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.
Highlights
Serum complement component 5a (C5a) is a small soluble peptide fragment generated from complement cascade activation that regulates many inflammatory pathways, such as the degranulation of mast cells [1], neutrophil chemotaxis [2], and T lymphocyte infiltration [3]
CTh5aesReirnehsiublittsodreWm-o5n4s0t1r1ated priothr attoa hCi5gah dtroesaetmofeCnt5.a Tinhdeucreedsualptsoprteovseiasltehdrotuhgaht C550aRngo/nmmLouofserKmECC5sa. significantly induced cytochrome c release (Figure 3A) and caspase 3/9 activity (Figure 3B) in mouse kidney endothelial cells (KECs), whereas pretreatment with the C5a receptor (C5aR) inhibitor significantly rescued these induction effects (Figure 3). These results demonstrated that a high dose of C5a induced apoptosis through C5aR on mouse KECs
The inhibition of C5a, which can induce Reactive oxygen species (ROS) formation through the C5aR inhibitors (W-54011) or NAC, reduced cytochrome c release (Figure 5B), apoptotic cell formation (Figure 5C), and attenuated apoptotic DNA fragmentation (Figure 5D). These results indicated that a high dose of C5a may damage mouse KECs through C5aR/ROS/mitochondria-dependent apoptosis
Summary
Serum complement component 5a (C5a) is a small soluble peptide fragment generated from complement cascade activation that regulates many inflammatory pathways, such as the degranulation of mast cells [1], neutrophil chemotaxis [2], and T lymphocyte infiltration [3].
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
