the association between C5a-induced mouse KEC apoptosis and mitochondrial damage. Mouse KECs were isolated and treated with different concentrations of C5a. Cell viability assays showed that a high-concentration mouse recombinant protein C5a (rmC5a) treatment reduced mouse KEC growth. Cell cycle phase analysis, including apoptosis (sub-G1 phase) showed an increased percentage of the subG1 phase with a high-concentration rmC5a treatment. Cytochrome c and caspase 3/9 activities were significantly induced in the mouse KECs after a high-dose rmC5a (50 ng/mL) treatment, and this was rescued by pretreatment with the C5a receptor (C5aR) inhibitor (W-54011) and N-acetylcysteine (NAC). Reactive oxygen species (ROS) formation was detected in C5a-treated mouse KECs; however, W-54011 or NAC pretreatment inhibited high-dose rmC5a-induced ROS formation and also reduced cytochrome c release, apoptotic cell formation, and apoptotic DNA fragmentation. These factors determined the apoptosis of mouse KECs treated with high-dose C5a through C5aR and subsequently led to apoptosis via ROS regeneration and cytochrome c release. The results showed that high concentrations of C5a induced mouse KEC apoptosis via a C5aR/ROS/mitochondria-dependent pathway. These findings may shed light on the potential mechanism of glomerular sclerosis, a process in idiopathic nephrotic syndrome causing renal function impairment.

Complement Regulation in Human Tenocytes under the Influence of Anaphylatoxin C5a

“…The C5 split fragment, C5a, is known to induce various inflammatory cell responses and has also been described as inducing apoptosis in adrenomedullary cells in an animal model of sepsis [ 15 , 22 ]. Additionally, a high concentration of 50 ng/mL recombinant C5a treatment of mouse kidney endothelial cells showed significantly higher rates of apoptosis than the lower concentrations or the control [ 23 ]. However, the vitality of human tenocytes exposed to concentrations of 25 ng/mL and 100 ng/mL C5a did not show significant changes; hence, cell vitality remained mainly unaffected.…”

“…However, the vitality of human tenocytes exposed to concentrations of 25 ng/mL and 100 ng/mL C5a did not show significant changes; hence, cell vitality remained mainly unaffected. The selected concentration of 25 ng/mL C5a is between that used in the above-mentioned study [ 23 ] and the C5a amount measured in human plasma (8.34 ± 2.05 ng/mL) [ 16 ]. This displays the rather robust nature of the human tenocytes when exposed to these concentrations of anaphylatoxin C5a for the whole treatment time period.…”

Complement C5 activation promotes type 2 diabetic kidney disease via activating STAT3 pathway and disrupting the gut‐kidney axis

“…(5 µmol/L, MedChemExpress) for 1 hour as previously described. 20,21 Afterwards, cells were stimulated with recombinant human C5a (50 nmol/L, Sino Biological Inc).…”

Natural products and phytochemical nanoformulations targeting mitochondria in oncotherapy: an updated review on resveratrol

“…Accumulating data demonstrates that mitochondria are the central gateway of the intrinsic pathway of apoptosis [79,80]. This reveals the potential role of mitochondria in the regulation of life and death [81,82]. The beginning point in the stimulation of apoptotic cell death by mitochondria is the release of cytochrome C (Cyt C) into the cytosol.…”