Cisplatin-induced macroautophagy occurs prior to apoptosis in proximal tubules in vivo

Background

Autophagy is an intracellular bulk degradation process induced by cell starvation. Autophagy was recently reported to be induced by various stresses such as hypoxia, ischemia/reperfusion, toxins, and denatured proteins, and to affect cell survival and death. Light chain 3-II (LC3-II) is specifically located on double membrane-bound autophagosomes that envelop disused proteins or organelles.

Method

Transgenic mice in which green fluorescent protein (GFP) was fused to LC3 (LC3-GFP) were administered cisplatin (20 mg/kg). After euthanasia at times between 0 and 72 h, kidneys were excised for immunohistochemical analyses. Microscopic examinations of the generated NRK-52E cell lines stably transfected with LC3-GFP, and Western blot analyses of NRK-52E cells, were undertaken after cisplatin treatment with or without autophagy inhibitors and beclin 1 small interfering RNA (siRNA).

Results

Autophagosomes increased in the proximal tubular cells of transgenic mice from 12 h after cisplatin injection (20 mg/kg). The time course for this was faster than those for tubular necrosis and apoptosis. Autophagosomes also increased in NRK-52E cells after cisplatin treatment, with the time course for this being faster than that for apoptosis. When autophagy was suppressed by autophagy inhibitors or beclin 1 siRNA, the level of apoptosis was also suppressed.

Conclusion

Autophagy occurs in proximal tubular cells after cisplatin treatment and is involved in cell death in renal tubular injury. Our data suggest that autophagy is a kind of cell damage index and that cells with activated autophagy will be scavenged by apoptosis.     

Apogossypolone, a novel inhibitor of anfiapoptotic Bcl-2 family proteins, induces autophagy of PC-3 and LNCaP prostate cancer cells in vitro

Limited treatment options are available for aggressive prostate cancer. Gossypol has been reported to have a potent anticancer activity in many types of cancer. It can increase the sensitivity of cancer cells to alkylating agents, diminish multidrug resistance and decrease metastasis. Whether or not it can induce autophagy in cancer cells has not yet been determined. Here we investigated the antiproliferative activity of apogossypolone （ApoG2） and （-）-gossypol on the human prostate cancer cell line PC3 and LNCaP in vitro. Exposure of PC-3 and LNCaP cells to ApoG2 resulted in several specific features characteristic of autophagy, including the appearance of membranous vacuoles in the cytoplasm and formation of acidic vesicular organelles. Expression of autophagy-associated LC3-Ⅱ and beclin-1 increased in both cell lines after treatment. Inhibition of autophagy with 3-methyladenine promoted apoptosis of both cell types. Taken together, these data demonstrated that induction of autophagy could represent a defense mechanism against apoptosis in human prostate cancer cells.     

Dynamic changes of autophagy during hypertrophic scar formation and the role of autophagy intervention

BackgroundThe role of autophagy in the formation of hypertrophic scars (HS) remains unclear. This study aimed to explore the role and potential mechanism of autophagy during the development of HS.MethodsRNA and protein expression levels of Beclin-1, p62, and LC3II in normal skin tissues and HS specimens from different patients were examined. Autophagy inducers and inhibitors were used to cure established HS in rabbit ears, and the expression of Beclin-1, p62, and LC3II at the RNA and protein level was determined. Lastly, the effects of autophagy inducers and inhibitors on HS development were analyzed.ResultsCompared to normal skin tissues, the expression of LC3Ⅱ and Beclin-1 was higher (P<0.05), while that of p62 was lower (P<0.05) in HS tissues. In addition, the LC3II/LC3I ratio was increased during HS formation, and the altered expression of the three proteins stabilized after one year. Administration of autophagy inducers enhanced the formation of HS as well as the expression levels of LC3II and Beclin-1 but decreased p62 expression. Meanwhile, administration of autophagy inhibitors increased the expression of LC3II, Beclin-1, and p62, along with reduced HS formation.ConclusionAutophagic activity increased during HS initiation and subsequent stabilization. In addition, autophagy inhibitors were able to inhibit HS formation by suppressing autophagy, whereas autophagy inducers promoted scar hyperplasia by enhancing autophagy.     

High glucose-induced oxidative stress promotes autophagy through mitochondrial damage in rat notochordal cells

Purpose

Diabetes mellitus is associated with an increased risk of intervertebral disc degeneration (IDD). Reactive oxygen species (ROS), oxidative stressors, play a key role in autophagy of diabetes-associated diseases. Mitochondria are known to be the main source of endogenous ROS in most mammalian cell types. The authors therefore conducted the following study to evaluate the effects of high glucose concentrations on the induction of oxidative stress and autophagy through mitochondrial damage in rat notochordal cells.

Methods

Rat notochordal cells were isolated, cultured, and placed in either 10 % fetal bovine serum (normal control) or 10 % fetal bovine serum plus two different high glucose concentrations (0.1 M and 0.2 M) (experimental conditions) for one and three days, respectively. We identified and quantified the mitochondrial damage (mitochondrial transmembrane potential) and the generation of ROS and antioxidants (manganese superoxide dismutase [MnSOD] and catalase). We also investigated expressions and activities of autophagy markers (beclin-1, light chain3-I [LC3-I] and LC3-II, autophagy-related gene [Atg] 3, 5, 7, and 12).

Results

An enhanced disruption of mitochondrial transmembrane potential, which indicates mitochondrial damage, was identified in rat notochordal cells treated with both high glucose concentrations. Both high glucose concentrations increased production of ROS by rat notochordal cells in a dose- and time-dependent manner. The two high glucose solutions also enhanced rat notochordal cells’ compensatory expressions of MnSOD and catalase in a dose- and time-dependent manner. The proautophagic effects of high glucose concentrations were manifested in the form of enhanced rat notochordal cells’ expressions of beclin-1, LC3-II, Atg3, 5, 7, and 12 in a dose- and time-dependent manner. The ratio of LC3-II/LC3-I expression was also increased in a dose- and time-dependent manner.

Conclusions

The findings from this study demonstrate that high glucose-induced oxidative stress promotes autophagy through mitochondrial damage of rat notochordal cells in a dose- and time-dependent manner. These results suggest that preventing the generation of oxidative stress might be a novel therapeutic target by which to prevent or to delay IDD in patients with diabetes mellitus.     

Battling resistance mechanisms in antihormonal prostate cancer treatment: Novel agents and combinations

Prostate cancer (PCa) is a hormone-sensitive disease. Androgen deprivation therapy lowers serum testosterone levels (castration) or blocks the androgen receptor (AR) ligand-binding domain. Especially in metastatic disease, hormonal therapy has been able to delay disease progression, reduce symptoms, and improve overall survival. Despite subsequent disease progression and development of castration resistance, PCa remains AR driven. Secondary hormonal treatments such as abiraterone acetate or enzalutamide have demonstrated increased overall survival. However, new resistance mechanisms to these agents have been identified, and systemic chemotherapy is still needed especially in fast-progressing castration-resistant PCa. Several promising androgen synthesis inhibitors (orteronel and galeterone), AR inhibitors (ARN-509, EPI-001, AZD3514, and ODM-201), and heat shock protein modulators (AT11387, 17-DMAG, STA-9090, and OGX-427) are currently under investigation. The wide variety in upcoming systemic agents underlines the molecular heterogeneity of castration-resistant PCa. This article reviews antihormonal therapy in PCa and resistance mechanisms and focuses on novel and upcoming agents currently in clinical testing.     

Cinnamaldehyde attenuates kidney senescence and injury through PI3K/Akt pathway-mediated autophagy via downregulating miR-155

BackgroundTo prove the internal connection, we deciphered the effect of cinnamaldehyde on kidney senescence through establishing animal and cell models.MethodsIn vivo, a rat senescence model was constructed using D-galactose (D-gal), and the modeled rats were further treated with cinnamaldehyde. In vitro, rat renal tubular epithelial cells (NRK-52E) were transfected with miR-155 mimic or inhibitor and then treated with cinnamaldehyde, D-gal or PI3K inhibitor (LY294002). The serum levels of blood urea nitrogen (BUN) and serum creatinine (Scr) of the rats were measured by an automatic biochemical analyzer. Pathological changes of kidney were determined by hematoxylin-eosin staining. The senescence and viability of NRK-52E cells were assessed by SA-β-gal staining and CCK-8 assay, respectively. The levels of miR-155, p-PI3K/PI3K, p-Akt/Akt, LC3B (LC3-II and LC3-I) and Beclin1 were detected by qRT-PCR, immunohistochemistry, or western blot.ResultsD-gal elevated the levels of BUN, Scr and miR-155 in the kidney, induced the renal pathological damage, inhibited the cell viability, increased the numbers of SA-β-gal-, LC3B- and Beclin1-positive cells and upregulated the levels of LC3-II/LC3-I and Beclin1 both in the kidney and cells. Cinnamaldehyde reversed D-gal-induced effects on the kidney and cells, and moreover, the cinnamaldehyde-induced anti-D-gal effects on cells could be suppressed by miR-155 mimic but promoted by miR-155 inhibitor. LY294002 potentiated D-gal-induced effects, and reversed cinnamaldehyde- and miR-155 inhibitor-caused impacts on the PI3K/Akt pathway and LC3-II/LC3-I level in D-gal-induced cells.ConclusionCinnamaldehyde attenuates kidney senescence and injury through PI3K/Akt pathway-mediated autophagy via downregulating miR-155.     

Cytotoxic effects of delphinidin in human osteosarcoma cells

Introduction

The aim of this study was to evaluate whether delphinidin is cytoprotective or cytotoxic in osteosarcoma cell lines, and to elucidate the underlying mechanisms.

Do antioxidants inhibit oxidative‐stress‐induced autophagy of tenofibroblasts?

Recent research on tendinopathy has focused on its relationship to programmed cell death. Increased autophagy has been observed in ruptured rotator cuff tendon tissues, suggesting a causal relationship. We investigated whether autophagy occurs in human rotator cuff tenofibroblast death induced by oxidative stress and whether antioxidants protect against autophagic cell death. We used H₂O₂ (0.75 mM) as oxidative stressor, cyanidin (100 µg/ml) as antioxidant, zVAD (20 µM) as apoptosis inhibitor, and 3‐MA (10 mM) as autophagy inhibitor. We evaluated cell viability and known autophagic markers: LC3‐II expression, GFP‐LC3 puncta formation, autolysosomes, and Atg5‐12 and Beclin 1 expression. H₂O₂ exposure increased the rates of cell death, LC3‐II expression, GFP‐LC3 puncta formation, and autolysosomes. After we induced apoptosis arrest using zVAD, H₂O₂ exposure still induced cell death, LC3‐II expression, and GFP‐LC3 puncta formation. H₂O₂ exposure also increased Atg5‐12 and Beclin 1 expressions, indicating autophagic cell death. However, cyanidin treatment reduced H₂O₂‐induced cell death, LC3‐II expression, GFP‐LC3 puncta formation, and autolysosomes. Cyanidin and 3‐MA similarly reduced the cell‐death rate, and Atg5‐12 and Beclin 1 expression. This study demonstrated that H₂O₂, an oxidative stressor, induces autophagic cell death in rotator cuff tenofibroblasts, and that cyanidin, a natural antioxidant, inhibits autophagic cell death. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:937–943, 2014.     

Papel de la activación adicional del gen RA en el desarrollo del fenotipo resistente a la castración en el cáncer de próstata

IntroductionSeveral studies have already shown that changes in the AR gene may be associated with a more aggressive disease phenotype and even castration-resistant prostate cancer. Thus, we investigated cytogenetic and molecular alterations linked to AR.Materials and methodsTo evaluate AR methylation, we performed a cytogenetic-molecular analysis using fluorescence in situ hybridization that uses specific probes for the AR gene (Xq11.12) and the X chromosome centromere. For AR activity, we performed a qualitative analysis of human androgen receptor activity. To analyze the expression of AR in PC3 and LNCaP cell lines, we used qPCR assays.ResultsIn the qPCR assay, we found downregulation of AR in the PC3 cell line compared with the LNCaP. We found the presence of X chromosome polysomy in PC-3 and LNCaP cell lines by FISH assay. In the HUMARA-Q assay, we found two X chromosomes/cell and the activity of both AR in the PC-3 cell line. In LNCaP cells, we found two X chromosomes/cell and methylation of only one AR.ConclusionCastration-resistant prostate cancer phenotype represents a significant challenge in the setting of urological management. The X chromosomes and AR-linked alterations may contribute to a better understanding of the disease. However, further studies should be performed in an attempt to elucidate as much as possible the role of AR in the castration-resistant prostate cancer phenotype.     

Los efectos de resveratrol y otros polifenoles del vino sobre la proliferación,apoptosis y expresión de receptor androgénico en células LNCaP

PurposeTo address the effect of resveratrol and other red wine polyphenols on cell proliferation, apoptosis and androgen receptor (AR) expression in human prostate cancer LNCaP cells.Materials and methodsLNCaP cells (5 × 102) were cultured in microtiter plate modules and treated with gallic acid, tannic acid and quercetin (1, 5 and 10 μM), rutin and morin (25, 50 and 75 μM) and resveratrol (5, 10 and 25 μM). To address the extent of proliferation at 24, 48, 72 and 96 hours, a colorimetric immunoassay method was used. An activity caspase 3/7 detection assay was used to disclose apoptosis at 24, 48 and 72 hours. AR mARN levels were determined by real time RT-PCR.ResultsAll polyphenols studied significantly inhibited (P < .05) cell proliferation compared to control. However, there were moderate differences between them. Resveratrol was the strongest inhibitor at different times and doses. Also, caspase-3 and caspase-7 activity was significantly higher (P < .05) than control in the presence of all the compounds, but the earlier response was achieved by resveratrol. Resveratrol, quercetin and morin were the only nutrients that significantly inhibited AR mRNA expression. Again resveratrol produced the highest inhibition (90-250 times less than control), followed by morin (67-100 times) and quercetin (55-91 times).ConclusionsAll polyphenols studied showed important antiproliferative effects and induced apoptosis when added to LNCaP cells culture. We confirm that resveratrol, morin and quercetin may achieve such effect through reduced expression of AR. The synergistic effects of these compounds and their potential to prevent progression of hormone-dependent prostate cancer merit further study.     

Oncogenic activation of androgen receptor

BackgroundThere is considerable evidence implicating the aberrant activation or “reactivation” of androgen receptor in the course of androgen-ablation therapy as a potential cause for the development of castration-resistant prostate cancer. Several non-mutually exclusive mechanisms including the inappropriate activation of androgen receptor (AR) by non-steroids have been postulated. The present work is aimed to understand the role of neuropeptides released by neuroendocrine transdifferentiated prostate cancer cells in the aberrant activation of AR.ObjectivesThe study was designed to study how neuropeptides such as gastrin-releasing peptide activate AR and to define the crucial signal pathways involved, in the hope to identify therapeutic targets.Methods and MaterialsAndrogen-dependent LNCaP cell line was used to study the effects of bombesin/gastrin-releasing peptide on the growth of the cell line and the transactivation of AR. The neuropeptide was either added to the media or introduced as a transgene in LNCaP cells to study its paracrine or autocrine effect on LNCaP growth under androgen-deprived conditions. The activation of AR was monitored by reporter assay, chromatin immunoprecipitation (ChIP) of AR, translocation into the nucleus and cDNA microarray of the AR response genes.ResultsBombesin/gastrin releasing peptides induce androgen-independent growth of LNCaP in vitro and in vivo. It does so by activating AR, which is accompanied by the activation of Src tyrosine kinase and its target c-myc oncogene. The bombesin or Src-activated AR induces an overlapping set of AR response genes as androgen, but they also a unique set of genes. Intriguingly, the Src-activated and androgen-bound ARs differ in their binding specificity toward AR response elements, indicating the receptors activated by these 2 mechanisms are not conformationally identical. Finally, Src inhibitor was shown to effectively block the activation of AR and the growth effects induced by bombesin.ConclusionThe results showed that AR can be activated by neuropeptide, a ligand for G-protein coupled receptor, in the absence of androgen. The activation goes through Src-tyrosine kinase pathway, and tyrosine kinase inhibitor is a potentially useful adjunctive therapy during androgen ablation.     

雄激素剥夺条件下阻断自噬增加LNCaP细胞凋亡

目的 探讨雄激素剥夺条件下阻断自噬后LNCaP细胞凋亡变化与半胱天冬酶(caspase)激活的关系.方法 应用激光共聚焦显微镜、RT-PCR方法观察雄激素剥夺致细胞自噬增加后,利用DAPI染色观察细胞凋亡变化及药物抑制caspase后对凋亡的影响.结果 ①雄激素去除后LNCaP细胞自噬体增加,标准培养基(CM)培养下LNCaP细胞自噬体数量为1.90分;无血清培养基(SF)中细胞自噬体数量增高为2.64分;加入双氧睾酮(SFA组)后细胞自噬体下降至1.85分(P<0.01).CM中LNCaP细胞LC3 mRNA表达率为23%,血清饥饿12 h后,LC3表达量上调至100%,而SFA组LC3 mRNA表达量为86%;血清饥饿24 h后,SF组LC3 mRNA表达量为62%,SFA组为35%.②SF组和SFA组LNCaP细胞基础凋亡率分别为(3.19±1.09)0A和(3.01±0.33)%,加入3-甲基腺嘌呤(3-MA)阻断自噬24 h后,SF组凋亡率为(10.90±2.91)%,SFA组为(4.63±1.69)%.SF+3-MA组中加入Z-VAD-FMK后,细胞凋亡减至(1.16±0.52)%.组间差异有统计学意义(P<0.01).结论 剥夺雄激素后LNCaP细胞中自噬明显增加,阻断自噬后凋亡发生率增加.     

Chimeric molecules facilitate the degradation of androgen receptors and repress the growth of LNCaP cells

Post-translational degradation of protein plays an important role in cell life. We employed chimeric molecules （dihydrotestosterone-based proteolysis-targeting chimeric molecule [DHT-PROTAC]） to facilitate androgen receptor （AR） degradation via the ubiquitin-proteasome pathway （UPP） and to investigate the role of AR in cell proliferation and viability in androgen-sensitive prostate cancer cells. Western blot analysis and immunohistochemistry were applied to analyse AR levels in LNCaP cells after DHT-PROTAC treatment. Cell counting and the 3-（4,5-dimethylthiazol-2-yl）-2,5- diphenyl tetrazolium bromide （MTT） cell viability assay were used to evaluate cell proliferation and viability after AR elimination in both LNCaP and PC-3 cells. AR was tagged for elimination via the UPP by DHT-PROTAC, and this could be blocked by proteasome inhibitors. Degradation of AR depended on DHT-PROTAC concentration, and either DHT or an ALAPYIP-（arg）8 peptide could compete with DHT-PROTAC. Inhibition of cell proliferation and decreased viability were observed in LNCaP cells, but not in PC-3 or 786-0 cells after DHT-PROTAC treatment. These data indicate that AR elimination is facilitated via the UPP by DHT-PROTAC, and that the growth of LNCaP cells is repressed after AR degradation.     

Sevoflurane induces cardioprotection through reactive oxygen species-mediated upregulation of autophagy in isolated guinea pig hearts

Purpose

Sevoflurane increases reactive oxygen species (ROS), which mediate cardioprotection against myocardial ischemia–reperfusion injury. Emerging evidence suggests that autophagy is involved in cardioprotection. We examined whether reactive oxygen species mediate sevoflurane preconditioning through autophagy.

Methods

Isolated guinea pigs hearts were subjected to 30 min ischemia followed by 120 min reperfusion (control). Anesthetic preconditioning was elicited with 2 % sevoflurane for 10 min before ischemia (SEVO). The ROS-scavenger, N-(2-mercaptopropionyl) glycine (MPG, 1 mmol/l), was administered starting 30 min before ischemia to sevoflurane-treated (SEVO + MPG) or non-sevoflurane-treated (MPG) hearts. Infarct size was determined by triphenyltetrazolium chloride stain. Tissue samples were obtained after reperfusion to determine autophagy-related protein (microtubule-associated protein light chain I and II: LC3-I, -II) and 5′ AMP-activated protein kinase (AMPK) expression using Western blot analysis. Electron microscopy was used to detect autophagosomes.

Results

Infarct size was significantly reduced and there were more abundant autophagosomes in SEVO compared with control. Western blot analysis revealed that the ratio of LC3-II/I and phosphorylation of AMPK were significantly increased in SEVO. These effects were abolished by MPG.

Conclusions

Sevoflurane induces cardioprotection through ROS-mediated upregulation of autophagy.     

Autophagy proteins in prostate cancer: Relation with anaerobic metabolism and Gleason score

ObjectivesUp-regulation of autophagy provides an important survival mechanism to normal and malignant cells residing in a hypoxic and unfavorable nutritional environment. Yet, its role in the biology of prostate cancer remains poorly understood.MethodsIn this study we investigated the expression of four major autophagy proteins, namely the microtubule-associated protein 1 light chain 3A (LC3A), LC3B, Beclin 1, and p62, together with an enzyme of anaerobic metabolism, the lactate dehydrogenase 5 (LDH5), in relation to Gleason score and extraprostatic invasion. A series of 96 prostate adenocarcinomas was examined using immunohistochemical techniques and appropriate antibodies.ResultsThe LC3A protein was expressed in the form of “stone-like” structures, and diffuse cytoplasmic staining, the LC3B reactivity was solely cytoplasmic, whereas that of p62 and LDH5 was both cytoplasmic and nuclear. A median count of 0.90 “stone-like” structures per 200×optical field (range 0–3.6) was highly associated with a high Gleason score. Similarly, a strong cytoplasmic LC3A, LC3B, and p62 expression, when extensive (present in>50% tumor cells per section), was significantly associated with LDH5 and a high Gleason score. In addition, extensive cytoplasmic p62 expression was related with LC3A and B reactivity and also with extraprostatic invasion. Extensive Beclin-1 expression was significantly linked with extraprostatic invasion and also with p62 and LDH5 expression.ConclusionsImmunohistochemical detection of autophagy proteins may potentially prove to be useful as prognostic markers and a tool for the stratification of patients in therapeutic trials targeting autophagy in prostate cancer.     

The prostate cancer-up-regulated long noncoding RNA PlncRNA-1 modulates apoptosis and proliferation through reciprocal regulation of androgen receptor

ObjectiveEmerging evidences implicate long noncoding RNAs (lncRNAs) are deregulated in cancer development. The purpose of the current study is to investigate the role of new lncRNA, named PlncRNA-1, in prostate cancer (CaP) pathogenesis.Materials and methodsIn this study, real-time q-PCR was used to demonstrate the expression of PlncRNA-1 in 16 pairs CaP tissues and matched normal tissues, 14 pairs CaP tissues and BPH tissues, 4 CaP cell lines, including LNCaP, LNCaP-AI, PC3, and C4-2, and 2 normal prostate epithelial cell lines RWPE-1 and PWR-1E. After PlncRNA-1 was suppressed by siRNA in LNCaP and LNCaP-AI cell lines, cell proliferation and apoptosis were assessed using CCK-8 and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL). After PlncRNA-1 and AR was suppressed by siRNA in LNCaP and LNCaP-AI cell lines, real-time q-PCR and Western blotting were used to measure reciprocal regulation of PlncRNA-1 and AR.ResultsWe showed that expression PlncRNA-1, was significantly higher in CaP cells relative to normal prostate epithelial cells, as well as higher in human CaPs compared with normal tissues and benign prostatic hyperplasia (BPH). Silencing of PlncRNA-1 significantly reduced cell proliferation and induced apoptosis in CaP cell lines LNCaP and LNCaP-AI. Mechanistically, PlncRNA-1 suppression by siRNA resulted in a decrease of androgen receptor (AR) mRNA, protein and AR downstream target. Of note, blockade of AR signaling with siRNA also resulted in a suppression of PlncRNA-1 expression in CaP cell lines.ConclusionsOur study suggests reciprocal regulation of PlncRNA-1 and androgen receptor contribute to CaP pathogenesis and that PlncRNA-1 is a potential therapy target.     

Vitamin D/vitamin D receptor/Atg16L1 axis maintains podocyte autophagy and survival in diabetic kidney disease

ObjectiveTo investigate the effect of vitamin D/vitamin D receptor (VDR)/Atg16L1 signaling on podocyte autophagy and survival in diabetic nephropathy.MethodsDiabetic rat models were induced by intraperitoneal injection of streptozotocin (STZ) (60 mg/kg) and treated with and without gavage of 0.1 μg/kg/d active vitamin D3 (aVitD3; 1,25- OH vitamin D3) and kidney tissues assessed by histopathology and immunohistochemistry. The murine podocyte cell line MPC-5 was cultured under hyperglycemic conditions in the absence or presence of 100 nmol/L calcitriol to investigate podocyte injury and autophagy. Cell survival rates were analyzed using Cell Counting Kit-8 (CCK-8) assays and the numbers of autophagosomes were determined after transduction with the mRFP-GFP-LC3 autophagy reporter construct. The expression of autophagy-related proteins (LC3-II, beclin-1, Atg16L1) and podocyte-related proteins (nephrin, podocin, synaptopodin, and desmin) was determined by Western blotting.ResultsVDR expression and autophagy were decreased in diabetic nephropathy. Calcitriol treatment repressed renal injury in rat diabetic kidneys and reduced high glucose-induced damage to cultured podocytes. Mechanistically, Atg16L1 was identified as a functional target of VDR, and siRNA-mediated knockdown of VDR and Atg16L1 blocked the protective effects of aVitD3 against podocyte damage.ConclusionAutophagy protects podocytes from damage in DN and is modulated by VitD3/VDR signaling and downstream regulation of Atg16L1 expression.     

Changes in autophagy proteins in a rat model of spinal cord injury

Objective：Autophagy is involved in several neurodegenerative diseases and recently its role in acute brain injury has won increasing interest.Spinal cord injuries （SCIs） often lead to permanent neurological deficit.Therefore,in this study,we examined the profiles of autophagy-linked proteins （MAP-LC3） after SCI to investigate whether the expression of autophagy contributes to neurological deficit after SCI.Methods：Adult female Sprague-Dawley rats were used and randomly divided into control and SCI groups.All the rates received laminectomy at T8-T10 level.Those in the SCI group received additional exposure of the dorsal surface of the spinal cord,followed by a weightdrop injury.Thereafter we investigated the expression levels of MAP-LC3,beclin-1,Cathepsin D and the beclin-1-binding protein bcl-2 by western blot analysis at 12 h,24 h,3 d,7 d,21 d and 28 d.One-way ANOVA with Tukey post hoc test was used to compare data between groups.Results：We observed significant increase in the level of LC3 （LC3-Ⅱ/LC3-Ⅰ） at 3 d and 7 d after SCI when compared with the sham group.While the level of beclin-1 and ratio of beclin-1/bcl-2 was found to have increased from 12 h to 24 h after injury.Cathepsin D expression was also elevated at 7 d （P＜0.01）.Conclusion：Based on the above mentioned data,we proposed that autophagy plays a role in the manifestation of cell injury following SCI.     

Multifaceted effects of rapamycin on functional recovery after spinal cord injury in rats through autophagy promotion,anti-inflammation,and neuroprotection

BackgroundSpinal cord injuries (SCIs) are serious and debilitating health problems that lead to severe and permanent neurological deficits resulting from the primary mechanical impact followed by secondary tissue injury. During the acute stage after an SCI, the expression of autophagy and inflammatory responses contribute to the development of secondary injury. In the present study, we examined the multifaceted effects of rapamycin on outcomes of rats after an SCI.Materials and methodsWe used 72 female Sprague-Dawley rats for this study. In the SCI group, we performed a laminectomy at T10, followed by impact-contusion of the spinal cord. In the control group, we performed only a laminectomy without contusion. We evaluated the effects of rapamycin using the Basso, Beattie, and Bresnahan scale for functional outcomes, Western blot analyses for analyzing LC3-II, tumor necrosis factor expression, and p70S6K phosphorylation, and an immunostaining technique for localization and enumeration of microglial and neuronal cells.ResultsBasso, Beattie, and Bresnahan scores after injury significantly improved in the rapamycin-treated group compared with the vehicle group (on Day 28 after the SCI; P < .05). The Western blot analysis demonstrated that rapamycin enhanced LC3-II expression and decreased p70S6K phosphorylation compared with the vehicle (P < .01), which implies promotion of autophagy through mammalian target of rapamycin inhibition. Furthermore, rapamycin treatment significantly attenuated tumor necrosis factor production and microglial expression (P < .05). Immunohistochemistry of NeuN (antibodies specific to neurons) showed remarkable neuronal cell preservation in the rapamycin-treated group compared with the vehicle-treated group (P < .05), which suggests a neuroprotective effect of rapamycin.ConclusionsRapamycin is a novel neuroprotectant with multifaceted effects on the rat spinal cord after injury. Use of such a clinically established drug could facilitate early clinical trials in selected cases of human SCIs.