Search

A medical civic assistance program (MEDCAP) visit was conducted by naval reservists in eight villages in Senegal, West Africa. More than 6,000 patients were treated by MEDCAP team members. Medical and dental care, eyeglasses, vitamins, medications, educational material, and mass casualty training were provided. Major challenges confronting the mission were to provide care in makeshift clinics in remote villages in an arduous sub-Saharan climate, where more than one-half of the population lacks adequate public health funding to address basic medical and dental needs. To estimate the economic costs and benefits of the mission, as a guide to future planning, we calculated the total costs of the mission and its economic benefits. Total costs were found to be $502,500. We estimated that the monetary value of the medical services provided was $730,090. Additional nonquantifiable value was created through training and development of military and professional partnerships. In a post-September 11 world, the MEDCAP is an important and cost-effective vehicle to advance U.S. foreign policy in a nonthreatening manner. Countless lasting friendships can be won with bandages and medicines. [ABSTRACT FROM AUTHOR]

Long non-coding RNAs (lncRNAs) are a group of epigenetic regulators that have been implicated in kidney diseases including acute kidney injury (AKI). However, very little is known about the specific lncRNAs involved in AKI and the mechanisms underlying their pathologic roles. Here, we report a new lncRNA derived from the pseudogene GSTM3P1, which mediates ischemic AKI by interacting with and promoting the degradation of mir-668, a kidney-protective microRNA. GSTM3P1 and its mouse orthologue Gstm2-ps1 were induced by hypoxia in cultured kidney proximal tubular cells. In mouse kidneys, Gstm2-ps1 was significantly upregulated in proximal tubules at an early stage of ischemic AKI. This transient induction of Gstm2-ps1 depends on G3BP1, a key component in stress granules. GSTM3P1 overexpression increased kidney proximal tubular apoptosis after ATP depletion, which was rescued by mir-668. Notably, kidney proximal tubule-specific knockout of Gstm2-ps1 protected mice from ischemic AKI, as evidenced by improved kidney function, diminished tubular damage and apoptosis, and reduced kidney injury biomarker (NGAL) induction. To test the therapeutic potential, Gstm2-ps1 siRNAs were introduced into cultured mouse proximal tubular cells or administered to mice. In cultured cells, Gstm2-ps1 knockdown suppressed ATP depletion-associated apoptosis. In mice, Gstm2-ps1 knockdown ameliorated ischemic AKI. Mechanistically, both GSTM3P1 and Gstm2-ps1 possessed mir-668 binding sites and downregulated the mature form of mir-668. Specifically, GSTM3P1 directly bound to mature mir-668 to induce its decay via target-directed microRNA degradation. Thus, our results identify GSTM3P1 as a novel lncRNA that promotes kidney tubular cell death in AKI by binding mir-668 to inducing its degradation., (Copyright © 2024 International Society of Nephrology. All rights reserved.)

Macroautophagy/autophagy contributes to maladaptive kidney repair by inducing pro-fibrotic factors such as FGF2 (fibroblast growth factor 2), but the underlying mechanism remains elusive. Here, we show that EGR1 (early growth response 1) was induced in injured proximal tubules after ischemic acute kidney injury (AKI) and this induction was suppressed by autophagy deficiency in inducible, renal tubule-specific atg7 (autophagy related 7) knockout (iRT- atg7 KO) mice. In cultured proximal tubular cells, TGFB1 (transforming growth factor beta 1) induced EGR1 and this induction was also autophagy dependent. Egr1 knockdown in tubular cells reduced FGF2 expression during TGFB1 treatment, leading to less FGF2 secretion and decreased paracrine effects on fibroblasts. ChIP assay detected an increased binding of EGR1 to the Fgf2 gene promoter in TGFB1-treated tubular cells. Both Fgf2 and Egr1 transcription was inhibited by FGF2 neutralizing antibody, suggesting a positive feedback for EGR1-mediated FGF2 autoregulation. This feedback was confirmed using fgf2 -deficient tubular cells and fgf2 -deficient mice. Upstream of EGR1, autophagy deficiency in mice suppressed MAPK/ERK (mitogen-activated protein kinase) activation in post-ischemic renal tubules. This inhibition correlated with SQSTM1/p62 (sequestosome 1) aggregation and its sequestration of MAPK/ERK. SQSTM1/p62 interacted with MAPK/ERK and blocked its activation during TGFB1 treatment in autophagy-deficient tubular cells. Inhibition of MAPK/ERK suppressed EGR1 and FGF2 expression in maladaptive tubules, leading to the amelioration of renal fibrosis and improvement of renal function. These results suggest that autophagy activates MAPK/ERK in renal tubular cells, which induces EGR1 to transactivate FGF2. FGF2 is then secreted into the interstitium to stimulate fibroblasts for fibrogenesis. Abbreviation: 3-MA: 3-methyladenine; ACTA2/α-SMA: actin alpha 2, smooth muscle, aorta; ACTB/β-actin: actin, beta; AKI: acute kidney injury; aa: amino acid; ATG/ Atg : autophagy related; BUN: blood urea nitrogen; ChIP: chromatin immunoprecipitation; CKD: chronic kidney disease; CM: conditioned medium; COL1A1: collagen, type I, alpha 1; COL4A1: collagen, type IV, alpha 1; CQ: chloroquine; DBA: dolichos biflorus agglutinin; EGR1: early growth response 1; ELK1: ELK1, member of ETS oncogene family; FGF2: fibroblast growth factor 2; FN1: fibronectin 1; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; HAVCR1/KIM-1: hepatitis A virus cellular receptor 1; IP: immunoprecipitation; LIR: LC3-interacting region; MAP1LC3B/LC3B: microtubule-associated protein 1 light chain 3 beta; MAP2K/MEK: mitogen-activated protein kinase kinase; MAPK: mitogen-activated protein kinase; NFKB: nuclear factor kappa B; PB1: Phox and Bem1; PFT: pifithrin α; PPIB/cyclophilin B: peptidylprolyl isomerase B; RT-qPCR: real time-quantitative PCR; SQSTM1/p62: sequestosome 1; TGFB1/TGF-β1: transforming growth factor beta 1; VIM: vimentin.

The molecular basis of renal interstitial fibrosis, a major pathological feature of progressive kidney diseases, remains poorly understood. Autophagy has been implicated in renal fibrosis, but whether it promotes or inhibits fibrosis remains controversial. Moreover, it is unclear how autophagy is activated and sustained in renal fibrosis. The present study was designed to address these questions using the in vivo mouse model of unilateral ureteral obstruction and the in vitro model of hypoxia in renal tubular cells. Both models showed the activation of hypoxia-inducible factor-1 (HIF-1) and autophagy along with fibrotic changes. Inhibition of autophagy with chloroquine reduced renal fibrosis in unilateral ureteral obstruction model, whereas chloroquine and autophagy-related gene 7 knockdown decreased fibrotic changes in cultured renal proximal tubular cells, supporting a profibrotic role of autophagy. Notably, pharmacological and genetic inhibition of HIF-1 led to the suppression of autophagy and renal fibrosis in these models. Mechanistically, knock down of BCL2 and adenovirus E1B 19-kDa-interacting protein 3 ( BNIP3 ), a downstream target gene of HIF , decreased autophagy and fibrotic changes during hypoxia in BUMPT cells. Together, these results suggest that HIF-1 may activate autophagy via BNIP3 in renal tubular cells to facilitate the development of renal interstitial fibrosis. NEW & NOTEWORTHY Autophagy has been reported to participate in renal fibrosis, but its role and underlying activation mechanism is unclear. In this study, we report the role of HIF-1 in autophagy activation in models of renal fibrosis and further investigate the underlying mechanism.

Cisplatin is a widely used chemotherapy drug; however, it induces both acute and chronic kidney diseases (CKD) in patients with cancer. The pathogenesis of cisplatin-induced CKD is unclear, and effective renoprotective approaches are not available. Here, we report that repeated low-dose cisplatin (RLDC) treatment of C57BL/6 mice induced chronic cellular senescence in kidney tubules, accompanied with tubular degeneration and profibrotic phenotype transformation that culminated in maladaptive repair and renal fibrosis. Suppression of tubular senescence by senolytic drugs ABT-263 and Fisetin attenuated renal fibrosis and improved tubular repair, as indicated by restoration of tubular regeneration and renal function. In vitro, RLDC also induced senescence in mouse proximal tubular (BUMPT) cells. ABT-263 eliminated senescent BUMPT cells following RLDC treatment, reversed the profibrotic phenotype of the cells, and increased their clonogenic activity. Moreover, ABT-263 alleviated the paracrine effect of RLDC-treated BUMPT cells on fibroblasts for fibrosis. Consistently, knockdown of p16 suppressed post-RLDC senescence and fibrotic changes in BUMPT cells and alleviated their paracrine effects on renal fibroblast proliferation. These results indicate that persistent induction of tubular senescence plays an important role in promoting cisplatin-induced CKD. Targeting senescent tubular cells may be efficient for improvement of kidney repair and for the prevention and treatment of cisplatin-induced CKD.

Nephrotoxicity is a major side effect of cisplatin, a widely used cancer therapy drug. However, the mechanism of cisplatin nephrotoxicity remains unclear and no effective kidney protective strategies are available. Here, we report the induction of 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) in both in vitro cell culture and in vivo mouse models of cisplatin nephrotoxicity. Notably, PFKFB3 was mainly induced in the nucleus of kidney tubular cells, suggesting a novel function other than its canonical role in glycolysis. Both pharmacological inhibition and genetic silencing of PFKFB3 led to the suppression of cisplatin-induced apoptosis in cultured renal proximal tubular cells (RPTCs). Moreover, cisplatin-induced kidney injury or nephrotoxicity was ameliorated in renal proximal tubule-specific PFKFB3 knockout mice. Mechanistically, we demonstrated the interaction of PFKFB3 with cyclin-dependent kinase 4 (CDK4) during cisplatin treatment, resulting in CDK4 activation and consequent phosphorylation and inactivation of retinoblastoma tumor suppressor (Rb). Inhibition of CDK4 reduced cisplatin-induced apoptosis in RPTCs and kidney injury in mice. Collectively, this study unveils a novel pathological role of PFKFB3 in cisplatin nephrotoxicity through the activation of the CDK4/Rb pathway, suggesting a new kidney protective strategy for cancer patients by blocking PFKFB3., (Published by Elsevier Inc.)

Following acute kidney injury (AKI), renal tubular cells may stimulate fibroblasts in a paracrine fashion leading to interstitial fibrosis, but the paracrine factors and their regulation under this condition remain elusive. Here we identify a macroautophagy/autophagy-dependent FGF2 (fibroblast growth factor 2) production in tubular cells. Upon induction, FGF2 acts as a key paracrine factor to activate fibroblasts for renal fibrosis. After ischemic AKI in mice, autophagy activation persisted for weeks in renal tubular cells. In inducible, renal tubule-specific atg7 (autophagy related 7) knockout (iRT- atg7 -KO) mice, autophagy deficiency induced after AKI suppressed the pro-fibrotic phenotype in tubular cells and reduced fibrosis. Among the major cytokines, tubular autophagy deficiency in iRT- atg7 -KO mice specifically diminished FGF2. Autophagy inhibition also attenuated FGF2 expression in TGFB1/TGF-β1 (transforming growth factor, beta 1)-treated renal tubular cells. Consistent with a paracrine action, the culture medium of TGFB1-treated tubular cells stimulated renal fibroblasts, and this effect was suppressed by FGF2 neutralizing antibody and also by fgf2 - or atg7 -deletion in tubular cells. In human, compared with non-AKI, the renal biopsies from post-AKI patients had higher levels of autophagy and FGF2 in tubular cells, which showed significant correlations with renal fibrosis. These results indicate that persistent autophagy after AKI induces pro-fibrotic phenotype transformation in tubular cells leading to the expression and secretion of FGF2, which activates fibroblasts for renal fibrosis during maladaptive kidney repair. Abbreviations: 3-MA: 3-methyladnine; ACTA2/α-SMA: actin alpha 2, smooth muscle, aorta; ACTB/β-actin: actin, beta; AKI: acute kidney injury; ATG/ Atg : autophagy related; BUN: blood urea nitrogen; CCN2/CTGF: cellular communication network factor 2; CDKN2A/p16: cyclin dependent kinase inhibitor 2A; CKD: chronic kidney disease; CM: conditioned medium; COL1A1: collagen, type I, alpha 1; COL4A1: collagen, type IV, alpha 1; CQ: chloroquine; ECM: extracellular matrix; eGFR: estimated glomerular filtration rate; ELISA: enzyme-linked immunosorbent assay; FGF2: fibroblast growth factor 2; FN1: fibronectin 1; FOXO3: forkhead box O3; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; HAVCR1/KIM-1: hepatitis A virus cellular receptor 1; IHC: immunohistochemistry; IRI: ischemia-reperfusion injury; ISH: in situ hybridization; LTL: lotus tetragonolobus lectin; MAP1LC3B/LC3B: microtubule-associated protein 1 light chain 3 beta; MTOR: mechanistic target of rapamycin kinase; PDGFB: platelet derived growth factor, B polypeptide; PPIB/cyclophilin B: peptidylprolyl isomerase B; RT-qPCR: real time-quantitative PCR; SA-GLB1/β-gal: senescence-associated galactosidase, beta 1; SASP: senescence-associated secretory phenotype; sCr: serum creatinine; SQSTM1/p62: sequestosome 1; TASCC: TOR-autophagy spatial coupling compartment; TGFB1/TGF-β1: transforming growth factor, beta 1; VIM: vimentin.

Cisplatin is an effective chemotherapeutic agent for various solid tumours, but its use is limited by adverse effects in normal tissues. In particular, cisplatin is nephrotoxic and can cause acute kidney injury and chronic kidney disease. Preclinical studies have provided insights into the cellular and molecular mechanisms of cisplatin nephrotoxicity, which involve intracellular stresses including DNA damage, mitochondrial pathology, oxidative stress and endoplasmic reticulum stress. Stress responses, including autophagy, cell-cycle arrest, senescence, apoptosis, programmed necrosis and inflammation have key roles in the pathogenesis of cisplatin nephrotoxicity. In addition, emerging evidence suggests a contribution of epigenetic changes to cisplatin-induced acute kidney injury and chronic kidney disease. Further research is needed to determine how these pathways are integrated and to identify the cell type-specific roles of critical molecules involved in regulated necrosis, inflammation and epigenetic modifications in cisplatin nephrotoxicity. A number of potential therapeutic targets for cisplatin nephrotoxicity have been identified. However, the effects of renoprotective strategies on the efficacy of cisplatin chemotherapy needs to be thoroughly evaluated. Further research using tumour-bearing animals, multi-omics and genome-wide association studies will enable a comprehensive understanding of the complex cellular and molecular mechanisms of cisplatin nephrotoxicity and potentially lead to the identification of specific targets to protect the kidney without compromising the chemotherapeutic efficacy of cisplatin., (© 2022. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)

Diabetes may prevent kidney repair and sensitize the kidney to fibrosis or scar formation. To test this possibility, we examined renal fibrosis induced by unilateral ureteral obstruction (UUO) in diabetic mouse models. Indeed, UUO induced significantly more renal fibrosis in both Akita and STZ-induced diabetic mice than in nondiabetic mice. The diabetic mice also had more apoptosis and interstitial macrophage infiltration during UUO. In vitro, hypoxia induced higher expression of the fibrosis marker protein fibronectin in high glucose-conditioned renal tubular cells than in normal glucose cells. Mechanistically, hypoxia induced significantly more hypoxia-inducible factor-1 α (HIF-1 α) in high glucose cells than in normal glucose cells. Inhibition of HIF-1 attenuated the expression of fibronectin induced by hypoxia in high-glucose cells. Consistently, UUO induced significantly higher HIF-1α expression along with fibrosis in diabetic mice kidneys than in nondiabetic kidneys. The increased expression of fibrosis induced by UUO in diabetic mice was diminished in proximal tubule-HIF-1α-knockout mice. Together, these results indicate that diabetes sensitizes kidney tissues and cells to fibrogenesis probably by enhancing HIF-1 activation., (© 2022 Federation of American Societies for Experimental Biology.)

Kidney injury associated with cold storage/transplantation is a primary factor for delayed graft function and poor outcome of renal transplants. p53 contributes to both ischemic and nephrotoxic kidney injury, but its involvement in kidney cold storage/transplantation is unclear. Here, we report that p53 in kidney proximal tubules plays a critical role in cold storage/transplantation kidney injury and inhibition of p53 can effectively improve the histology and function of transplanted kidneys. In a mouse kidney cold storage/transplantation model, we detected p53 accumulation in proximal tubules in a cold storage time-dependent manner, which correlated with tubular injury and cell death. Pifithrin-α, a pharmacologic p53 inhibitor, could reduce acute tubular injury, apoptosis and inflammation at 24 h after cold storage/transplantation. Similar effects were shown by the ablation of p53 from proximal tubule cells. Notably, pifithrin-α also ameliorated kidney injury and improved the function of transplanted kidneys in 6 days when it became the sole life-supporting kidney in recipient mice. in vitro , cold storage followed by rewarming induced cell death in cultured proximal tubule cells, which was accompanied by p53 activation and suppressed by pifithrin-α and dominant-negative p53. Together, these results support a pathogenic role of p53 in cold storage/transplantation kidney injury and demonstrate the therapeutic potential of p53 inhibitors., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Xiang, Zhu, Zhang, Ma, Livingston and Dong.)

Tubular changes contribute to the development of renal pathologies in diabetic kidney disease (DKD), including interstitial fibrosis. It is unclear how tubular cells relay signals to interstitial fibroblasts. Recently, exosomes have been recognized as crucial mediators of intercellular communication. We hypothesized that exosomes secreted from tubular cells may stimulate fibroblasts for interstitial fibrosis in DKD. In this study, we isolated and purified exosomes from the renal cortex of DKD mice and high glucose-treated mouse proximal tubular cells. Compared with nondiabetic mice, exosome secretion in kidney tissues decreased in DKD mice. Likewise, high glucose incubation reduced exosome secretion in mouse kidney proximal tubular BUMPT cells. To study the effect of tubular cell exosomes on fibroblasts, exosomes from BUMPT cells were added to renal fibroblast NRK-49F cell cultures. Notably, exosomes from high glucose conditioned BUMPT cells induced higher proliferation, significant morphological change, and substantial production of fibronectin, α-smooth muscle actin, and collagen type Ι in NRK-49F fibroblasts. Proteomics analysis was further performed to profile the proteins within tubular cell exosomes. Interestingly, 22 proteins were found to be differentially expressed between tubular exosomes derived from high glucose conditioned cells and those from normal glucose conditioned cells. Cytoscape analysis suggested the existence of two protein-protein interaction networks in these exosomal differentially expressed proteins. While one of the protein-protein interaction networks comprised enolase 1 (Eno1), heat shock protein family A member 8 (Hspa8), thioredoxin 1 (Txn1), peptidylprolyl isomerase A (Ppia), phosphoglycerate kinase 1 (Pgk1), DNA topoisomerase II-β (Top2b), and β-actin (Actb), the other had the family proteins of human leucocyte antigen F (Ywhag), a component of the ND10 nuclear body (Ywhae), interferon regulatory factor-8 (Ywhaq), and human leucocyte antigen A (Ywhaz). Gene expression analysis via Nephroseq showed a correlation of Eno1 expression with DKD clinical manifestation. In conclusion, DKD is associated with a decrease in exosome secretion in renal tubular cells. Exosomes from high glucose conditioned tubular cells may regulate the proliferation and activation of fibroblasts, contributing to the paracrine signaling mechanism responsible for the pathological onset of renal interstitial fibrosis in DKD.

Dysregulation of autophagy in diabetic kidney disease (DKD) has been reported, but the underlying mechanism and its pathogenic role remain elusive. We show that autophagy was inhibited in DKD models and in human diabetic kidneys. Ablation of autophagy-related gene 7 (Atg7) from kidney proximal tubules led to autophagy deficiency and worse renal hypertrophy, tubular damage, inflammation, fibrosis, and albuminuria in diabetic mice, indicating a protective role of autophagy in DKD. Autophagy impairment in DKD was associated with the downregulation of unc-51-like autophagy-activating kinase 1 (ULK1), which was mediated by the upregulation of microRNA-214 (miR-214) in diabetic kidney cells and tissues. Ablation of miR-214 from kidney proximal tubules prevented a decrease in ULK1 expression and autophagy impairment in diabetic kidneys, resulting in less renal hypertrophy and albuminuria. Furthermore, blockade of p53 attenuated miR-214 induction in DKD, leading to higher levels of ULK1 and autophagy, accompanied by an amelioration of DKD. Compared with nondiabetic samples, renal biopsies from patients with diabetes showed induction of p53 and miR-214, associated with downregulation of ULK1 and autophagy. We found a positive correlation between p53/miR-214 and renal fibrosis, but a negative correlation between ULK1/LC3 and renal fibrosis in patients with diabetes. Together, these results identify the p53/miR-214/ULK1 axis in autophagy impairment in diabetic kidneys, pinpointing possible therapeutic targets for DKD.

Autophagy is a conserved lysosomal pathway for the degradation of cytoplasmic components. Basal autophagy in kidney cells is essential for the maintenance of kidney homeostasis, structure and function. Under stress conditions, autophagy is altered as part of the adaptive response of kidney cells, in a process that is tightly regulated by signalling pathways that can modulate the cellular autophagic flux - mammalian target of rapamycin, AMP-activated protein kinase and sirtuins are key regulators of autophagy. Dysregulated autophagy contributes to the pathogenesis of acute kidney injury, to incomplete kidney repair after acute kidney injury and to chronic kidney disease of varied aetiologies, including diabetic kidney disease, focal segmental glomerulosclerosis and polycystic kidney disease. Autophagy also has a role in kidney ageing. However, questions remain about whether autophagy has a protective or a pathological role in kidney fibrosis, and about the precise mechanisms and signalling pathways underlying the autophagy response in different types of kidney cells and across the spectrum of kidney diseases. Further research is needed to gain insights into the regulation of autophagy in the kidneys and to enable the discovery of pathway-specific and kidney-selective therapies for kidney diseases and anti-ageing strategies.

Mesenchymal stem cells (MSCs) have been proved to exert considerable therapeutic effects on ischemia-reperfusion (I/R)-induced injury, but the underlying mechanism remains unknown. In this study, we aimed to explore the potential molecular mechanism underlying the therapeutic effect of MSCs-derived exosome reinforced with miR-20a in reversing liver I/R injury. Quantitative real-time polymerase chain reaction, Western blot, and IHC were carried out to compare the differential expressions of miR-20a, Beclin-I, FAS, Caspase-3, mTOR and P62 in IR rats and normal rats. TUNEL was performed to assess IR-induced apoptosis in IR rats, and luciferase assay was used to confirm the inhibitory effect of miR-20a on Beclin-I and FAS expression. Among the 12 candidate microRNAs (miRNAs), miR-486, miR-25, miR-24, miR-20a,miR-466 and miR-433-3p were significantly downregulated in I/R. In particular, miR-20a, a miRNA highly expressed in umbilical cord-derived mesenchymal stem cells, was proved to bind to the 3' UTR of Beclin-I and FAS to exert an inhibitory effect on their expressions. Since Beclin-I and FAS were aberrantly upregulated in IR, exosomes separated from UC-MSCs showed therapeutic efficacy in reversing I/R induced apoptosis. In addition, exosomes reinforced with miR-20a and separated from UC-MSCs almost fully alleviated I/R injury. Furthermore, our results showed that miR-20a could alleviate the abnormal expression of genes related to apoptosis and autophagy, such as active Caspase-3, mTOR, P62, and LC3II. This study presented detailed evidence to clarify the mechanism underlying the therapeutic efficacy of UC-MSCs in the treatment of I/R injury., (© 2019 Wiley Periodicals, Inc.)

Ischemic preconditioning (IPC) affords tissue protection in organs including kidneys; however, the underlying mechanism remains unclear. Here we demonstrate an important role of macroautophagy/autophagy (especially mitophagy) in the protective effect of IPC in kidneys. IPC induced autophagy in renal tubular cells in mice and suppressed subsequent renal ischemia-reperfusion injury (IRI). The protective effect of IPC was abolished by pharmacological inhibitors of autophagy and by the ablation of Atg7 from kidney proximal tubules. Pretreatment with BECN1/Beclin1 peptide induced autophagy and protected against IRI. These results suggest the dependence of IPC protection on renal autophagy. During IPC, the mitophagy regulator PINK1 (PTEN induced putative kinase 1) was activated. Both IPC and BECN1 peptide enhanced mitolysosome formation during renal IRI in mitophagy reporter mice, suggesting that IPC may protect kidneys by activating mitophagy. We further established an in vitro model of IPC by inducing 'chemical ischemia' in kidney proximal tubular cells with carbonyl cyanide 3-chlorophenylhydrazone (CCCP). Brief treatment with CCCP protected against subsequent injury in these cells and the protective effect was abrogated by autophagy inhibition. In vitro IPC increased mitophagosome formation, enhanced the delivery of mitophagosomes to lysosomes, and promoted the clearance of damaged mitochondria during subsequent CCCP treatment. IPC also suppressed mitochondrial depolarization, improved ATP production, and inhibited the generation of reactive oxygen species. Knockdown of Pink1 suppressed mitophagy and reduced the cytoprotective effect of IPC. Together, these results suggest that autophagy, especially mitophagy, plays an important role in the protective effect of IPC. Abbreviations : ACTB: actin, beta; ATG: autophagy related; BNIP3: BCL2 interacting protein 3; BNIP3L/NIX: BCL2 interacting protein 3 like; BUN: blood urea nitrogen; CASP3: caspase 3; CCCP: carbonyl cyanide 3-chlorophenylhydrazone; COX4I1: cytochrome c oxidase subunit 4I1; COX8: cytochrome c oxidase subunit 8; DAPI: 4',6-diamidino-2-phenylindole; DNM1L: dynamin 1 like; EGFP: enhanced green fluorescent protein; EM: electron microscopy; ER: endoplasmic reticulum; FC: floxed control; FIS1: fission, mitochondrial 1; FUNDC1: FUN14 domain containing 1; H-E: hematoxylin-eosin; HIF1A: hypoxia inducible factor 1 subunit alpha; HSPD1: heat shock protein family D (Hsp60) member 1; IMMT/MIC60: inner membrane mitochondrial protein; IPC: ischemic preconditioning; I-R: ischemia-reperfusion; IRI: ischemia-reperfusion injury; JC-1: 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolylcarbocyanine iodide; KO: knockout; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; mito-QC: mito-quality control; mRFP: monomeric red fluorescent protein; NAC: N-acetylcysteine; PINK1: PTEN induced putative kinase 1; PPIB: peptidylprolyl isomerase B; PRKN: parkin RBR E3 ubiquitin protein ligase; ROS: reactive oxygen species; RPTC: rat proximal tubular cells; SD: standard deviation; sIPC: simulated IPC; SQSTM1/p62: sequestosome 1; TOMM20: translocase of outer mitochondrial membrane 20; TUNEL: terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling.

Renal fibrosis is the final common pathway of all chronic kidney diseases progressing to end-stage renal diseases. Autophagy, a highly conserved lysosomal degradation pathway, plays important roles in maintaining cellular homeostasis in all major types of kidney cells including renal tubular cells as well as podocytes, mesangial cells and endothelial cells in glomeruli. Autophagy dysfunction is implicated in the pathogenesis of various renal pathologies. Here, we analyze the pathological role and regulation of autophagy in renal fibrosis and related kidney diseases in both glomeruli and tubulointerstitial compartments. Further research is expected to gain significant mechanistic insights and discover pathway-specific and kidney-selective therapies targeting autophagy to prevent renal fibrosis and related kidney diseases.

The pathogenesis of ischemic diseases remains unclear. Here we demonstrate the induction of microRNA-668 (miR-668) in ischemic acute kidney injury (AKI) in human patients, mice, and renal tubular cells. The induction was HIF-1 dependent, as HIF-1 deficiency in cells and kidney proximal tubules attenuated miR-668 expression. We further identified a functional HIF-1 binding site in the miR-668 gene promoter. Anti-miR-668 increased apoptosis in renal tubular cells and enhanced ischemic AKI in mice, whereas miR-668 mimic was protective. Mechanistically, anti-miR-668 induced mitochondrial fragmentation, whereas miR-668 blocked mitochondrial fragmentation during hypoxia. We analyzed miR-668 target genes through immunoprecipitation of microRNA-induced silencing complexes followed by RNA deep sequencing and identified 124 protein-coding genes as likely targets of miR-668. Among these genes, only mitochondrial protein 18 kDa (MTP18) has been implicated in mitochondrial dynamics. In renal cells and mouse kidneys, miR-668 mimic suppressed MTP18, whereas anti-miR-668 increased MTP18 expression. Luciferase microRNA target reporter assay further verified MTP18 as a direct target of miR-668. In renal tubular cells, knockdown of MTP18 suppressed mitochondrial fragmentation and apoptosis. Together, the results suggest that miR-668 is induced via HIF-1 in ischemic AKI and that, upon induction, miR-668 represses MTP18 to preserve mitochondrial dynamics for renal tubular cell survival and kidney protection.

Histone deacetylase inhibitors (HDACi) have therapeutic effects in models of various renal diseases including acute kidney injury (AKI); however, the underlying mechanism remains unclear. Here we demonstrate that two widely tested HDACi (suberoylanilide hydroxamic acid (SAHA) and trichostatin A (TSA)) protect the kidneys in cisplatin-induced AKI by enhancing autophagy. In cultured renal proximal tubular cells, SAHA and TSA enhanced autophagy during cisplatin treatment. We further verified the protective effect of TSA against cisplatin-induced apoptosis in these cells. Notably, inhibition of autophagy by chloroquine or by autophagy gene 7 (Atg7) ablation diminished the protective effect of TSA. In mice, TSA increased autophagy in renal proximal tubules and protected against cisplatin-induced AKI. The in vivo effect of TSA was also abolished by chloroquine and by Atg7 knockout specifically from renal proximal tubules. Mechanistically, TSA stimulated AMPK and inactivated mTOR during cisplatin treatment of proximal tubule cells and kidneys in mice. Together, these results suggest that HDACi may protect kidneys by activating autophagy in proximal tubular cells.

Diabetic kidney disease, a leading cause of end-stage renal disease, has become a serious public health problem worldwide and lacks effective therapies. Autophagy is a highly conserved lysosomal degradation pathway that removes protein aggregates and damaged organelles to maintain cellular homeostasis. As important stress-responsive machinery, autophagy is involved in the pathogenesis of various diseases. Emerging evidence has suggested that dysregulated autophagy may contribute to both glomerular and tubulointerstitial pathologies in kidneys under diabetic conditions. This review summarizes the recent findings regarding the role of autophagy in the pathogenesis of diabetic kidney disease and highlights the regulation of autophagy by the nutrient-sensing pathways and intracellular stress signaling in this disease. The advances in our understanding of autophagy in diabetic kidney disease will facilitate the discovery of a new therapeutic target for the prevention and treatment of this life-threatening diabetes complication.

Podocytes are highly differentiated epithelial cells wrapping glomerular capillaries to form the filtration barrier in kidneys. As such, podocyte injury or dysfunction is a critical pathogenic event in glomerular disease. Autophagy plays an important role in the maintenance of the homeostasis and function of podocytes. However, it is less clear whether and how autophagy contributes to podocyte injury in glomerular disease. Here, we have examined the role of autophagy in adriamycin-induced nephropathy, a classic model of glomerular disease. We show that autophagy was induced by adriamycin in cultured podocytes in vitro and in podocytes in mice. In cultured podocytes, activation of autophagy with rapamycin led to the suppression of adriamycin-induced apoptosis, whereas inhibition of autophagy with chloroquine enhanced podocyte apoptosis during adriamycin treatment. To determine the role of autophagy in vivo, we established an inducible podocyte-specific autophagy-related gene 7 knockout mouse model (Podo-Atg7-KO). Compared with wild-type littermates, Podo-Atg7-KO mice showed higher levels of podocyte injury, glomerulopathy, and proteinuria during adriamycin treatment. Together, these observations support an important role of autophagy in protecting podocytes under the pathological conditions of glomerular disease, suggesting the therapeutic potential of autophagy induction.

Nephrotoxicity is a major adverse effect in cisplatin chemotherapy, and renoprotective approaches are unavailable. Recent work unveiled a critical role of protein kinase C δ (PKC δ ) in cisplatin nephrotoxicity and further demonstrated that inhibition of PKC δ not only protects kidneys but enhances the chemotherapeutic effect of cisplatin in tumors; however, the underlying mechanisms remain elusive. Here, we show that cisplatin induced rapid activation of autophagy in cultured kidney tubular cells and in the kidneys of injected mice. Cisplatin also induced the phosphorylation of mammalian target of rapamycin (mTOR), p70S6 kinase downstream of mTOR, and serine/threonine-protein kinase ULK1, a component of the autophagy initiating complex. In vitro , pharmacologic inhibition of mTOR, directly or through inhibition of AKT, enhanced autophagy after cisplatin treatment. Notably, in both cells and kidneys, blockade of PKC δ suppressed the cisplatin-induced phosphorylation of AKT, mTOR, p70S6 kinase, and ULK1 resulting in upregulation of autophagy. Furthermore, constitutively active and inactive forms of PKC δ respectively enhanced and suppressed cisplatin-induced apoptosis in cultured cells. In mechanistic studies, we showed coimmunoprecipitation of PKC δ and AKT from lysates of cisplatin-treated cells and direct phosphorylation of AKT at serine-473 by PKC δ in vitro Finally, administration of the PKC δ inhibitor rottlerin with cisplatin protected against cisplatin nephrotoxicity in wild-type mice, but not in renal autophagy-deficient mice. Together, these results reveal a pathway consisting of PKC δ , AKT, mTOR, and ULK1 that inhibits autophagy in cisplatin nephrotoxicity. PKC δ mediates cisplatin nephrotoxicity at least in part by suppressing autophagy, and accordingly, PKC δ inhibition protects kidneys by upregulating autophagy., (Copyright © 2017 by the American Society of Nephrology.)

Extracellular vesicles from stem cells or progenitor cells are novel therapeutic systems for acute kidney injury. With exosomes (the smallest class of extracellular vesicles), Viñas et al. successfully rescued ischemic injured kidney. MicroRNA-486-5p, the crucial factor specifically delivered by exosomes to kidney, ameliorates the injury by targeting phosphatase and tensin homolog and inhibiting endothelial cell apoptosis. In this commentary, we discuss the potential underlying mechanism and the pivotal impact of their study on extracellular vesicle therapy., (Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Renal fibrosis is the final, common pathway of end-stage renal disease. Whether and how autophagy contributes to renal fibrosis remains unclear. Here we first detected persistent autophagy in kidney proximal tubules in the renal fibrosis model of unilateral ureteral obstruction (UUO) in mice. UUO-associated fibrosis was suppressed by pharmacological inhibitors of autophagy and also by kidney proximal tubule-specific knockout of autophagy-related 7 (PT-Atg7 KO). Consistently, proliferation and activation of fibroblasts, as indicated by the expression of ACTA2/α-smooth muscle actin and VIM (vimentin), was inhibited in PT-Atg7 KO mice, so was the accumulation of extracellular matrix components including FN1 (fibronectin 1) and collagen fibrils. Tubular atrophy, apoptosis, nephron loss, and interstitial macrophage infiltration were all inhibited in these mice. Moreover, these mice showed a specific suppression of the expression of a profibrotic factor FGF2 (fibroblast growth factor 2). In vitro, TGFB1 (transforming growth factor β 1) induced autophagy, apoptosis, and FN1 accumulation in primary proximal tubular cells. Inhibition of autophagy suppressed FN1 accumulation and apoptosis, while enhancement of autophagy increased TGFB1-induced-cell death. These results suggest that persistent activation of autophagy in kidney proximal tubules promotes renal interstitial fibrosis during UUO. The profibrotic function of autophagy is related to the regulation on tubular cell death, interstitial inflammation, and the production of profibrotic factors.

Primary cilium is an organelle that plays significant roles in a number of cellular functions ranging from cell mechanosensation, proliferation, and differentiation to apoptosis. Autophagy is an evolutionarily conserved cellular function in biology and indispensable for cellular homeostasis. Both cilia and autophagy have been linked to different types of genetic and acquired human diseases. Their interaction has been suggested very recently, but the underlying mechanisms are still not fully understood. We examined autophagy in cells with suppressed cilia and measured cilium length in autophagy-activated or -suppressed cells. It was found that autophagy was repressed in cells with short cilia. Further investigation showed that MTOR activation was enhanced in cilia-suppressed cells and the MTOR inhibitor rapamycin could largely reverse autophagy suppression. In human kidney proximal tubular cells (HK2), autophagy induction was associated with cilium elongation. Conversely, autophagy inhibition by 3-methyladenine (3-MA) and chloroquine (CQ) as well as bafilomycin A1 (Baf) led to short cilia. Cilia were also shorter in cultured atg5-knockout (KO) cells and in atg7-KO kidney proximal tubular cells in mice. MG132, an inhibitor of the proteasome, could significantly restore cilium length in atg5-KO cells, being concomitant with the proteasome activity. Together, the results suggest that cilia and autophagy regulate reciprocally through the MTOR signaling pathway and ubiquitin-proteasome system.

Acute kidney injury is a major kidney disease associated with poor clinical outcomes. The pathogenesis of acute kidney injury is multifactorial and is characterized by tubular cell injury and death. Recent studies have shown autophagy induction in proximal tubular cells during acute kidney injury. The regulatory mechanisms of tubular cell autophagy are poorly understood; however, some recent findings have set up a foundation for further investigation. Although autophagy may promote cell death under certain experimental conditions, pharmacologic and autophagy-related gene knockout studies have established a renoprotective role for autophagy in acute kidney injury. The mechanisms by which autophagy protects cells from injury and how, possibly, its pro-survival role switches to pro-death under certain conditions are discussed. Further research is expected to help us understand the regulatory network of tubular cell autophagy, define its precise roles in the specific context of acute kidney injury, and identify autophagy-targeting strategies for the prevention and treatment of acute kidney injury., (© 2013 Elsevier Inc. All rights reserved.)

Acute kidney injury (AKI) is a major kidney disease associated with a poor clinical outcome both in the short and long term. Autophagy is a cellular stress response that plays important roles in the pathogenesis of various diseases. Autophagy is induced in proximal tubules during AKI. A renoprotective role of autophagy in AKI has been demonstrated by pharmacological and genetic inhibition studies. The role of autophagy in kidney recovery and repair from AKI, however, remains largely unknown. A dynamic change in autophagy during the recovery phase of AKI seems to be important for tubular proliferation and repair. In renal fibrosis, autophagy may either promote this via the induction of tubular atrophy and decomposition, or prevent it via effects on the intracellular degradation of excessive collagen. Further research is expected to improve the understanding of the regulation of autophagy in kidney injury and repair, elucidate the pathological roles of autophagy in renal fibrosis, and discover therapeutic targets for treating AKI and preventing its progression to chronic kidney disease., (2014 S. Karger AG, Basel.)

Objective: To estimate the cost of the extra time worked by Australian workers due to their co-workers' alcohol drinking., Design, Setting and Participants: A secondary analysis of data obtained from 1677 Australian workers aged 18 years or older collected as part of a broader national study into the third-party harms of alcohol. Computer-assisted telephone interviews were conducted between October and mid December 2008., Main Outcome Measures: Self-reported measures of the time spent covering for other people at work because of their alcohol drinking; measures of other impacts from co-workers' alcohol drinking; and self-reported income., Results: Around a third of Australian workers have experienced negative effects from their co-workers' alcohol drinking, with 3.5% of workers reporting having to work extra hours to cover for others. The total annual cost to the Australian economy of this extra work is estimated to be $453 million., Conclusions: The results of this study suggest that Australian workers are significantly affected by other people's alcohol drinking, at considerable cost. This finding highlights the significant cost to the workplace of alcohol consumption, extending previous work which has focused only on alcohol-related absenteeism.

Genetic models have been used to examine the evolution of insecticide resistance in pest species subject to data and assumptions regarding genetic, biological, and operational parameters. We used time-series data on pyrethroid tolerance and simple genetic models to estimate underlying genetic and biological parameters associated with resistance evolution in tobacco budworm, Heliothis virescens (F.), and bollworm, Helicoverpa zea (Boddie), Louisiana field populations. Assuming pyrethroid resistance is conferred by one gene at one locus in both species, inheritance of pyrethroid resistance was partially dominant in the tobacco budworm and partially recessive in the bollworm. Relative fitness estimates indicated that fitness costs associated with resistance selected against resistance alleles in the absence of selection pressure in the tobacco budworm, but not in the bollworm. In addition, relative fitness estimates obtained using the indirect method outlined in this study were similar in magnitude to estimates obtained using traditional direct approaches.

A comparison was made between the rate of iodide permeation of dentin by diffusion and by filtration. Before acid etching, filtration only doubled the rate of iodide permeation relative to that obtained by diffusion. After acid etching, filtration produced a 32-fold increase in permeation. Acid etching, by removing occluding debris, facilitates filtration more than diffusion.

A technique is described which permits measurements of the ease with which fluid permeates dentin. This value, the hydraulic conductance of dentin, increased as surface area increases and/or as dentin thickness decreases. It increased 32-fold when dentin was acid etched due to removal of surface debris occluding the tubules.

A simple in vitro method has been described for quantitatively measuring the rate at which isotopically labeled substances permeate through dentin in occlusal cavity preparations. The presence or absence of pulp tissue had only a minor effect on the kinetics of permeation. As the dentin was made thinner there was a resulting increase in the rate of iodide permeation. The relative rates of permeation were 3H2O greater than 131I greater than 99mTc greater than 14C-urea, a sequence that follows the molecular dimensions of these substances.

Iontophoretic currents (0--1.0 mA) were applied to dentin disks prepared from human third molars. A negative electrode increased 125I-permeation 10X, while a positive electrode increased 14C-lidocaine 8X. Iontophoresis appears promising as a method to increase the permeation of dentin by ionized substances of therapeutic interest.