Extracellular nucleotides from dying cells act as molecular signals to promote wound repair in renal tubular injury

2014 ◽  
Vol 307 (12) ◽  
pp. F1404-F1411 ◽  
Author(s):  
Shunsaku Nakagawa ◽  
Tomohiro Omura ◽  
Atsushi Yonezawa ◽  
Ikuko Yano ◽  
Takayuki Nakagawa ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Cell Death ◽  
Epithelial Cells ◽  
Wound Repair ◽  
Purinergic Signaling ◽  
Rat Kidney ◽  
Extracellular Nucleotides ◽  
Tubular Damage ◽  
Danger Signals ◽  
Renal Tubular

Acute kidney injury (AKI) often correlates with poor prognosis and is followed by various severe unfavorable systemic outcomes. It is important to understand the pathophysiology of AKI for the development of novel therapeutic approaches toward promoting renal regeneration after injury. Recent studies have indicated that AKI-induced tubular cell death plays an active role in the onset of tissue regeneration; however, the mechanisms underlying renal tubular repair after injury have yet to be understood. In the present study, we explored molecules that might serve as “danger” signals in mediating tubular regeneration. Kidneys of rats systemically administered the nephrotoxicant cisplatin (to induce AKI) exhibited massive cell proliferation. The proportion of proliferating cells in the total cell distribution was highest in the outer stripe of the outer medulla coincided with where the tubular damage was the most severe in this study. This finding suggests that soluble factors may have been released from damaged cells to stimulate the proliferation of neighboring tubular epithelial cells. In elucidating the mechanism of dying cell-to-surviving cell communication using normal rat kidney NRK-52E epithelial cells, we found a significant increase in ATP levels in supernatants of these cells after the induction of cell death using ultraviolet irradiation. Furthermore, treatment of conditioned supernatants with apyrase or suramin, which inhibits purinergic signaling, resulted in significant decreases in cell proliferation and migration activities. These results demonstrate a novel role for extracellular nucleotides, probably as danger signals in aggravating tubular regeneration after AKI.

Inhibition of tubular cell proliferation by neutralizing endogenous HGF leads to renal hypoxia and bone marrow-derived cell engraftment in acute renal failure

2008 ◽  
Vol 294 (2) ◽  
pp. F326-F335 ◽  
Author(s):  
Hiroyuki Ohnishi ◽  
Shinya Mizuno ◽  
Toshikazu Nakamura
Keyword(s):  
Bone Marrow ◽  
Cell Proliferation ◽  
Renal Failure ◽  
Acute Renal Failure ◽  
Repair Process ◽  
Tubular Cell ◽  
Tubular Damage ◽  
Renal Tubules ◽  
Stromal Cell Derived Factor ◽  
Renal Tubular

During the progression of acute renal failure (ARF), the renal tubular S3 segment is sensitive to ischemic stresses. For reversing tubular damage, resident tubular cells proliferate, and bone marrow-derived cells (BMDC) can be engrafted into injured tubules. However, how resident epithelium or BMDC are involved in tubular repair remains unknown. Using a mouse model of ARF, we examined whether hepatocyte growth factor (HGF) regulates a balance of resident cell proliferation and BMDC recruitment. Within 48 h post-renal ischemia, tubular destruction became evident, followed by two-waved regenerative events: 1) tubular cell proliferation between 2 and 4 days, along with an increase in blood HGF; and 2) appearance of BMDC in the tubules from 6 days postischemia. When anti-HGF IgG was injected in the earlier stage, tubular cell proliferation was inhibited, leading to an increase in BMDC in renal tubules. Under the HGF-neutralized state, stromal cell-derived factor-1 (SDF1) levels increased in renal tubules, associated with the enhanced hypoxia. Administrations of anti-SDF1 receptor IgG into ARF mice reduced the number of BMDC in interstitium and tubules. Thus possible cascades include 1) inhibition of tubular cell proliferation by neutralizing HGF leads to renal hypoxia and SDF1 upregulation; and 2) BMDC are eventually engrafted in tubules through SDF1-mediated chemotaxis. Inversely, administration of recombinant HGF suppressed the renal hypoxia, SDF1 upregulation, and BMDC engraftment in ARF mice by enhancing resident tubular cell proliferation. Thus we conclude that HGF is a positive regulator for eliciting resident tubular cell proliferation, and SDF1 for BMDC engraftment during the repair process of ARF.

Endogenous ATP release regulates Cl− secretion in cultured human and rat biliary epithelial cells

1999 ◽  
Vol 276 (6) ◽  
pp. G1391-G1400 ◽  
Author(s):  
Richard M. Roman ◽  
Andrew P. Feranchak ◽  
Kelli D. Salter ◽  
Yu Wang ◽  
J. Gregory Fitz
Keyword(s):  
Epithelial Cells ◽  
Cell Volume ◽  
Purinergic Signaling ◽  
Cell Volume Regulation ◽  
Atp Release ◽  
Extracellular Atp ◽  
Extracellular Nucleotides ◽  
Cell Swelling ◽  
Biliary Epithelial Cells ◽  
Normal Rat

P2Y receptor stimulation increases membrane Cl− permeability in biliary epithelial cells, but the source of extracellular nucleotides and physiological relevance of purinergic signaling to biliary secretion are unknown. Our objectives were to determine whether biliary cells release ATP under physiological conditions and whether extracellular ATP contributes to cell volume regulation and transepithelial secretion. With the use of a sensitive bioluminescence assay, constitutive ATP release was detected from human Mz-ChA-1 cholangiocarcinoma cells and polarized normal rat cholangiocyte monolayers. ATP release increased rapidly during cell swelling induced by hypotonic exposure. In Mz-ChA-1 cells, removal of extracellular ATP (apyrase) and P2 receptor blockade (suramin) reversibly inhibited whole cell Cl− current activation and prevented cell volume recovery during hypotonic stress. Moreover, exposure to apyrase induced cell swelling under isotonic conditions. In intact normal rat cholangiocyte monolayers, hypotonic perfusion activated apical Cl−currents, which were inhibited by addition of apyrase and suramin to bathing media. These findings indicate that modulation of ATP release by the cellular hydration state represents a potential signal coordinating cell volume with membrane Cl− permeability and transepithelial Cl−secretion.

Autophagy is associated with apoptosis in cisplatin injury to renal tubular epithelial cells

2008 ◽  
Vol 294 (4) ◽  
pp. F777-F787 ◽  
Author(s):  
Cheng Yang ◽  
Varsha Kaushal ◽  
Sudhir V. Shah ◽  
Gur P. Kaushal
Keyword(s):  
Cell Death ◽  
Epithelial Cells ◽  
Beclin 1 ◽  
Lag Phase ◽  
Tubular Epithelial Cells ◽  
Renal Tubular Epithelial Cells ◽  
Normal Cells ◽  
Life And Death ◽  
Renal Tubular ◽  
Induced Apoptosis

Autophagy has emerged as another major “programmed” mechanism to control life and death much like “programmed cell death” is for apoptosis in eukaryotes. We examined the expression of autophagic proteins and formation of autophagosomes during progression of cisplatin injury to renal tubular epithelial cells (RTEC). Autophagy was detected as early as 2–4 h after cisplatin exposure as indicated by induction of LC3-I, conversion of LC3-I to LC3-II protein, and upregulation of Beclin 1 and Atg5, essential markers of autophagy. The appearance of cisplatin-induced punctated staining of autophagosome-associated LC3-II upon GFP-LC3 transfection in RTEC provided further evidence for autophagy. The autophagy inhibitor 3-methyladenine blocked punctated staining of autophagosomes. The staining of normal cells with acridine orange displayed green fluorescence with cytoplasmic and nuclear components in normal cells but displayed considerable red fluorescence in cisplatin-treated cells, suggesting formation of numerous acidic autophagolysosomal vacuoles. Autophagy inhibitors LY294002 or 3-methyladenine or wortmannin inhibited the formation of autophagosomes but induced apoptosis after 2–4 h of cisplatin treatment as indicated by caspase-3/7 and -6 activation, nuclear fragmentation, and cell death. This switch from autophagy to apoptosis by autophagic inhibitors further suggests that the preapoptotic lag phase after treatment with cisplatin is mediated by autophagy. At later stages of cisplatin injury, apoptosis was also found to be associated with autophagy, as autophagic inhibitors and inactivation of autophagy proteins Beclin 1 and Atg5 enhanced activation of caspases and apoptosis. Our results demonstrate that induction of autophagy mounts an adaptive response, suppresses cisplatin-induced apoptosis, and prolongs survival of RTEC.

scholarly journals Novel lnc RNA regulated by HIF-1 inhibits apoptotic cell death in the renal tubular epithelial cells under hypoxia

2017 ◽  
Vol 5 (8) ◽  
pp. e13203 ◽  
Author(s):  
Imari Mimura ◽  
Yosuke Hirakawa ◽  
Yasuharu Kanki ◽  
Natsuki Kushida ◽  
Ryo Nakaki ◽  
...  
Keyword(s):  
Cell Death ◽  
Epithelial Cells ◽  
Apoptotic Cell ◽  
Apoptotic Cell Death ◽  
Tubular Epithelial Cells ◽  
Renal Tubular Epithelial Cells ◽  
Renal Tubular

Downregulation of SGK1 by nucleotides in renal tubular epithelial cells

2007 ◽  
Vol 293 (5) ◽  
pp. F1751-F1757 ◽  
Author(s):  
Liuzhe Li ◽  
Charles S. Wingo ◽  
Shen-Ling Xia
Keyword(s):  
Epithelial Cells ◽  
Purinergic Receptors ◽  
Kinase Activity ◽  
Purinergic Signaling ◽  
Collecting Duct ◽  
Collecting Duct Cells ◽  
Renal Collecting Duct ◽  
Renal Tubular ◽  
First Time ◽  
Dependent Pathway

This study determined whether nucleotides that bind to purinergic receptors (P2R) regulate the expression or function of serum- and glucocorticoid-inducible kinase-1 (SGK1) in mouse renal inner medullar collecting duct cells (mIMCD-3). The SGK1 protein was detected by Western blotting. A significant reduction of cytosolic SGK1 expression was observed in the cells pretreated with P2R agonist adenosine 5′- O-(3-thiotriphosphate) (ATPγS), and the reduction could be reversed by P2R antagonists. This reduction was also observed in cells that were pretreated with agonists for P2R subtypes. Using ELISA, we observed a reduced SGK1 kinase activity in ATPγS-pretreated cells. This effect was reversed by P2R antagonists. Furthermore, an increase of SGK1 kinase activity in aldosterone-pretreated cells was suppressed by ATPγS. These studies demonstrate for the first time that SGK1 can be downregulated by nucleotides in renal collecting duct epithelial cells, likely via the activation of P2R, and suggest that activation of renal purinergic signaling regulates a SGK1-dependent pathway that is known to modulate ion transport in the renal collecting duct.

Adult-onset calorie restriction delays the accumulation of mitochondrial enzyme abnormalities in aging rat kidney tubular epithelial cells

2007 ◽  
Vol 292 (6) ◽  
pp. F1751-F1760 ◽  
Author(s):  
Susan H. McKiernan ◽  
Victoria C. Tuen ◽  
Katherine Baldwin ◽  
Jonathan Wanagat ◽  
Arjang Djamali ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Calorie Restriction ◽  
Rat Kidney ◽  
Mitochondrial Enzyme ◽  
Tubular Epithelial Cells ◽  
Renal Tubular Epithelial Cells ◽  
Deletion Mutations ◽  
Aging Rat ◽  
Mtdna Deletion ◽  
Renal Tubular

Adult-onset calorie restriction (A-CR) is an experimental model of life extension and healthy aging less explored, compared with calorie restriction begun at early ages, but one more realistic for human application. We examined the effect of A-CR on the aging rat kidney with respect to common structural age-dependent changes and the accumulation of mitochondrial enzyme abnormalities in tubular epithelial cells. A 40% calorie restriction was initiated in middle-aged rats, before the onset of significant age-related changes in the Fischer × Brown Norway rat kidney. This dietary intervention effectively reduced glomerulosclerosis and tubular atrophy within 6 mo and changed the rate of interstitial fibrosis formation within 1 yr and vascular wall thickening and the expression cytochrome c oxidase (COX)-deficient tubular epithelial cells in 18 mo compared with age-matched ad libitum-fed rats. Our histological approach (histochemical staining for mitochondrial enzyme activity and laser capture microdissection) coupled with mitochondrial DNA (mtDNA) PCR analyses demonstrated that COX-deficient renal tubular epithelial cells accumulated mtDNA deletion mutations and that these cells contained unique, clonally expanded mtDNA deletion mutations. Renal tubular epithelial cells with mitochondrial abnormalities presented cellular characteristics indicative of physiological dysfunction.

scholarly journals Fluorofenidone Alleviates Renal Fibrosis by Inhibiting Necroptosis Through RIPK3/MLKL Pathway

2020 ◽  
Vol 11 ◽  
Author(s):  
Qin Dai ◽  
Yan Zhang ◽  
Xiaohua Liao ◽  
Yupeng Jiang ◽  
Xin Lv ◽  
...  
Keyword(s):  
Cell Death ◽  
Renal Fibrosis ◽  
Tissue Injury ◽  
Tubulointerstitial Fibrosis ◽  
Sterile Inflammation ◽  
Tubular Damage ◽  
Monocyte Chemoattractant Protein 1 ◽  
Renal Tubulointerstitial Fibrosis ◽  
Tnf Α ◽  
Renal Tubular

Cell death and sterile inflammation are major mechanisms of renal fibrosis, which eventually develop into end-stage renal disease. “Necroptosis” is a type of caspase-independent regulated cell death, and sterile inflammatory response caused by tissue injury is strongly related to necrosis. Fluorofenidone (AKF-PD) is a novel compound shown to ameliorate renal fibrosis and associated inflammation. We investigated whether AKF-PD could alleviate renal fibrosis by inhibiting necroptosis. Unilateral ureteral obstruction (UUO) was used to induce renal tubulointerstitial fibrosis in C57BL/6J mice. AKF-PD (500 mg/kg) or necrostatin-1 (Nec-1; 1.65 mg/kg) was administered simultaneously for 3 and 7 days. Obstructed kidneys and serum were harvested after euthanasia. AKF-PD and Nec-1 ameliorated renal tubular damage, inflammatory-cell infiltration, and collagen deposition, and the expression of proinflammatory factors (interlukin-1β, tumor necrosis factor [TNF]-α) and chemokines (monocyte chemoattractant protein-1) decreased. AKF-PD or Nec-1 treatment protected renal tubular epithelial cells from necrosis and reduced the release of lactate dehydrogenase in serum. Simultaneously, production of receptor-interacting protein kinase (RIPK)3 and mixed lineage kinase domain-like protein (MLKL) was also reduced 3 and 7 days after UUO. AKF-PD and Nec-1 significantly decreased the percentage of cell necrosis, inhibiting the phosphorylation of MLKL and RIPK3 in TNF-α- and Z-VAD–stimulated human proximal tubular epithelial (HK-2) cells. In conclusion, AKF-PD and Nec-1 have effective anti-inflammatory and antifibrotic activity in UUO-induced renal tubulointerstitial fibrosis, potentially mediated by the RIPK3/MLKL pathway.

scholarly journals Proliferation of Lung Epithelial Cells Is Regulated by the Mechanisms of Autophagy Upon Exposure of Soots

2021 ◽  
Vol 9 ◽  
Author(s):  
Rituraj Niranjan ◽  
Kaushal Prasad Mishra ◽  
Sachchida Nand Tripathi ◽  
Ashwani Kumar Thakur
Keyword(s):  
Cell Proliferation ◽  
Cell Death ◽  
Epithelial Cells ◽  
Antioxidant Properties ◽  
A549 Cells ◽  
Beclin 1 ◽  
Lung Epithelial Cells ◽  
Akt Inhibitor ◽  
Fullerene Soot ◽  
Lung Epithelial

BackgroundSoots are known to cause many diseases in humans, but their underlying mechanisms of toxicity are still not known. Here, we report that soots induce cell proliferation of lung epithelial cells via modulating autophagy pathways.ResultsFullerene soot and diesel exhaust particles (DEP) induced cell proliferation of lung epithelial, A549 cells via distinct autophagic mechanisms and did not cause cell death. Exposure of fullerene soot protected the cell death of A549 cells, caused by hydrogen peroxide, and inhibited LPS-induced autophagy. Fullerene soot co-localized with the autophagic proteins and inhibited starvation-induced autophagy (downregulated ATG-5, beclin-1, p62, and LC3 expressions) independent of its antioxidant properties. Similarly, it decreased the expression profile of autophagic genes and upregulated the proliferation-responsive gene, Ki-67, in mice. We observed that expressions of fullerene soot-responsive genes (Beclin-1, ATG-5, and p62) were reverted by Akt Inhibitor X, indicating an important role of the Akt pathway. At an elemental level, we found that elemental carbon of fullerene soot may be converted into organic carbon, as measured by OCEC, which may point fullerene soot as a source of carbon. On the other hand, DEP upregulated the expressions of autophagy genes. Akt Inhibitor X did not attenuate DEP-induced cell proliferation and autophagic response. However, an autophagic inhibitor, chloroquine, and significantly inhibited DEP-induced cell proliferation.ConclusionIt can be said that distinct autophagic mechanisms are operational in cell proliferation of lung epithelial cells due to soots, which may be responsible for different diseases. Understanding the mechanism of these pathways provides some important targets, which can be utilized for the development of future therapeutics.

scholarly journals Role of Ceramide Synthase in Oxidant Injury to Renal Tubular Epithelial Cells

2001 ◽  
Vol 12 (11) ◽  
pp. 2384-2391 ◽  
Author(s):  
NORISHI UEDA ◽  
SIMONE M. R. CAMARGO ◽  
XIAOMAN HONG ◽  
ALEXEI G. BASNAKIAN ◽  
PATRICK D. WALKER ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cell Death ◽  
Epithelial Cells ◽  
Oxidant Stress ◽  
Ceramide Synthase ◽  
Tubular Epithelial Cells ◽  
Renal Tubular Epithelial Cells ◽  
Renal Tubular ◽  
Ceramide Generation

Abstract. Ceramide has been implicated to play an important role in the cell signaling pathway involved in apoptosis. Most studies that have used the apoptotic model of cellular injury have suggested that enhanced ceramide generation is the result of the breakdown of sphingomyelin by sphingomyelinases. However, the role of ceramide synthase in enhanced ceramide generation in response to oxidant stress has not been previously examined in any tissue. Hydrogen peroxide (H2O2) (1 mM) resulted in a rapid increase in ceramide generation (as measured by in vitro diacylglycerol kinase assay) in LLC-PK1 cells. The intracellular ceramide level was significantly increased at 5 min after exposure of cells to H2O2 and thereafter continuously increased up to 60 min. H2O2 also resulted in a rapid increase (within 5 min) in ceramide synthase activity (as measured by incorporation of [14C] from the labeled palmytoyl—CoA into dihydroceramide) in microsomes. In contrast, the exposure of cells to H2O2 did not result in any significant change in sphingomyelin content or acid or neutral sphingomyelinase activity. An increase in ceramide production induced by H2O2 preceded any evidence of DNA damage and cell death. The specific inhibitor of ceramide synthase, fumonisin B1 (50 μM), was able to suppress H2O2-induced ceramide generation and provided a marked protection against H2O2-induced DNA strand breaks, DNA fragmentation, and cell death. Taken together, these data provide the first evidence that H2O2 is a regulator of ceramide synthase rather than sphingomyelinases and that ceramide synthase—dependent ceramide generation plays a key role in DNA damage and cell death in oxidant stress to renal tubular epithelial cells.

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