Advances on Cell Autophagy and Its Potential Regulatory Factors in Renal Ischemia-Reperfusion Injury

Lrg1 silencing attenuates ischemia-reperfusion renal injury by regulating autophagy and apoptosis through the TGFβ1- Smad1/5 signaling pathway

BACKGROUND

Dysfunction in the processes of autophagy and apoptosis within renal tubular epithelial cells (RTEc) contributes to renal ischemia-reperfusion injury (IRI). However, the factors influencing this dysfunction remain unclear. Leucine-rich alpha-2-glycoprotein 1 (Lrg1) plays a role in the progression of diabetic nephropathy and kidney fibrosis by modulating the activin receptor-like kinase 1 (ALK1)-Smad1/5/8 and TGF-β1/Smad3 pathways, respectively. Therefore, we aimed to investigate whether Lrg1 is involved in the pathological mechanisms of renal IRI and whether its effects are related to the dysregulation of autophagy and apoptosis in RTEc.

METHODS

We conducted in vitro and in vivo experiments using CoCl2-induced hypoxic human kidney-2 (HK-2) cells and mice with renal IRI, respectively. Lrg1 was silenced using siRNA and lentiviral vectors in HK-2 cells and mouse kidneys. Rapamycin (Rapa) and methyladenine were applied to regulate autophagy in renal IRI models.

RESULTS

Increased Lrg1 expression was observed in hypoxic HK-2 cells and in the kidneys of mice with renal IRI. Silencing of Lrg1 through siRNA and lentiviral approaches restored autophagy and suppressed apoptosis in CoCl2-induced hypoxic HK-2 cells and renal IRI models. Additionally, reduced Lrg1 expression alleviated kidney damage caused by renal IRI. The downregulation of Lrg1 expression restrained the TGFβ-Smad1/5 signaling pathway in hypoxic-induced HK-2 cells and renal IRI by reducing ALK1 expression. Lastly, the enhancement of autophagy, achieved through Rapa treatment, provided protection against renal IRI in mice.

CONCLUSIONS

Our findings suggest that Lrg1 silencing can be applied as a potential therapeutic target to inhibit the TGFβ1-Smad1/5 pathway, thereby enhancing autophagy and decreasing apoptosis in patients with acute kidney injury.

The crosslinks between ferroptosis and autophagy in asthma

Autophagy is an evolutionarily conserved cellular process capable of degrading various biological molecules and organelles via the lysosomal pathway. Ferroptosis is a type of oxidative stress-dependent regulated cell death associated with the iron accumulation and lipid peroxidation. The crosslinks between ferroptosis and autophagy have been focused on since the dependence of ferroptosis on autophagy was discovered. Although the research and theories on the relationship between autophagy and ferroptosis remain scattered and fragmented, the crosslinks between these two forms of regulated cell death are closely related to the treatment of various diseases. Thereof, asthma as a chronic inflammatory disease has a tight connection with the occurrence of ferroptosis and autophagy since the crosslinked signal pathways may be the crucial regulators or exactly regulated by cells and secretion in the immune system. In addition, non-immune cells associated with asthma are also closely related to autophagy and ferroptosis. Further studies of cross-linking asthma inflammation with crosslinked signaling pathways may provide us with several key molecules that regulate asthma through specific regulators. The crosslinks between autophagy and ferroptosis provide us with a new perspective to interpret and understand the manifestations of asthma, potential drug discovery targets, and new therapeutic options to effectively intervene in the imbalance caused by abnormal inflammation in asthma. Herein, we introduce the main molecular mechanisms of ferroptosis, autophagy, and asthma, describe the role of crosslinks between ferroptosis and autophagy in asthma based on their common regulatory cells or molecules, and discuss potential drug discovery targets and therapeutic applications in the context of immunomodulatory and symptom alleviation.

An update on the molecular mechanism and pharmacological interventions for Ischemia-reperfusion injury by regulating AMPK/mTOR signaling pathway in autophagy

AMP-activated protein kinase (5'-adenosine monophosphate-activated protein kinase, AMPK)/mammalian target of rapamycin (mTOR) is an important signaling pathway maintaining normal cell function and homeostasis in vivo. The AMPK/mTOR pathway regulates cellular proliferation, autophagy, and apoptosis. Ischemia-reperfusion injury (IRI) is secondary damage that frequently occurs clinically in various disease processes and treatments, and the exacerbated injury during tissue reperfusion increases disease-associated morbidity and mortality. IRI arises from multiple complex pathological mechanisms, among which cell autophagy is a focus of recent research and a new therapeutic target. The activation of AMPK/mTOR signaling in IRI can modulate cellular metabolism and regulate cell proliferation and immune cell differentiation by adjusting gene transcription and protein synthesis. Thus, the AMPK/mTOR signaling pathway has been intensively investigated in studies focused on IRI prevention and treatment. In recent years, AMPK/mTOR pathway-mediated autophagy has been found to play a crucial role in IRI treatment. This article aims to elaborate the action mechanisms of AMPK/mTOR signaling pathway activation in IRI and summarize the progress of AMPK/mTOR-mediated autophagy research in the field of IRI therapy.

Gomisin N attenuated cerebral ischemia-reperfusion injury through inhibition of autophagy by activating the PI3K/AKT/mTOR pathway

BACKGROUND

Ischemic stroke is a major global cause of mortality and permanent disability.  Studies have shown that autophagy is essential to maintain cell homeostasis and inevitably lead to neuronal damage after cerebral ischemia. Gomisin N (GN), lignin isolated from Schisandra chinensis, possesses multiple pharmacological activities. However, there is no research on the potential of GN for neuroprotection in ischemic stroke.

PURPOSE

The current work aimed to explore the potential therapeutic possibilities of GN on ischemic stroke and investigate the underlying molecular mechanisms.

STUDY DESIGN

The neuroprotective effects of GN on PC12 cells induced by oxygen glucose deprivation/reoxygenation (OGD/R) and mice with middle cerebral artery occlusion/reperfusion (MCAO/R) injury were investigated.

METHODS

On day 3 after ischemia, the infarct volume and neurological function were assessed. The level of autophagy was measured in vivo and in vitro using Transmission electron microscopy (TEM) and Monodansylcadaverine (MDC) staining. The interaction between GN and PI3K/AKT/mTOR pathway was investigated by molecular docking. Additionally, the expressions of critical proteins in the PI3K/AKT/mTOR signaling pathway and autophagy markers were determined by western blotting.

RESULTS

In compared to the Model group, GN might considerably improve the neurological and locomotor function following a stroke, as well as lower the volume of the cerebral infarct volume and the number of autophagosomes. GN therapy may suppress autophagy by activating the PI3K/Akt/mTOR signaling pathway in the penumbra. In vitro, MDC and TEM results showed that GN treatment obviously suppressed autophagy. Meanwhile, GN downregulated LC3II/LC3I expression ratio while upregulated the p62 expression level. In further studies, GN dramatically boosted the expression ratios of p-PI3K/PI3K, p-AKT/AKT, and p-mTOR/mTOR proteins in PC12 cells following OGD/R damage. However, the PI3K inhibitor (LY294002) reversed the increase of p-PI3K/PI3K, p-AKT/AKT, and p-mTOR/mTOR expression ratio induced by GN administration. Also, LY294002 significantly partially attenuated GN induced reduction of autophagy and increase of cell viability compared with GN treatment alone.

CONCLUSIONS

Here, we first demonstrate the neuroprotective effects of GN on MCAO mice and OGD/R induced PC12 cells injury. A possible mechanism by which GN prevents ischemic stroke is proposed: GN could restrain autophagy by stimulating the PI3K/AKT/mTOR signaling pathways. More effects and mechanisms of GN on the rehabilitation of ischemic stroke are worthy to be explored in the future.

miR-211-5p Alleviates the Myocardial Ischemia Injury Induced by Ischemic Reperfusion Treatment via Targeting FBXW7

Cardiovascular diseases, a class of the most common diseases, seriously threaten human health, which is a direct inducement of death in most countries. The restoration of blood supply is an impactful intervention way for cardiovascular disease treatments while the injury induced by oxygen-glucose deprivation and ischemic reperfusion (I/R) may further impact the tissues of the patients. Myocardial reperfusion is a precondition for saving ischemic myocardial tissues in acute myocardial infarction while the injury induced by immediate reperfusion takes a great challenge for cardiovascular disease treatment. Howbeit, the reperfusion of coronary blood could aggravate the injury triggered by ischemia. At present, several studies have focused on the etiopathogenesis and therapeutic strategies of ischemia-reperfusion injury of the myocardium. The report has verified that miR-211-5p was elevated in the pathological specimens, while the influence of miR-211-5p in I/R-mediated injury of myocardial cells remains unclear. This research is aimed at illustrating the role of miR-211-5p in the progression of I/R injury of myocardial cells, and qRT-PCR, western blot, CCK-8, and TUNEL assay were used to investigate the functions of miR-211-5p on I/R-mediated injury of myocardial cells. The result mirrored that miR-211-5p was distinctly reduced in the I/R-induced AC16, and reduced miR-211-5p could evidently improve the viability of I/R-induced AC16. miR-211-5p could directly target FBXW7, and FBXW7 upregulation could reverse the improvement of AC16 in viability and apoptosis level after suffering I/R. Moreover, it was also proved that miR-211-5p can mediate the activation of Wnt/β-catenin via attenuating FBXW7. Consequently, this investigation identified miR-211-5p as a positive role to attenuate the injury of myocardial cells when suffering I/R treatment.

Role of tRNA derived fragments in renal ischemia-reperfusion injury

Background

Ischemia–reperfusion injury (IRI) is one of the major causes of acute kidney injury (AKI). tRNA derived fragments (tRFs/tiRNAs) are groups of small noncoding RNAs derived from tRNAs. To date, the role of tRFs/tiRNAs in renal IRI has not been reported. Herein, we aimed to investigate the involvement of tRFs/tiRNAs in the occurrence and development of ischemia–reperfusion-induced AKI.

Methods

Moderate/severe renal IRI mouse models were established by bilateral renal pedicle clamping. The tRF/tiRNA profiles of healthy controls and moderate/severe IRI-stressed kidney tissues were sequenced by Illumina NextSeq 500. Candidate differentially expressed tiRNAs were further verified by RT-qPCR. Biological analysis was also performed.

Results

Overall, 152 tRFs/tiRNAs were differentially expressed in the moderate ischemic injury group compared with the normal control group (FC > 2, p < 0.05), of which 47 were upregulated and 105 were downregulated; in the severe ischemic injury group, 285 tRFs/tiRNAs were differentially expressed (FC > 2, p < 0.05), of which 157 were upregulated, and 128 were downregulated. RT-qPCR determination of eight abundantly expressed tiRNAs was consistent with the sequencing results. Gene Ontology analysis for target genes of the tRFs/tiRNAs showed that the most enriched cell components, molecular functions and biological processes were Golgi apparatus, cytoplasmic vesicles, protein binding, cellular protein localization and multicellular organism development. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that these target genes were mainly involved in the natural killer cell mediated cytotoxicity pathway, citrate cycle, and regulation of actin cytoskeleton signaling pathway.

Conclusion

Our results indicated that tRFs/tiRNAs were involved in renal IRI. These tRFs/tiRNAs may be effective partly via regulation of renal immunity, inflammation and metabolism processes. Candidate genes, including tiRNA-Gly-GCC-003, tiRNA-Lys-CTT-003, and tiRNA-His-GTG-002, might be potential biomarkers and therapeutic targets of ischemia–reperfusion injury-induced acute kidney injury.

Ischemic Preconditioning Alleviates Mouse Renal Ischemia/Reperfusion Injury by Enhancing Autophagy Activity of Proximal Tubular Cells

OBJECTIVES

Ischemia/reperfusion injury (IRI) is one of the most vital pathogenesis leading to kidney injury but lacks effective prevention and treatment strategies. This study was conducted to investigate the influences of ischemic preconditioning (IPC) on the pathological process of mouse renal IRI (RIRI) and to figure out the role of autophagy of proximal tubular cells (PTCs) in this process.

METHODS

C57BL/6J mice were randomized to three groups, i.e., sham-operated group, ischemia/reperfusion (I/R) group, and IPC + I/R group. Meanwhile, 3-methyladenine, an autophagy inhibitor, was administered when further verification was needed. Histological and functional severity of kidney injury, the autophagy and apoptosis activity of PTCs, as well as the characterization of the immune cell infiltration landscape in kidney tissues were investigated. Furthermore, HK-2 cells and primary cultured PTC were cultured to set up the hypoxic preconditioning and hypoxia/reoxygenation model for in vitro simulation and verification, and a microarray dataset derived from the Gene Expression Omnibus database was analyzed to explore the transcriptome profiles after IPC.

RESULTS

IPC could significantly attenuate I/R-induced kidney injury functionally and histologically both in the acute and recovery phase of RIRI by enhancing the autophagy activity of PTCs. Cell autophagy could regulate the release of monocyte chemoattractant protein-1, and sequentially decrease macrophages infiltration in kidney tissues in the acute phase of RIRI, thus mediating the reno-protective effect.

CONCLUSIONS

IPC could attenuate mouse RIRI-induced kidney injury. IPC-mediated activation of autophagy of PTCs plays a vital role in affording protection in RIRI-induced kidney injury.

Ebselen ameliorates renal ischemia-reperfusion injury via enhancing autophagy in rats

Renal ischemia-reperfusion (I/R) injury is one of the most common causes of chronic kidney disease (CKD). It brings unfavorable outcomes to the patients and leads to a considerable socioeconomic burden. The study of renal I/R injury is still one of the hot topics in the medical field. Ebselen is an organic selenide that attenuates I/R injury in various organs. However, its effect and related mechanism underlying renal I/R injury remains unclear. In this study, we established a rat model of renal I/R injury to study the preventive effect of ebselen on renal I/R injury and further explore the potential mechanism of its action. We found that ebselen pretreatment reduced renal dysfunction and tissue damage caused by renal I/R. In addition, ebselen enhanced autophagy and inhibited oxidative stress. Additionally, ebselen pretreatment activated the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway. The protective effect of ebselen was suppressed by autophagy inhibitor wortmannin. In conclusion, ebselen could ameliorate renal I/R injury, probably by enhancing autophagy, activating the Nrf2 signaling pathway, and reducing oxidative stress.

Fingolimod attenuates renal ischemia/reperfusion-induced acute lung injury by inhibiting inflammation and apoptosis and modulating S1P metabolism

Objective

This study examined whether the immunomodulator fingolimod (FTY720) could alleviate renal ischemia/reperfusion (I/R)-induced lung injury and explored the potential mechanisms.

Methods

Renal I/R was established in a rat model, and FTY720 (0.5, 1, or 2 mg/kg) was injected intraperitoneally after 15 minutes of ischemia. Pro-inflammatory cytokine levels, oxidative stress, apoptosis, and the mRNA expression of the sphingosine-1-phosphate (S1P)-related signaling pathway genes sphingosine kinase-1 (SphK1) and sphingosine kinase-2 were analyzed in lung tissue.

Results

Increased pro-inflammatory cytokine levels; decreased total superoxide dismutase, catalase, and glutathione peroxidase levels; increased apoptosis; and increased S1P lyase and SphK1 expression were observed following renal I/R. FTY720 reversed renal I/R-induced changes and effectively attenuated lung injury.

Conclusion

FTY720 protected against acute lung injury in rats subjected to renal I/R by decreasing pulmonary inflammation and apoptosis, increasing oxidative stress, and modulating S1P metabolism.

miRNA-182/Deptor/mTOR axis regulates autophagy to reduce intestinal ischaemia/reperfusion injury

It had been reported miR‐182 was down‐regulated after intestinal ischaemia/reperfusion (I/R) damage. However, its role and potential mechanisms are still unknown. This study was aimed to elucidate the function of miR‐182 in intestinal I/R injury and the underlying mechanisms. The model of intestinal injury was constructed in wild‐type and Deptor knockout (KO) mice. Haematoxylin‐eosin staining, Chiu's score and diamine oxidase were utilized to detect intestinal damage. RT‐qPCR assay was used to detected miR‐182 expression. Electronic microscopy was used to detect autophagosome. Western blot was applied to detect the expression of Deptor, S6/pS6, LC3‐II/LC3‐I and p62. Dual‐luciferase reporter assay was used to verify the relationship between miR‐182 and Deptor. The results showed miR‐182 was down‐regulated following intestinal I/R. Up‐regulation of miR‐182 reduced intestinal damage, autophagy, Deptor expression and enhanced mTOR activity following intestinal I/R. Moreover, suppression of autophagy reduced intestinal damage and inhibition of mTOR by rapamycin aggravated intestinal damage following intestinal I/R. Besides, damage of intestine was reduced and mTOR activity was enhanced in Deptor KO mice. In addition, Deptor was the target gene of miR‐182 and was indispensable for the protection of miR‐182 on intestine under I/R condition. Together, our research implicated up‐regulation of miR‐182 inhibited autophagy to alleviate intestinal I/R injury via mTOR by targeting Deptor.

Huoxue-Tongluo-Lishui-Decoction is visual-protective against retinal ischemia-reperfusion injury

Retinal ischemia reperfusion injury (IRI) is a leading cause of visual impairment or blindness, and an effective way to prevent the visual loss needs to be developed. Although decades of clinical application of Huoxue-Tongluo-Lishui-Decoction (HTLD) has demonstrated its reliable clinical efficacy against retinal IRI, no convincing randomized controlled trials were conducted in humans or animals, and the associated mechanism still needs to be explored. To confirm the protective effect of HTLD against retinal IRI and to explore its underlying mechanisms, a standard retinal IRI animal model, randomized controlled trials, objective evaluation and examination methods were adopted in this study. Flash visual evoked potentials (F-VEP) was performed 8 weeks post-reperfusion. The results showed that the medium dose of HTLD had better treatment effects than low dose of HTLD. High dose of HTLD did not further improve visual function relative to medium dose of HTLD, but had poor performance in the latency of P2 wave. The angio-optical coherence tomography (angio-OCT) examination showed that retinal nerve fiber layer (RNFL) became edematous in the early stage, then the edema subsided, and RNFL became thinning in the late stage. HTLD reduced the swelling of RNFL in the early stage and prevented the thinning of RNFL in the late stage. Similar to F-VEP, medium dose of HTLD has the best neural-protective effects against retinal IRI. In mechanisms, HTLD treatment not only enhanced autophagy at 6 h after reperfusion, but extended the enhancing effect until at least 24 h. HTLD treatment significantly reduced the cleaved Caspase-3, cleaved PARP and Caspase-3 activity at 48 h after reperfusion. HTLD inhibited neuro-toxic cytokines expression in retinal IRI by modulating Akt/NF-kB signaling. HTLD treatment enhanced the expressions of L-glutamate/L-aspartate transporter (GLAST) and glutamine synthetase (GS), and lower the concentration of free glutamate in retina after reperfusion. The phosphorylation of iNOS increased significantly in retinal IRI at 6 h, and HTLD treatment suppressed the phosphorylation of Inducible nitric oxide synthetase (iNOS). In conclusion, HTLD is visual-protective against retinal IRI, and the regulation of autophagy, apoptosis and neuro-toxic mediators may be the underlying mechanisms. These findings may provide new ideas for the clinical treatment of retinal IRI related diseases.

Inhibition of excessive mitophagy by N-acetyl-L-tryptophan confers hepatoprotection against Ischemia-Reperfusion injury in rats

In order to investigate the mechnism of hepatoprotective of N-acetyl-L-tryptophan (L-NAT) against ischemia-reperfusion (I/R) injury, the effects of L-NAT were investigated in hepatic ischemia-reperfusion injury (HIRI) models both in vitro and in vivo, which were made by BRL cells and Sprague-Dawley (SD) rats, respectively. The cell viability of hepatocyte was assessed by cell counting kit-8 (CCK-8) staining. The activation of autophagy was detected by electron microscopy (EM), quantitative real-time PCR (qRT-PCR), Western blotting and immunofluorescence. The activation of mitophagy was determined by the change of autophagy related protein, change of mitochondrial structure and function, co-location of autophagy protein and MitoTracker. Results showed that the morphological structures of hepatocytes were changed significantly after HIRI, and the cell viability of hydrogen peroxide (H₂O₂)-induced BRL cells was decreased. Autophagy markers Beclin1, microtubule associated protein 1 light chain 3-II (LC3-II) and autophagy related protein-7 (ATG-7) were highly expressed and the expression of SQSTM1 (P62) was decreased after HIRI, which suggested that autophagy of hepatocytes was activated after I/R. The reduction of ATP, mitochondrial DNA (mtDNA) and the mitochondrial transmembrane potential (ΔΨm) after H₂O₂-induced revealed that function of mitochondrial had also undergone significant changes. The increased expression of autophagy protein, destructure of mitochondria and mitochondrial dysfunction, the increased co-location of Beclin1 and MitoTracker induced by H₂O₂ implied the excessive mitophagy. The expression of the autophagy protein was increased by 3-Methyladenine (3-MA), providing another piece of evidence. Importantly, all changes were restored by L-NAT pretreament. In conclusion, the present findings demonstrate that excessive mitophagy involved in the process of HIRI and L-NAT may protect hepatocytes against HIRI by inhibiting activation of mitophagy and improving the structure and function of mitochondria.

Propofol post-conditioning lessens renal ischemia/reperfusion-induced acute lung injury associated with autophagy and apoptosis through MAPK signals in rats

Renal Ischemia/Reperfusion (rI/R)-induced acute lung injury (ALI) is a major problem in rI/R. The objective of the current study was to explore the defensive roles of propofol (Pro), an intravenous anesthetic, on rI/R-induced ALI through mitogen-activated protein kinase (MAPK) signaling. Rats were divided into Sham, Pro (10 mg/kg), rI/R, rI/R + Pro (5 mg/kg), and rI/R + Pro (10 mg/kg) groups. Rats were treated with Pro at 1 h after rI/R treatment. Serum and lung tissues at 24 h after rI/R were collected to evaluate morphological changes and the expression of myeloperoxidase (MPO), inflammatory cytokines, and crucial proteins in the MAPK pathway. Pro attenuated the production of mediators, resulting in reduced levels of autophagy and apoptosis by restricting the MAPK pathway in rI/R-induced ALI model. Pro represses rI/R-induced pulmonary autophagy and apoptosis by decreasing the production of inflammatory molecules, and the effects of Pro are involved in the inhibition of the MAPK pathway.

Eugenol Attenuates Cerebral Ischemia-Reperfusion Injury by Enhancing Autophagy via AMPK-mTOR-P70S6K Pathway

Eugenol, as an active compound isolated from Acorus gramineus, has been shown to protect against cerebral ischemia-reperfusion (I/R) injury. Nonetheless, the detailed neuroprotective mechanisms of eugenol in cerebral I/R injury have not been elaborated. In the present study, cerebral I/R injury model was established by middle cerebral artery occlusion (MCAO) in rats. HT22 cells were subjected to oxygen-glucose deprivation/reperfusion (OGD/R) to mimic cerebral I/R injury in vitro. The results showed that eugenol pre-treatment relieved cerebral I/R injury as evidenced by improving neurological deficits and reducing infarct volume. Autophagy was induced by MCAO, which was further promoted by eugenol administration. Moreover, rapamycin, an activator of autophagy, promoted eugenol-induced decreases in neurological score, infarct volume, brain water content, and apoptosis. However, pretreatment with 3-MA, an inhibitor of autophagy, led to the opposite results. Similarly, eugenol pretreatment increased the viability and restrained apoptosis of OGD/R-challenged HT22 cells. OGD/R-induced autophagy was strengthened by eugenol. Mechanically, eugenol promoted autophagy through regulating AMPK/mTOR/P70S6K signaling pathway in vivo and in vitro. In conclusion, pretreatment with eugenol attenuated cerebral I/R injury by inducing autophagy via AMPK/mTOR/P70S6K signaling pathway.

Trehalose attenuates renal ischemia-reperfusion injury by enhancing autophagy and inhibiting oxidative stress and inflammation

Renal ischemia-reperfusion (IR) injury is one of the most common acute kidney injuries, but there is still a lack of effective treatment in the clinical setting. Trehalose (Tre), a natural disaccharide, has been demonstrated to protect against oxidative stress, inflammation, and apoptosis. However, whether it could protect against IR-induced renal injury needs to be investigated. In an in vivo experiment, C57BL/6J mice were pretreated with or without Tre (2 g/kg) through a daily single intraperitoneal injection from 3 days before renal IR surgery. Renal function, apoptosis, oxidative stress, and inflammation were analyzed to evaluate kidney injury. In an in vitro experiment, mouse proximal tubular cells were treated with or without Tre under a hypoxia/reoxygenation condition. Western blot analysis, autophagy flux detection, and apoptosis assay were performed to evaluate the level of autophagy and antiapoptotic effect of Tre. The in vivo results showed that the renal damage induced by IR was ameliorated by Tre treatment, as renal histology and renal function were improved and the enhanced protein levels of kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin were blocked. Moreover, autophagy was activated by Tre pretreatment along with inhibition of the IR injury-induced apoptosis, oxidative stress, and inflammation. The in vitro results showed that Tre treatment activated autophagy and protected against hypoxia/reoxygenation-induced tubular cell apoptosis and oxidative stress. Our results demonstrated that Tre protects against IR-induced renal injury, possibly by enhancing autophagy and blocking oxidative stress, inflammation, and apoptosis, suggesting its potential use for the clinical treatment of renal IR injury.

A Review of ULK1-Mediated Autophagy in Drug Resistance of Cancer

The difficulty of early diagnosis and the development of drug resistance are two major barriers to the successful treatment of cancer. Autophagy plays a crucial role in several cellular functions, and its dysregulation is associated with both tumorigenesis and drug resistance. Unc-51-like kinase 1 (ULK1) is a serine/threonine kinase that participates in the initiation of autophagy. Many studies have indicated that compounds that directly or indirectly target ULK1 could be used for tumor therapy. However, reports of the therapeutic effects of these compounds have come to conflicting conclusions. In this work, we reviewed recent studies related to the effects of ULK1 on the regulation of autophagy and the development of drug resistance in cancers, with the aim of clarifying the mechanistic underpinnings of this therapeutic target.