Apoptotic Cells In Kidney Research Articles

PROPHYLACTIC n CMT-3 ATTENUATES SEPSIS-INDUCED ACUTE KIDNEY INJURY IN ASSOCIATION WITH NLRP3 INFLAMMASOME ACTIVATION AND APOPTOSIS.

Background: The kidney is the most common extrapulmonary organ injured in sepsis. The current study examines the ability of aerosolized nanochemically modified tetracycline 3 (nCMT-3), a pleiotropic anti-inflammatory agent, to attenuate acute kidney injury (AKI) caused by intratracheal LPS. Methods: C57BL/6 mice received aerosolized intratracheal nCMT-3 (1 mg/kg) or saline, followed by intratracheal LPS (2.5 mg/kg) to induce acute lung injury-induced AKI. Tissues were harvested at 24 h. The effects of nCMT-3 and LPS on AKI were assessed by plasma/tissue levels of serum urea nitrogen, creatinine, neutrophil gelatinase-associated lipocalin, kidney injury molecule 1, and renal histology. Renal matrix metalloproteinase (MMP) level/activity, cytochrome C, Bax, Bcl-2, caspase-3, p38 mitogen-activated protein kinase activation, NLRP3, and caspase-1 were also measured. Apoptotic cells in kidney were determined by TUNEL assay. Renal levels of IL-1β and IL-6 were measured to assess inflammation. Results: Acute lung injury-induced AKI was characterized by increased plasma blood urea nitrogen, creatinine, injury biomarkers (neutrophil gelatinase-associated lipocalin, kidney injury molecule 1), and histologic evidence of renal injury. Lipopolysaccharide-treated mice demonstrated renal injury with increased levels of inflammatory cytokines (IL-1β, IL-6), active MMP-2 and MMP-9, proapoptotic proteins (cytochrome C, Bax/Bcl-2 ratio, cleaved caspase-3), apoptotic cells, inflammasome activation (NLRP3, caspase-1), and p38 signaling. Intratracheal nCMT-3 significantly attenuated all the measured markers of renal injury, inflammation, and apoptosis. Conclusions: Pretreatment with aerosolized nCMT-3 attenuates LPS-induced AKI by inhibiting renal NLRP3 inflammasome activation, renal inflammation, and apoptosis.

Protective effects of Panax notoginseng saponins on PME-Induced nephrotoxicity in mice

Polymyxin E (PME) plays an important role in fighting against Gram-negative bacterial infections; however, it causes nephrotoxicity, which limits its clinical use. The aim of this study was to investigate the protective effects of a plant extract Panax notoginseng saponins (PNS) on PME-induced nephrotoxicity in mice. In vivo studies showed that PNS significantly reduced blood urea nitrogen (BUN), serum creatinine (CRE) and number of apoptotic cells in kidney, as well as renal histopathological damage which increased in the presence of PME, and suppressed PME-induced oxidative stress in kidney, as shown by the up-regulation of superoxide dismutase (SOD) and the down-regulation of malondialdehyde (MDA) levels. Furthermore, PNS inhibited the expression of Bax, while increased the expression of Bcl-2 compared to the PME-treated group. In vitro studies showed that PNS decreased intracellular reactive oxygen species (ROS) and MDA levels, increased glutathione (GSH) levels, and enhanced the activity of SOD and glutathione peroxidase (GSH-Px) in murine renal tubular epithelial cells (TCMK-1 cells). In addition, PNS enhanced cell viability and the expression of Bcl-2, restored the mitochondrial membrane potential, inhibited the expression of Bax, inhibited the activity of caspase-3 and caspase-9, and reduce apoptotic rate in PME-treated TCMK-1 cells. PNS could reduce PME-induced nephrotoxicity. The protective effects could result from inhibition of oxidative stress, and prevention of cell apoptosis via the mitochondrial pathway. These findings highlight the potential of PNS as a safe adjunct for ameliorating the nephrotoxicity.

Non-erythropoietic erythropoietin-derived peptide protects mice from systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is an autoimmune disease, which results in various organ pathologies. However, current treatment towards SLE is suboptimal. Erythropoietin (EPO) has been shown to promote SLE recovery, but clinical application can be limited by its haematopoiesis‐stimulating effects. EPO‐derived helix‐B peptide (ARA290) is non‐erythrogenic but has been reported to retain the anti‐inflammatory and tissue‐protective functions of EPO. Therefore, here we investigated the effects and potential mechanisms of ARA290 on SLE. The administration of ARA290 to pristane‐induced SLE and MRL/lpr mice significantly suppressed the level of serum antinuclear autoantibodies (ANAs) and anti‐dsDNA autoantibodies, reduced the deposition of IgG and C3, and ameliorated the nephritis symptoms. Moreover, the serum concentrations of inflammatory cytokine IL‐6, MCP‐1 and TNF‐α in SLE mice were reduced by ARA290. Further, ARA290 decreased the number of apoptotic cells in kidney. In vitro experiment revealed that ARA290 inhibited the inflammatory activation of macrophages and promoted the phagocytotic function of macrophages to apoptotic cells. Finally, ARA290 did not induce haematopoiesis during treatment. In conclusion, ARA290 ameliorated SLE, which at least could be partly due to its anti‐inflammatory and apoptotic cell clearance promoting effects, without stimulating haematopoiesis, suggesting that ARA290 could be a hopeful candidate for SLE treatment.

Stevia and stevioside protect against cisplatin nephrotoxicity through inhibition of ERK1/2, STAT3, and NF-κB activation

We investigated the effect of natural sweetener Stevia rebaudiana and its constituent stevioside in cisplatin (CP)-induced kidney injury. Male BALB/cN mice were orally administered 10, 20, and 50 mg/kg body weight of Stevia rebaudiana ethanol extract (SE) or stevioside 50 mg/kg, 48 h after intraperitoneal administration of CP (13 mg/kg). Two days later, CP treatment resulted in histopathological changes showing kidney injury. Increased expression of 4-hydroxynonenal (4-HNE), 3-nitrotyrosine (3-NT), and heme oxygenase-1 (HO-1) in mice kidneys suggested oxidative stress. CP treatment also increased renal expression of nuclear factor-kappaB (NF-κB) p65 subunit and phosphorylated inhibitor of NF-κB (IκBα), as well as expression of pro-inflammatory cytokine tumor necrosis factor-alpha (TNF-α). Induction of apoptosis and inhibition of the cell cycle in kidneys was evidenced by increased expression of p53, Bax, caspase-9, and p21, proteolytic cleavage of poly (ADP-ribose) polymerase (PARP), with concomitant suppression of Bcl-2 and cyclin D1 expression. The number of apoptotic cells in kidneys was also assessed. CP administration resulted in activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) and signal transducer and activator of transcription 3 (STAT3). Both SE and stevioside attenuated CP nephrotoxicity by suppressing oxidative stress, inflammation, and apoptosis through mechanism involving ERK1/2, STAT3, and NF-κB suppression.

Ginsenoside-Rg1 inhibits endoplasmic reticulum stress-induced apoptosis after unilateral ureteral obstruction in rats

Aim: Endoplasmic reticulum (ER) stress and unfolded protein response (UPR) are implicated in many fibrotic diseases, including renal fibrosis. Whether Ginsenoside-Rg1 (G-Rg1) could attenuate renal fibrosis via suppression of ER stress and UPR has not been reported. The aim of this study was to explore the effect of G-Rg1 on ER stress and UPR-induced apoptosis in kidneys with unilateral ureteral obstruction (UUO) rat model. Methods: Twenty-four male Sprague–Dawley rats were randomly divided into control group, model group and G-Rg1 treatment group. G-Rg1 was administered to rats by intraperitoneal injection. Renal interstitial fibrosis in the model group was developed by UUO in rats. Renal function was estimated by the levels of serum creatinine (Scr) and blood urea nitrogen (BUN). Renal pathological damage was evaluated by hematoxylin and eosin (HE) and Masson’s trichrome staining. The ER stress was assessed with glucose-regulated protein (GRP) 78 expression, and the proapoptotic response was detected with CCAAT/enhancer-binding protein homologous protein (CHOP) and caspase-12 expressions by Western Blot. The number of apoptotic cells was determined by Terminal-deoxynucleotidyl Transferase Mediated Nick End Labeling (TUNEL) analysis. Results: UUO for 14 days aggravated renal function, renal damage and renal interstitial fibrosis, activated ER stress response (induction of GRP78 protein), enhanced the proapoptotic response (increase in CHOP and caspase-12 proteins) and increased the number of apoptotic cells (shown by the TUNEL assay). Treatment with G-Rg1 significantly ameliorates the renal pathological lesions and decreases expressions of ER stress-associated proteins and the level of apoptotic cells in kidneys. Conclusion: G-Rg1 suppresses renal cell apoptotic and fibrotic process partly through inhibition of ERS- and UPR-related apoptotic pathway in the kidneys after UUO.

Malarial Infection of Female BWF1 Lupus Mice Alters the Redox State in Kidney and Liver Tissues and Confers Protection against Lupus Nephritis

Systemic lupus erythematosus (SLE) is a prototypic autoimmune disease characterized by an imbalanced redox state and increased apoptosis. Tropical infections, particularly malaria, may confer protection against SLE. Oxidative stress is a hallmark of SLE. We have measured changes in the levels of nitric oxide (NO), hydrogen peroxide (H2O2), malondialdehyde (MDA), and reduced glutathione (GSH) in both kidney and liver tissues of female BWF1 lupus mice, an experimental model of SLE, after infection with either live or gamma-irradiated malaria. We observed a decrease in NO, H2O2, and MDA levels in kidney tissues after infection of lupus mice with live malaria. Similarly, the levels of NO and H2O2 were significantly decreased in the liver tissues of lupus mice after infection with live malaria. Conversely, GSH levels were obviously increased in both kidney and liver tissues after infection of lupus mice with either live or gamma-irradiated malaria. Liver and kidney functions were significantly altered after infection of lupus mice with live malaria. We further investigated the ultrastructural changes and detected the number of apoptotic cells in kidney and liver tissues in situ by electron microscopy and TUNEL assays. Our data reveal that infection of lupus mice with malaria confers protection against lupus nephritis.

Apoptosis in Kidney and Pancreas Allograft Biopsies

Apoptosis is a particular form of cell death involved in the elimination of somatic cells. In this study, the occurrence of apoptotic cells in kidney and pancreas allograft biopsies was analyzed and correlated with the number of infiltrating macrophages and lymphocytes and granzyme B expression. Kidney and pancreas biopsies from patients submitted to simultaneous pancreas-kidney transplantation were classified into three groups: acute rejection, chronic rejection, and transplant cases without evidence of rejection. Formalin-fixed paraffin biopsies were used to identify apoptosis by the terminal deoxynucleotidyl transferase [TdT]-mediated dUTP nick end labeling (TUNEL) method. In normal kidney, only few apoptotic cells were observed. In contrast, in kidney-allograft biopsies, the TUNEL signal was detected in the nuclei of tubular epithelial cells and also in mononuclear cells scattered in the interstitium. In pancreas biopsies, numerous apoptotic cells were detected in acinar cells, in ducts, and occasionally in islets. The number of apoptotic cells in acute pancreas rejection was significantly higher compared with acute rejection of kidney grafts (50+/-14 vs. 21+/-4 cells/mm2; P<0.05). In kidney biopsies, there was a positive correlation between apoptosis and macrophages (r=0.51; P<0.005), and apoptosis versus T lymphocytes (r=0.45; P<0.05). In pancreas biopsies, the number of apoptotic cells correlated only with the number of macrophages (r=0.41; P<0.05). Apoptosis occurs in kidney and pancreas allograft biopsies, markedly in acute rejection in pancreas biopsies. Although apoptosis may reflect a mechanism of down-regulation of the allograft immune response by eliminating infiltrating cells, the elimination of graft cells may result in graft damage, particularly in pancreas transplantation.

Impaired function of p53R2 in Rrm2b-null mice causes severe renal failure through attenuation of dNTP pools.

p53R2, which is regulated by tumor suppressor p53, is a small subunit of ribonucleotide reductase. To determine whether it is involved in DNA repair by supplying deoxyribonucleotides (dNTPs) for resting cells in vivo, we generated a strain of mice lacking Rrm2b (encoding p53R2). These mice developed normally until they were weaned but from then on had growth retardation and early mortality. Pathological examination indicated that multiple organs had failed, and all Rrm2b-null mice died from severe renal failure by the age of 14 weeks. TUNEL staining showed a greater number of apoptotic cells in kidneys of 8-week-old Rrm2b-/- mice relative to wild-type mice. p53 was activated in kidney tissues of Rrm2b-/- mice, leading to transcriptional induction of p53 target genes. Rrm2b-/- mouse embryonic fibroblasts (MEFs) became immortal much earlier than Rrm2b+/+ MEFs. dNTP pools were severely attenuated in Rrm2b-/- MEFs under oxidative stress. Rrm2b deficiency caused higher rates of spontaneous mutation in the kidneys of Rrm2b-/- mice. Our results suggest that p53R2 has a pivotal role in maintaining dNTP levels for repair of DNA in resting cells. Impairment of this pathway may enhance spontaneous mutation frequency and activate p53-dependent apoptotic pathway(s) in vivo, causing severe renal failure, growth retardation and early mortality.

Endothelial cell apoptosis during glomerular capillary lumen formation in vivo.

Transforming growth factor-beta (TGF-beta) stimulates endothelial cell apoptosis in vitro, and inhibition of TGF-beta1 leads to retention of undifferentiated endothelial cells in developing glomerular capillaries and reduced lumen formation in vivo. This study explored the question whether glomerular capillary lumen formation in vivo may involve TGF-beta1-dependent endothelial cell apoptosis. Neutralizing anti-TGF-beta1 or non-immune IgY were infused into the renal arteries of 3-d-old rats, and the kidneys were examined 2 d later. By transmission electron microscopy, endocapillary apoptotic cells were observed at a frequency of 0.10/loop in immature glomeruli of 3-d-old rat pups. In 5-d-old rat pups given neutralizing TGF-beta1 antibody or control IgY, the frequency of endocapillary apoptotic cells was 0.03 and 0.09/loop, respectively (P < 0.001, chi(2)). Dual labeling with TUNEL and anti-von Willebrand factor (vWF) antibody showed that apoptotic cells in immature glomeruli of 5-d-old rat pups are endothelial cells. Quantitative analysis showed significantly fewer TUNEL/vWF-labeled cells in glomeruli after anti-TGF-beta1 antibody infusion than in controls. No endocapillary apoptotic cells were observed in any group in C-shaped or S-shaped bodies, and the TUNEL assay revealed no glomerular apoptotic cells in kidneys from mature rats. These findings suggest that superfluous endothelial cells are cleared from immature glomerular capillaries by apoptosis, a process regulated by TGF-beta1. Taken together with the previous finding, that TGF-beta1 blockade blunts glomerular capillary lumen formation in vivo, it is proposed that TGF-beta1-dependent apoptosis serves to open capillary lumens in this vascular bed during glomerular development.

Determination of apoptotic cells in kidneys from non–heart-beating donors and heart-beating donors using the tunel assay: a limited immunohistochemical method?

Determination of apoptotic cells in kidneys from non–heart-beating donors and heart-beating donors using the tunel assay: a limited immunohistochemical method?