Pharmacological inhibition of autophagy by 3-MA attenuates hyperuricemic nephropathy

Elucidating the substance basis and pharmacological mechanism of Fufang Qiling granules in modulating xanthine oxidase for intervention in hyperuricemia

ETHNOPHARMACOLOGICAL RELEVANCE

Fufang Qiling granules (FQG), derived from the traditional Qiling Decoction with a longstanding clinical history, is utilized for the treatment of hyperuricemia (HUA). FQG is formulated with a combination of seven Chinese herbs based on the principles of traditional Chinese medicine (TCM) theories. Clinical evidence indicates that FQG exhibits favorable therapeutic effects in reducing uric acid (UA) levels and attenuating renal damage.

AIM OF THIS STUDY

To elucidate the potential active components and pharmacological mechanism of FQG in the treatment of HUA, and to provide an experimental basis for the development of efficient and low-toxicity TCM for HUA treatment.

MATERIALS AND METHODS

A HUA rat model induced by potassium oxonate and adenine was established to initially evaluate the hypouricemic effects of FQG. Chemical analyses were conducted using an ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). Network pharmacology was used to investigate the active components and mechanism of FQG in the treatment of HUA. Potential Xanthine oxidase (XOD) inhibitors were screened from FQG based on ultrafiltration liquid chromatography and mass spectrometry (UF-LC-MS). Molecular docking, surface plasmon resonance (SPR) and circular dichroism (CD) spectroscopy were applied to validate the interactions between the active components and XOD.

RESULTS

In comparison to the model group, treatment with FQG significantly decreased serum UA, serum creatinine (CREA), serum blood urea nitrogen (BUN), and liver XOD activity. Additionally, the FQG administration notably ameliorated HUA-induced renal injury in rats. Through the pharmacodynamics of the HUA rat models and network pharmacology, it was found that XOD was a key pathway enzyme in UA metabolism. 18 XOD inhibitors were screened from FQG by UF-LC-MS, and 11 compounds with strong affinity were verified by SPR, molecular docking and CD spectroscopy.

CONCLUSION

In summary, flavonoids, organic acids and saponins may be the active components in FQG that alleviate HUA. The primary mechanism of FQG involves inhibiting XOD enzyme activity in the plasma to reduce UA production, alleviating renal tubular epithelial cell necrosis, tubulointerstitial injury, fibrosis, and urate deposition, ultimately exerting a therapeutic effect on HUA.

Resveratrol activates autophagy and protects from UVA-induced photoaging in human skin fibroblasts and the skin of male mice by regulating the AMPK pathway

Skin photoaging is mostly caused by ultraviolet A (UVA), although active medications to effectively counteract UVA-induced photoaging have not yet been created. Resveratrol, a naturally occurring polyphenol found in the skin of grapes, has been shown to have various biological functions such as anti-inflammatory and antioxidant characteristics. However, the role of resveratrol in UVA-induced photoaging has not been clarified. We investigated the mechanism of action of resveratrol by UVA irradiation of human skin fibroblasts (HSF) and innovatively modified a mouse model of photoaging. The results demonstrated that resveratrol promoted AMP-activated protein kinase (AMPK) phosphorylation to activate autophagy, reduce reactive oxygen species (ROS) production, inhibit apoptosis, and restore normal cell cycle to alleviate UVA-induced photoaging. In addition, subcutaneous injection of resveratrol not only improved the symptoms of roughness, erythema, and increased wrinkles in the skin of UVA photodamaged mice, but also alleviated epidermal hyperkeratosis and hyperpigmentation, reduced inflammatory responses, and inhibited collagen fiber degradation. In conclusion, our studies proved that resveratrol can treat UVA-induced photoaging and elucidated the possible molecular mechanisms involved, providing a new therapeutic strategy for future anti-aging.

Xanthoceras sorbifolium leaves alleviate hyperuricemic nephropathy by inhibiting the PI3K/AKT signaling pathway to regulate uric acid transport

ETHNOPHARMACOLOGICAL RELEVANCE

In China, Xanthoceras sorbifolium Bunge was first documented as "Wen Guan Hua" in the "Jiu Huang Ben Cao" in 1406 A.D. According to the "National Compilation of Chinese Herbal Medicine," X. sorbifolium leaves are sweet and flat in nature and can dispel wind and dampness, suggesting that their extract can be used to treat rheumatoid arthritis. X. sorbifolium Bunge has also been used to treat arteriosclerosis, hyperlipidemia, hypertension, chronic hepatitis, and rheumatism, complications associated with hyperuricemic nephropathy (HN), a condition characterized by kidney damage resulting from high levels of uric acid (UA) in the blood.

AIM OF THE STUDY

The purpose of this study was to investigate the effects and underlying mechanisms of a 70% ethanol extract from X. sorbifolium leaves (EX) in alleviating HN.

MATERIALS AND METHODS

A mouse model of hyperuricemia was established to initially evaluate the hypouricemic effects and determine the effective dose of EX. Phytochemical analyses were conducted using ultra high-performance liquid chromatography and liquid chromatography-mass spectroscopy. The potential key pathways of EX in the alleviation of HN were inferred using network pharmacology and bioinformatics. An HN rat model was then established, and experiments including biomarker detection, western blotting, reverse transcription quantitative polymerase chain reaction, immunohistochemical and Masson's trichrome staining, and transmission electron microscopy were conducted to evaluate the effect of EX on UA transporter expression in vitro.

RESULTS

Network pharmacology and bioinformatics analyses revealed that the phosphoinositide 3-kinase (PI3K)/AKT signaling pathway was the key pathway for the alleviation of HN progression by EX. EX treatment reduced serum biomarkers in HN rats, downregulated the expression of p-PI3K, p-AKT, glucose transporter 9 (GLUT9), urate transporter 1 (URAT1), Collagen I, matrix metalloproteinase (MMP)-2, and MMP-9, and upregulated the expression of ATP binding cassette subfamily G member 2 (ABCG2) to improve renal interstitial fibrosis in HN rats. A high content of both quercitrin and cynaroside were identified in EX; their administration inhibited the increased expression of GLUT9 and URAT1 in damaged HK-2 cells.

CONCLUSION

Our study provides evidence that EX alleviates HN. The potential mechanism underlying this effect may be the regulation of UA transporters, such as GLUT9 and URAT1, by limiting the activation of the PI3K/AKT signaling pathway to improve renal injury.

Unveiling Selected Influences on Chronic Kidney Disease Development and Progression

Currently, more and more people are suffering from chronic kidney disease (CKD). It is estimated that CKD affects over 10% of the population worldwide. This is a significant issue, as the kidneys largely contribute to maintaining homeostasis by, among other things, regulating blood pressure, the pH of blood, and the water-electrolyte balance and by eliminating unnecessary metabolic waste products from blood. What is more, this disease does not show any specific symptoms at the beginning. The development of CKD is predisposed by certain conditions, such as diabetes mellitus or hypertension. However, these disorders are not the only factors promoting the onset and progression of CKD. The primary purpose of this review is to examine renin-angiotensin-aldosterone system (RAAS) activity, transforming growth factor-β1 (TGF-β1), vascular calcification (VC), uremic toxins, and hypertension in the context of their impact on the occurrence and the course of CKD. We firmly believe that a deeper comprehension of the cellular and molecular mechanisms underlying CKD can lead to an enhanced understanding of the disease. In the future, this may result in the development of medications targeting specific mechanisms involved in the decline of kidney function. Our paper unveils the selected processes responsible for the deterioration of renal filtration abilities.

Aminoguanidine alleviates gout in goslings experimentally infected with goose astrovirus-2 by reducing kidney lesions

Goose astrovirus (GAstV)-2, a novel pathogen identified in 2018, mainly causes visceral gout in goslings, leading to approximately 50% mortality. At present, no commercial veterinary products are available to prevent and treat the disease. Our previous studies showed that nitric oxide (NO) and inducible NO synthase (iNOS) were markedly higher in the kidney and spleen of goslings infected with GAstV-2, but their effects during GAstV-2 infection remain unclear. In the present study, goslings were intraperitoneally injected with aminoguanidine (AG)-an iNOS inhibitor-to examine the role of NO during GAstV-2 infection. AG significantly decreased the serum NO concentration and iNOS mRNA expression in the kidney. Moreover, AG reduced the mortality, serum uric acid and creatinine content, and urate deposition in visceral organs and joints. Histopathological analysis demonstrated that AG reduced renal tubular cell necrosis, inflammatory cell infiltration, glycogen deposition in glomerular mesangium, and interstitial fibrosis, suggesting alleviation of kidney lesions. Furthermore, AG decreased the expression of renal injury markers such as KIM-1 and desmin; inflammatory cytokine-related genes such as IL-1β, IL-8, and MMP-9; and autophagy-related genes and proteins such as LC3II, ATG5, and Beclin1. However, quantitative real-time PCR and immunohistochemistry showed that treatment with AG did not affect the kidney and liver viral load. These findings suggest that AG decreases the mortality rate and kidney lesions in goslings infected with GAstV-2 through mechanisms associated with autophagy and inhibition of inflammatory cytokine production in the kidney but not with GAstV-2 replication.

Bi Xie Fen Qing Yin decoction alleviates potassium oxonate and adenine induced-hyperuricemic nephropathy in mice by modulating gut microbiota and intestinal metabolites

This study aimed to evaluate the preventive effect of Bi Xie Fen Qing Yin (BXFQY) decoction on hyperuricemic nephropathy (HN). Using an HN mouse model induced by oral gavage of potassium oxonate and adenine, we found that BXFQY significantly reduced plasma uric acid levels and improved renal function. Further study shows that BXFQY suppressed the activation of the NLRP3 inflammasome and decreased the mRNA expressions of pro-inflammatory and fibrosis-associated factors in renal tissues of HN mice. Also, BXFQY prevented the damage to intestinal tissues of HN mice, indicative of suppressed colonic inflammation and increased gut barrier integrity. By 16 S rDNA sequencing, BXFQY significantly improved gut microbiota dysbiosis of HN mice. On the one hand, BXFQY down-regulated the abundance of some harmful bacteria, like Desulfovibrionaceae, Enterobacter, Helicobacter, and Desulfovibrio. On the other hand, BXFQY up-regulated the contents of several beneficial microbes, such as Ruminococcaceae, Clostridium sensu stricto 1, and Streptococcus. Using gas or liquid chromatography-mass spectrometry (GC/LC-MS) analysis, BXFQY reversed the changes in intestinal bacterial metabolites of HN mice, including indole and BAs. The depletion of intestinal flora from HN or HN plus BXFQY mice confirmed the significance of gut microbiota in BXFQY-initiated treatment of HN. In conclusion, BXFQY can alleviate renal inflammation and fibrosis of HN mice by modulating gut microbiota and intestinal metabolites. This study provides new insight into the underlying mechanism of BXFQY against HN.

The Function of Autophagy in the Initiation, and Development of Breast Cancer

Autophagy is a significant catabolic procedure that increases in stressful conditions. This mechanism is mostly triggered after damage to the organelles, the presence of unnatural proteins, and nutrient recycling in reaction to these stresses. One of the key points in this article is that cleaning and preserving damaged organelles and accumulated molecules through autophagy in normal cells helps prevent cancer. Since dysfunction of autophagy is associated with various diseases, including cancer, it has a dual function in tumor suppression and expansion. It has newly become clear that the regulation of autophagy can be used for the treatment of breast cancer, which has a promising effect of increasing the efficiency of anticancer treatment in a tissue- and cell-type-specific manner by affecting the fundamental molecular mechanisms. Regulation of autophagy and its function in tumorigenesis is a vital part of modern anticancer techniques. This study discusses the current advances related to the mechanisms that describe essential modulators of autophagy involved in the metastasis of cancers and the development of new breast cancer treatments.

PDGFβ receptor-targeted delivery of truncated transforming growth factor β receptor type II for improving the in vitro and in vivo anti-renal fibrosis activity via strong inactivation of TGF-β1/Smad signaling pathway

Truncated transforming growth factor β receptor type II (tTβRII), serving as a trap for binding excessive transforming growth factor β1 (TGF-β1) by means of competing with wild-type TβRII, is a promising strategy for the treatment of kidney fibrosis. Platelet-derived growth factor β receptor (PDGFβR) is highly expressed in interstitial myofibroblasts in kidney fibrosis. This study identified the interaction between a novel tTβRII variant Z-tTβRII (PDGFβR-specific affibody ZPDGFβR fused to the N-terminus of tTβRII) and TGF-β1. Moreover, Z-tTβRII highly targeted to TGF-β1-activated NIH3T3 cells and UUO-induced fibrotic kidney, but less to normal cells, tissues, and organs. Furthermore, Z-tTβRII significantly inhibited cell proliferation and migration, and reduced fibrosis markers expression and phosphorylation level of Smad2/3 in activated NIH3T3 cells. Meanwhile, Z-tTβRII markedly alleviated the kidney histopathology and fibrotic responses, and inhibited the TGF-β1/Smad signaling pathway in UUO mice. Besides, Z-tTβRII showed good safety performance in the treatment of UUO mice. In conclusion, these results demonstrated that Z-tTβRII may be a potential candidate for a targeting therapy on renal fibrosis due to the high potential of fibrotic kidney-targeting and strong anti-renal fibrosis activity.

Autophagy inhibitor 3-methyladenine attenuates renal injury in streptozotocin-induced diabetic mice

Objectives

To investigate whether 3-methyladenine (3-MA) can protect the kidney of streptozotocin (STZ) - induced diabetes mice, and explore its possible mechanism.

Materials and Methods

STZ was used to induce diabetes in C57BL/6J mice. The mice were divided into normal control group (NC), diabetes group (DM), and diabetes+3-MA intervention group (DM+3-MA). Blood glucose, water consumption, and body weight were recorded weekly. At the end of the 6th week of drug treatment, 24-hour urine was collected. Blood and kidneys were collected for PAS staining to evaluate the degree of renal injury. Sirius red staining was used to assess collagen deposition. Blood urea nitrogen (BUN), serum creatinine, and 24-hour urine albumin were used to evaluate renal function. Western blot was used to detect fibrosis-related protein, inflammatory mediators, high mobility group box 1 (HMGB1)/NF-κB signal pathway molecule, vascular endothelial growth factor (VEGF), and podocin, and immunohistochemistry (IHC) was used to detect the expression and localization of autophagy-related protein and fibronectin.

Results

Compared with the kidney of normal control mice, the kidney of diabetes control mice was more pale and hypertrophic. Hyperglycemia induces renal autophagy and activates the HMGB1/NF-κB signal pathway, leading to the increase of inflammatory mediators, extracellular matrix (ECM) deposition, and proteinuria in the kidney. In diabetic mice treated with 3-MA, blood glucose decreased, autophagy and HMGB1/NF-κB signaling pathways in the kidneys were inhibited, and proteinuria, renal hypertrophy, inflammation, and fibrosis were improved.

Conclusion

3-MA can attenuate renal injury in STZ-induced diabetic mice through inhibition of autophagy and HMGB1/NF-κB signaling pathway.

Histone demethylase KDM4B contributes to advanced clear cell renal carcinoma and association with copy number variations and cell cycle progression

Advanced renal cell carcinoma (RCC) poses a threat to patient survival. Epigenetic remodelling is the pathogenesis of renal cancer. Histone demethylase 4B (KDM4B) is overexpressed in many cancers through various pathways. However, the role of KDM4B in clear cell renal carcinoma has not yet been elucidated. The differential expression of KDM4B was first verified by analysing public databases. The expression of KDM4B in fresh tissues and pathology slides was further analysed by western blotting and immunohistochemical staining. KDM4B overexpression and knockdown cell lines were also established. Cell Counting Kit-8 (CCK-8) assay was used to detect cell growth. Transwell assays were performed to assess cell migration. Xenografts were used to evaluate tumour growth and metastasis in vivo. Finally, KDM4B expression levels associated with copy number variation (CNV) and cell cycle stage were evaluated based on single-cell RNA sequencing data. KDM4B was expressed at higher levels in tumour tissues than in the adjacent normal tissues. High levels of KDM4B are associated with worse pathological features and poorer prognosis. KDM4B also promotes cell proliferation and migration in vitro, as well as tumour growth and metastasis in vivo. Tumour cells with high KDM4B expression exhibited higher CNV levels and a greater proportion of cells in the G1/S transition phase. Our results confirm that KDM4B promotes the progression of clear cell renal carcinoma, is correlated with poor prognosis, and may be related to high levels of CNV and cell cycle progression.

The effect of lipid metabolism disorder on patients with hyperuricemia using Multi-Omics analysis

A multiomics study was conducted to investigate how lipid metabolism disorders affect the immune system in Xinjiang patients with hyperuricemia. The serum of 60 healthy individuals and 60 patients with hyperuricemia was collected. This study used LC-MS and HPLC to analyze differential lipid metabolites and enrichment pathways. It measured levels of immune factors tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), carnitine palmitoyltransferase-1 (CPT1), transforming growth factor-β1 (TGF-β1), glucose (Glu), lactic acid (LD), interleukin 10 (IL-10), and selenoprotein 1 (SEP1) using ELISA, as well as to confirm dysregulation of lipid metabolism in hyperuricemia. 33 differential lipid metabolites were significantly upregulated in patients with hyperuricemia. These lipid metabolites were involved in arachidonic acid metabolism, glycerophospholipid metabolism, linoleic acid metabolism, glycosylphosphatidylinositol (GPI)-anchor biosynthesis, and alpha-Linolenic acid metabolism pathways. Moreover, IL-10, CPT1, IL-6, SEP1, TGF-β1, Glu, TNF-α, and LD were associated with glycerophospholipid metabolism. In patients with hyperuricemia of Han and Uyghur nationalities, along with healthy individuals, significant differences in CPT1, TGF-β1, Glu, and LD were demonstrated by ELISA (P < 0.05). Furthermore, the levels of SEP1, IL-6, TGF-β1, Glu, and LD differed considerably between groups of the same ethnicity (P < 0.05). It was found that 33 kinds of lipid metabolites were significantly different in patients with hyperuricemia, which mainly involved 5 metabolic pathways. According to the results of further studies, it is speculated that CPT1, TGF-β1, SEP1, IL-6, Glu and LD may increase fatty acid oxidation and mitochondrial oxidative phosphorylation in patients through glycerophospholipid pathway, reduce the rate of glycolysis, and other pathways to change metabolic patterns, promote different cellular functions, and thus affect the disease progression in patients with hyperuricemia.

Autophagy and Biomaterials: A Brief Overview of the Impact of Autophagy in Biomaterial Applications

Macroautophagy (hereafter autophagy), a tightly regulated physiological process that obliterates dysfunctional and damaged organelles and proteins, has a crucial role when biomaterials are applied for various purposes, including diagnosis, treatment, tissue engineering, and targeted drug delivery. The unparalleled physiochemical properties of nanomaterials make them a key component of medical strategies in different areas, such as osteogenesis, angiogenesis, neurodegenerative disease treatment, and cancer therapy. The application of implants and their modulatory effects on autophagy have been known in recent years. However, more studies are necessary to clarify the interactions and all the involved mechanisms. The advantages and disadvantages of nanomaterial-mediated autophagy need serious attention in both the biological and bioengineering fields. In this mini-review, the role of autophagy after biomaterial exploitation and the possible related mechanisms are explored.

An ultrasmall PVP-Fe-Cu-Ni-S nano-agent for synergistic cancer therapy through triggering ferroptosis and autophagy

Photothermal therapy (PTT) is an emerging field where photothermal agents could convert visible or near-infrared (NIR) radiation into heat to kill tumor cells. However, the low photothermal conversion efficiency of photothermal agents and their limited antitumor activities hinder the development of these agents into monotherapies for cancer. Herein, we have fabricated an ultrasmall polyvinylpyrrolidone (PVP)-Fe-Cu-Ni-S (PVP-NP) nano-agent via a simple hot injection method with excellent photothermal conversion efficiency (∼96%). Photothermal therapy with this nano-agent effectively inhibits tumor growth without apparent toxic side-effects. Mechanistically, our results demonstrated that, after NIR irradiation, PVP-NPs can induce ROS/singlet oxygen generation, decrease the mitochondrial membrane potential, release extracellular Fe2+, and consume glutathione, triggering autophagy and ferroptosis of cancer cells. Moreover, PVP-NPs exhibit excellent contrast enhancement according to magnetic resonance imaging (MRI) analysis. In summary, PVP-NPs have a high photothermal conversion efficiency and can be applied for MRI-guided synergistic photothermal/photodynamic/chemodynamic cancer therapy, resolving the bottleneck of existing phototherapeutic agents.

Embryo-derive TNF promotes decidualization via fibroblast activation

Decidualization is a process in which endometrial stromal fibroblasts differentiate into specialized secretory decidual cells and essential for the successful establishment of pregnancy. The underlying mechanism during decidualization still remains poorly defined. Because decidualization and fibroblast activation share similar characteristics, this study was to examine whether fibroblast activation is involved in decidualization. In our study, fibroblast activation-related markers are obviously detected in pregnant decidua and under in vitro decidualization. ACTIVIN A secreted under fibroblast activation promotes in vitro decidualization. We showed that arachidonic acid released from uterine luminal epithelium can induce fibroblast activation and decidualization through PGI₂ and its nuclear receptor PPARδ. Based on the significant difference of fibroblast activation-related markers between pregnant and pseudopregnant mice, we found that embryo-derived TNF promotes CPLA_2α phosphorylation and arachidonic acid release from luminal epithelium. Fibroblast activation is also detected under human in vitro decidualization. Similar arachidonic acid-PGI₂-PPARδ-ACTIVIN A pathway is conserved in human endometrium. Collectively, our data indicate that embryo-derived TNF promotes CPLA_2α phosphorylation and arachidonic acid release from luminal epithelium to induce fibroblast activation and decidualization.

Qinling liquid ameliorates renal immune inflammatory damage via activating autophagy through AMPK/Stat3 pathway in uric acid nephropathy

BACKGROUND

Excessive deposition of uric acid (UA) is one of the risk factors for kidney damage. Qinling liquid (QL) has a certain therapeutic effect on uric acid nephropathy (UAN), but its regulation mechanism is still unclear.

METHODS

UAN rat models and UA induced rat renal tubular epithelial cells (NRK-52E) were constructed to evaluate the functional roles of QL. We firstly evaluated the kidney function and the degree of kidney damage in rats after QL treatment. Then, effects of QL on autophagy and NLRP3 inflammasome activation were assessed. Moreover, the regulation of QL in AMPK and Stat3 phosphorylation levels and the relationship among autophagy, AMPK/Stat3 pathway and NLRP3 inflammasomes were determined.

RESULTS

QL could alleviate the inflammatory damage in UAN rats and promote the activation of autophagy. In addition, QL suppressed UA-induced activation of NLRP3 inflammasomes in rat renal tubular epithelial cells, which was partially reversed by autophagy inhibitor. Further, AMPK/Stat3 axis-mediated autophagy participated in the regulation of UA-induced NLRP3 inflammasome activation in NRK-52E cells. Finally, we confirmed that inhibiting AMPK/Stat3 pathway partly deteriorated the ameliorating effect of QL on renal immune inflammatory injury in UAN rats.

CONCLUSION

Through in vivo and in vitro experiments, we found that QL promotes autophagy by activating the AMPK/Stat3 pathway, thereby improving renal immune inflammatory injury in UAN.

Combination of DNA Damage, Autophagy, and ERK Inhibition: Novel Evodiamine-Inspired Multi-Action Pt(IV) Prodrugs with High-Efficiency and Low-Toxicity Antitumor Activity

Exploring multi-targeting chemotherapeutants with advantages over single-targeting agents and drug combinations is of great significance in drug discovery. Herein, we employed phytogenic evodiamine (EVO) and conventional Pt(II) drugs to design and synthesize multi-target EVO-Pt(IV) anticancer prodrugs (4-14). Among them, compound 10 exhibited a 118-fold enhancement in the IC₅₀ value compared to cisplatin and low toxicity to normal cells. Further studies proved that 10 significantly enhanced intracellular Pt accumulation and DNA damage, perturbed mitochondrial membrane potential, inhibited cell migration and invasion, upregulated reactive oxygen species levels, and induced apoptosis and autophagic cell death. Molecular docking assay revealed that 10 fits perfectly into the extracellular signal-regulated protein kinase (ERK)-1 pocket, which was verified to produce profound ERK suppression. Most strikingly, compound 10 exhibited superior in vivo antitumor efficiency and effectively attenuated systemic toxicity. Our results emphasize that functionalizing platinum drugs with the multi-target EVO could generate synergistically excellent anticancer activity with low toxicity and decreased resistance, which may represent a brand-new cancer therapy modality.

Therapeutic effects of traditional Chinese medicine on gouty nephropathy: Based on NF-κB signalingpathways

As the final product of purine metabolism, excess serum uric acid (SUA) aggravates the process of some metabolic diseases. SUA causes renal tubule damage, interstitial fibrosis, and glomerular hardening, leading to gouty nephropathy (GN). A growing number of investigations have shown that NF-κB mediated inflammation and oxidative stress have been directly involved in the pathogenesis of GN. Traditional Chinese medicine's treatment methods of GN have amassed a wealth of treatment experience. In this review, we first describe the mechanism of NF-κB signaling pathways in GN. Subsequently, we highlight traditional Chinese medicine that can treat GN through NF-κB pathways. Finally, commenting on promising candidate targets of herbal medicine for GN treatment via suppressing NF-κB signaling pathways was summarized.

Autophagy as a Therapeutic Target for Chronic Kidney Disease and the Roles of TGF-β1 in Autophagy and Kidney Fibrosis

Autophagy is a lysosomal protein degradation system that eliminates cytoplasmic components such as protein aggregates, damaged organelles, and even invading pathogens. Autophagy is an evolutionarily conserved homoeostatic strategy for cell survival in stressful conditions and has been linked to a variety of biological processes and disorders. It is vital for the homeostasis and survival of renal cells such as podocytes and tubular epithelial cells, as well as immune cells in the healthy kidney. Autophagy activation protects renal cells under stressed conditions, whereas autophagy deficiency increases the vulnerability of the kidney to injury, resulting in several aberrant processes that ultimately lead to renal failure. Renal fibrosis is a condition that, if chronic, will progress to end-stage kidney disease, which at this point is incurable. Chronic Kidney Disease (CKD) is linked to significant alterations in cell signaling such as the activation of the pleiotropic cytokine transforming growth factor-β1 (TGF-β1). While the expression of TGF-β1 can promote fibrogenesis, it can also activate autophagy, which suppresses renal tubulointerstitial fibrosis. Autophagy has a complex variety of impacts depending on the context, cell types, and pathological circumstances, and can be profibrotic or antifibrotic. Induction of autophagy in tubular cells, particularly in the proximal tubular epithelial cells (PTECs) protects cells against stresses such as proteinuria-induced apoptosis and ischemia-induced acute kidney injury (AKI), whereas the loss of autophagy in renal cells scores a significant increase in sensitivity to several renal diseases. In this review, we discuss new findings that emphasize the various functions of TGF-β1 in producing not just renal fibrosis but also the beneficial TGF-β1 signaling mechanisms in autophagy.

Ropivacaine inhibits proliferation and invasion and promotes apoptosis and autophagy in bladder cancer cells via inhibiting PI3K/AKT pathway

Application of a certain concentration of local anesthetics during tumor resection inhibits the progression of tumor. The effects of ropivacaine in bladder cancer (BC) have never been explored. We explored the effects of ropivacaine on the progression of BC in vitro and in vivo. CCK8 assay and EDU staining was conducted to examine cell proliferation. Flow cytometry and transwell assay were performed to evaluate apoptosis and invasion, respectively. Expression of light chain 3 (LC3) was observed through immunofluorescence. Furthermore, the xenograft tumor model of BC was built to detect the effects of ropivacaine in vivo. IHC and TUNEL assay were conducted to detect cell proliferation and apoptosis in vivo. Ropivacaine inhibited the proliferation of T24 and 5639 cells with the 50% inhibitory concentration (IC50) of 20.08 and 31.86 µM, respectively. Ropivacaine suppressed the invasion ability and induces the apoptosis of cells. Besides, ropivacaine triggers obvious autophagy in BC cells. Moreover, ropivacaine blocks the PI3K/AKT signal pathway in BC cells. The impact of ropivacaine on cell viability, motility, and autophagy was reversed by 740 Y-P, the activator of PI3K/AKT signal pathway. The in vivo experiments demonstrated that ropivacaine inhibited the proliferation and mobility of BC. Ropivacaine has anti-carcinoma effects in BC via inactivating PI3K/AKT pathway, providing a new theoretical reference for the use of local anesthetics in the treatment of BC.

Combined exposure to di(2-ethylhexyl) phthalate and polystyrene microplastics induced renal autophagy through the ROS/AMPK/ULK1 pathway

Di(2-ethylhexyl) phthalate (DEHP) and polystyrene microplastics (PS-MPs) are new environmental pollutants that attracted increased attention. At present, the effects and underlying mechanisms of action of combined exposure of DEHP and PS-MPs on the kidney have not been elucidated. To investigate the renal toxicity of DEHP and PS-MPs exposure, we established single and combined DEHP and PS-MPs exposure models in mice and HEK293 cells, respectively. Hematoxylin and eosin staining, transmission electron microscopy, monodansylcadaverine staining, immunofluorescence, real-time quantitative PCR, Western blot analysis and other methods were used to detect relevant indicators. The results showed that the expression levels of ROS/AMPK/ULK1 and Ppargc1α/Mfn2 signaling pathway-related genes were significantly increased in the DEHP and PS-MPs exposure models. The mRNA and protein expression levels of autophagy markers were also upregulated. In addition, we found that the expression levels of mRNAs and proteins in the combined exposure group were more significantly increased than those in the single exposure group. In conclusion, combined exposure to DEHP and PS-MPs caused oxidative stress and activated the AMPK/ULK1 pathway, thereby inducing renal autophagy. Our results enhance the field of nephrotoxicity studies of plasticizers and microplastics and provide new light on combined toxicity studies of DEHP and PS-MPs.

Fibroblast Growth Factor 21 Attenuates the Progression of Hyperuricemic Nephropathy through Inhibiting Inflammation, Fibrosis and Oxidative stress

Elevated levels of circulating fibroblast growth factor 21 (FGF21) have been reported in patients with hyperuricemia. However, the effect of FGF21 in hyperuricemic nephropathy (HN) remains unexplored. Here, we investigated the effect and mechanism of action of FGF21 on HN. HN model was induced with adenine and potassium oxysalt in wild-type C57BL/6 mice and FGF21^-/- mice. For in vitro studies, human renal tubular epithelial (HK-2) cells were exposed to uric acid with/without FGF21 or β-Klotho-siRNA. Here, we reported aggravated renal dysfunction and structural damage in the FGF21^-/- mice compared to the wild-type mice. These were evident in the upsurge of inflammatory factors IL-1β, TNF-α, IL-6 and IL-18, fibrotic markers Collagen I and α-SMA, and oxidation products ROS and MDA. However, exogenous administration of FGF21 to wild-type HN mice significantly reversed these negative effects. In terms of mechanism, FGF21 significantly inhibited NF-κB/NLRP3 and TGF-β1/Smad3 pathways and promoted nuclear translocation of Nrf2 both in vivo and in vitro. Furthermore, the silencing of β-Klotho was marked by the attenuation of the improved effect of FGF21 on cell damage. In conclusion, our studies revealed that exogenous FGF21 treatment significantly improved HN, which was achieved by the inhibition of inflammation, fibrosis and oxidative stress.

Autophagy-dependent Na+-K+-ATPase signalling and abnormal urate reabsorption in hyperuricaemia-induced renal tubular injury

Increasing evidence indicates that hyperuricaemia (HUA) is not only a result of decreased renal urate excretion but also a contributor to kidney disease. Na⁺-K⁺-ATPase (NKA), which establishes the sodium gradient for urate transport in proximal tubular epithelial cells (PTECs), its impairment leads to HUA-induced nephropathy. However, the specific mechanism underlying NKA impairment-mediated renal tubular injury and increased urate reabsorption in HUA is not well understood. In this study, we investigated whether autophagy plays a key role in the NKA impairment signalling and increased urate reabsorption in HUA-induced renal tubular injury. Protein spectrum analysis of exosomes from the urine of HUA patients revealed the activation of lysosomal processes, and exosomal expression of lysosome membrane protein 2 was associated with increased serum levels and decreased renal urate excretion in patients. We demonstrated that high uric acid (UA) induced lysosome dysfunction, autophagy and inflammation in a time- and dose-dependent manner and that high UA and/or NKA α1 siRNA significantly increased mitochondrial abnormalities, such as reductions in mitochondrial respiratory complexes and cellular ATP levels, accompanied by increased apoptosis in cultured PTECs. The autophagy inhibitor hydroxychloroquine (HCQ) ameliorated NKA impairment-mediated mitochondrial dysfunction, Nod-like receptor pyrin domain-containing protein 3 (NLRP3)-interleukin-1β (IL-1β) production, and abnormal urate reabsorption in PTECs stimulated with high UA and in rats with oxonic acid (OA)-induced HUA. Our findings suggest that autophagy plays a pivotal role in NKA impairment-mediated signalling and abnormal urate reabsorption in HUA-induced renal tubular injury and that inhibition of autophagy by HCQ could be a promising treatment for HUA.

Inhibiting Cytoprotective Autophagy in Cancer Therapy: An Update on Pharmacological Small-Molecule Compounds

Autophagy is a self-degradation process in which damaged proteins and organelles are engulfed into autophagosomes for digestion and eventually recycled for cellular metabolism to maintain intracellular homeostasis. Accumulating studies have reported that autophagy has the Janus role in cancer as a tumor suppressor or an oncogenic role to promote the growth of established tumors and developing drug resistance. Importantly, cytoprotective autophagy plays a prominent role in many types of human cancers, thus inhibiting autophagy, and has been regarded as a promising therapeutic strategy for cancer therapy. Here, we focus on summarizing small-molecule compounds inhibiting the autophagy process, as well as further discuss other dual-target small-molecule compounds, combination strategies, and other strategies to improve potential cancer therapy. Therefore, these findings will shed new light on exploiting more small-molecule compounds inhibiting cytoprotective autophagy as candidate drugs for fighting human cancers in the future.

Spiropachysine A suppresses hepatocellular carcinoma proliferation by inducing methuosis in vitro and in vivo

BACKGROUND

Spiropachysine A is the extracted compound of traditional Chinese ethnic medicine Pachysandra axillaries Franch. var. styiosa (Dunn) M. Cheng. Spiropachysine A is the primary active steroidal alkaloids (SAs) widely used to facilitate blood circulation and relieve pain and inflammation. Few previous studies have investigated the anti-cancer activity of Spiropachysine A to treat hepatocellular carcinoma (HCC), and its molecular mechanism remains unknown.

PURPOSE

This study aims to investigate the anti-cancer activity of Spiropachysine A and the underlying mechanisms by inducing methuosis in vitro and in vivo.

METHODS

Here, the activity of Spiropachysine A against cancer was evaluated by the experiments with MHCC-97H cells and the xenografted mice model. The cell proliferation was examined using MTT assay, and cell morphological characteristics were observed by microscope cellular imaging. The effects of autophagy, paraptosis, and oncosis on cytoplasmic vacuolisation were detected using immunofluorescence staining, transmission electron microscopy (TEM) and western blotting (WB). The cell cycle distribution and apoptosis were analysed by flow cytometry. Hematoxylin eosin (H & E) staining was used to observe the pathological changes of the tissues.

RESULTS

The in vitro and in vivo results indicated that Spiropachysine A could inhibit HCC cells proliferation (IC₅₀ = 2.39 ± 0.21 μM against MHCC-97H cells) and tumor growth (TGI = 32.81 ± 0.23% at 25 mg/kg and 50.32 ± 0.26% at 50 mg/kg). The morphological changes of the treated cells showed that cell proliferation inhibition caused by Spiropachysine A was associated with numerous cytoplasmic vacuolization. Mechanistically, Spiropachysine A-induced methuosis rather than autophagy or arapaptic because the autophagy flux was blocked, leading to the increased LC3-II/I value and an accumulation of selective autophagy substrate p62. And, there was no activation of the regulatory parapaptic MAPK pathway. Additionally, the TEM and Lucifer yellow (LY) accumulation data confirmed that Spiropachysine A significantly triggered methuosis instead of oncosis. Further, the study indicated that the anti-proliferative activity of Spiropachysine A was independent of PCD since no alterations in apoptosis and cell cycle arrest-related proteins were observed after Spiropachysine A treatment. Impressively, the increased expression of Rac1 was observed in Spiropachysine A-treated MHCC-97H cells and its xenograft tumours, confirming that Spiropachysine A inhibited cell proliferation and induced methuosis through Ras/Rac1 signal pathways.

CONCLUSIONS

Spiropachysine A was collectively identified as a novel methuosis inducer that suppresses HCC in vitro and in vivo. The underlying mechanisms might be involved in the Ras/Rac1 pathway. Such data predict that Spiropachysine A is a promising candidate for developing novel chemotherapeutic agents as a methuosis inducer for cancer therapy.

Blockade of Autophagy Prevents the Progression of Hyperuricemic Nephropathy Through Inhibiting NLRP3 Inflammasome-Mediated Pyroptosis

Hyperuricemia has become a common metabolic disease, and is a risk factor for multiple diseases, including chronic kidney disease. Our recent study indicated that following persistent uric acid stimulation, autophagy was activated in rats of hyperuricemic nephropathy (HN) and facilitated the development of renal fibrosis. Nevertheless, the potential mechanism by which autophagy promoted the progression of HN is still not fully elucidated. Thus, in the current study, we investigated the mechanisms of autophagy inhibition on the development of HN. Our data showed that autophagy was activated in human renal tubular cell lines (HK-2) exposure to uric acid. Inhibition of autophagy with 3-methyladenine (3-MA) and transfected with Beclin-1 siRNA prevented uric acid-induced upregulation of α-SMA, Collagen I and Collagen III in HK-2 cells. Moreover, uric acid upregulated autophagy via promoting the p53 pathway. In vivo, we showed that hyperuricemic injury induced the activation of NLRP3 inflammasome and pyroptosis, as evidenced by cleavage of caspase-1 and caspase-11, activation of gasdermin D (GSDMD) and the release of IL-1β and IL-18. Treatment with autophagy inhibitor 3-MA alleviated aforementioned phenomenon. Stimulation with uric acid in HK-2 cells also resulted in NLRP3 inflammasome activation and pyroptotic cell death, however treatment with 3-MA prevented all these responses. Mechanistically, we showed that the elevation of autophagy and degradation of autophagolysosomes resulted in the release of cathepsin B (CTSB), which is related to the activation of NLRP3 inflammasome. CTSB siRNA can inhibit the activation of NLRP3 inflammasome and pyroptosis. Collectively, our results indicate that autophagy inhibition protects against HN through inhibiting NLRP3 inflammasome-mediated pyroptosis. What’s more, blockade the release of CTSB plays a crucial role in this process. Thus, inhibition of autophagy may be a promising therapeutic strategy for hyperuricemic nephropathy.

Autophagy protects against high uric acid-induced hepatic insulin resistance

Uric acid (UA), the end-product of purine metabolism, is closely related to hepatic insulin resistance (IR). Autophagy is a conserved intracellular degradation process maintaining cellular homeostasis. Autophagy plays a protective role in obesity-related hepatic IR, but whether it occurs in high uric acid (HUA)-induced hepatic IR is unclear. In this study, spontaneously elevated UA level induced hepatic IR and facilitated hepatic autophagy degradation in uricase knockout (Uox^-/-) mice. In vitro, HepG2 cells stimulated with HUA medium showed decreased glucose uptake and inhibition of insulin signaling pathways, concomitant with activation of autophagy, as manifested by increased conversion of LC3B-I to -II. Rapamycin, the autophagy activator, alleviated but the autophagy inhibitor trimethyl adenine (3-MA) aggravated HUA-induced IR in HepG2 cells. Similarly, rapamycin ameliorated and 3-MA worsened HUA-induced blood glucose level and hepatic IR in Uox^-/- mice. Mechanistically, HUA enhanced AMPKα phosphorylation (p-AMPKα) and inhibited mammalian target of rapamycin phosphorylation (p-mTOR) in HepG2 cells. The levels of p-AMPKα and LC3B-II/I were downregulated in HepG2 cells transfected with small interfering RNA (siRNA) against AMPKα, which suggests that the AMPKα-mTOR pathway was involved in HUA-induced autophagy. Antioxidant N-acetyl-L-cysteine reversed elevated reactive oxygen species levels induced by HUA in HepG2 cells, and AMPKα level was also inhibited, which suggests that AMPKα activation may be derived from reactive oxygen species. Collectively, these findings demonstrate that HUA increased hepatic autophagy, and autophagy activation plays a protective role in hepatic IR, which may suggest a potential therapeutic target for hepatic IR derived from HUA.

Implication of autophagy in the antifibrogenic effect of Rilpivirine: when more is less

As the main extracellular matrix-producing cells, activated hepatic stellate cells (HSC) are fundamental mediators of liver fibrosis (LF), and understanding their activation/inactivation mechanisms is paramount to the search for novel therapeutics. The antiretroviral drug Rilpivirine (RPV) has demonstrated a hepatoprotective effect in several animal models of chronic liver injury that is related to its antifibrogenic and apoptotic action in HSC. In the present study, we evaluated whether autophagy is implicated in the hepatoprotective action of RPV, as autophagy plays an important role in HSC transdifferentiation. We employed two standard mouse models of chronic liver injury - fatty liver disease and carbon tetrachloride (CCl₄)-induced hepatotoxicity -and cultured HSC activated with the profibrotic cytokine TGF-β. RPV enhanced autophagy in the whole liver of both mouse models and in activated HSC, evident in the protein expression of autophagy markers, increased autophagosome content and lysosomal mass. Moreover, increased autophagic flux was observed in RPV-exposed HSC as revealed by tandem fluorescence-tagged LC3 and p62 and analysis of LC3-II accumulation in cells exposed to the lysosomal inhibitor chloroquine. Importantly, autophagy was involved in the cytotoxic effect of RPV on HSC, though in a differential manner. Pharmacological inhibition of autophagy by 3-methyladenine (3-MA) did not affect the diminishing effect of RPV on viability, while treatment with wortmannin or depletion of specific autophagy proteins (ATG5, Beclin-1 and SQSTM1/p62) rescued the detrimental effect of high concentrations of RPV on the viability of activated HSC. Finally, we also provide evidence that RPV compromises the viability of TGF-β-induced HSC independently of its antifibrogenic effect, observed as reduced collagen 1A1 synthesis, and that this effect does not include RPV´s modulation of autophagy. In summary, as a contributor to the mechanisms involved in the hepatoprotective action of RPV, autophagy may be a good candidate to explore when developing novel therapeutics for LF.

Cordyceps cicadae Ameliorates Renal Hypertensive Injury and Fibrosis Through the Regulation of SIRT1-Mediated Autophagy

Hypertensive renal injury is a complication of hypertension. Cordyceps cicadae (C. cicadae) is a traditional Chinese medicine used to treat chronic kidney diseases especially renal fibrosis. Autophagy is described as a cell self-renewal process that requires lysosomal degradation and is utilized for the maintenance of cellular energy homeostasis. The present study explores the mechanism underlying C. cicadae’s renoprotection on hypertensive nephropathy (HN). First, HN rat models were established on spontaneously hypertensive rats (SHRs). The expression of fibrosis-related protein and autophagy-associated protein was detected in vivo. NRK-52E cells exposed to AngII were chosen to observe the potential health benefits of C. cicadae on renal damage. The level of extracellular matrix accumulation was detected using capillary electrophoresis immunoquantification and immunohistochemistry. After treatment with lysosomal inhibitors (chloroquine) or an autophagy activator (rapamycin), the expression of Beclin-1, LC3II, and SQSTM1/p62 was further investigated. The study also investigated the change in sirtuin1 (SIRT1), fork head box O3a (FOXO3a), and peroxidation (superoxide dismutase (SOD) and malondialdehyde (MDA)) expression when intervened by resveratrol. The changes in SIRT1 and FOXO3a were measured in patients and the SHRs. Here, we observed that C. cicadae significantly decreased damage to renal tubular epithelial cells and TGFβ1, α-smooth muscle actin (α-SMA), collagen I (Col-1), and fibronectin expression. Meanwhile, autophagy defects were observed both in vivo and in vitro. C. cicadae intervention significantly downregulated Beclin-1 and LC3II and decreased SQSTM1/p62, showing an inhibition of autophagic vesicles and the alleviation of autophagy stress. These functions were suppressed by rapamycin, and the results were just as effective as the resveratrol treatment. HN patients and the SHRs exhibited decreased levels of SIRT1 and FOXO3a. We also observed a positive correlation between SIRT1/FOXO3a and antifibrotic effects. Similar to the resveratrol group, the expression of SIRT1/FOXO3a and oxidative stress were elevated by C. cicadae in vivo. Taken together, our findings show that C. cicadae ameliorates tubulointerstitial fibrosis and delays HN progression. Renoprotection was likely attributable to the regulation of autophagic stress mediated by the SIRT1 pathway and achieved by regulating FOXO3a and oxidative stress.

Anti-Fibrotic Effect of Synthetic Noncoding Oligodeoxynucleotide for Inhibiting mTOR and STAT3 via the Regulation of Autophagy in an Animal Model of Renal Injury

Renal fibrosis is a common process of various kidney diseases. Autophagy is an important cell biology process to maintain cellular homeostasis. In addition, autophagy is involved in the pathogenesis of various renal disease, including acute kidney injury, glomerular diseases, and renal fibrosis. However, the functional role of autophagy in renal fibrosis remains poorly unclear. The mammalian target of rapamycin (mTOR) plays a negative regulatory role in autophagy. Signal transducer and activator of transcription 3 (STAT3) is an important intracellular signaling that may regulate a variety of inflammatory responses. In addition, STAT3 regulates autophagy in various cell types. Thus, we synthesized the mTOR/STAT3 oligodeoxynucleotide (ODN) to regulate the autophagy. The aim of this study was to investigate the beneficial effect of mTOR/STAT3 ODN via the regulation of autophagy appearance on unilateral ureteral obstruction (UUO)-induced renal fibrosis. This study showed that UUO induced inflammation, tubular atrophy, and tubular interstitial fibrosis. However, mTOR/STAT3 ODN suppressed UUO-induced renal fibrosis and inflammation. The autophagy markers have no statistically significant relation, whereas mTOR/STAT3 ODN suppressed the apoptosis in tubular cells. These results suggest the possibility of mTOR/STAT3 ODN for preventing renal fibrosis. However, the role of mTOR/STAT3 ODN on autophagy regulation needs to be further investigated.

Icariin activates autophagy to trigger TGFβ1 upregulation and promote angiogenesis in EA.hy926 human vascular endothelial cells

Angiogenesis plays an important role in tissue development and repair, and how to regulate angiogenesis effectively is a widely studied problem in the biomedical field. In recent years, the role of autophagy in vascular endothelial cells has attracted extensive attention. Icariin (ICA) is a traditional Chinese medicine that has been proven to have outstanding protective effects on the vascular system and to regulate cellular autophagy effectively. However, at present, it has not been reported whether ICA can affect the angiogenic ability of endothelial cells by affecting autophagy. In this study, we aimed to investigate whether ICA affects the angiogenesis capacity of EA.hy926 human vascular endothelial cells through autophagy and explain the underlying potential mechanisms. First, we determined that ICA at appropriate concentrations has the ability to promote cell migration and angiogenesis using wound healing assays and tube formation assays. Then, at the molecular level, we observed the upregulation of VEGFA, VEGFR2, ANGI, ANGII, and Tie2 mRNA and detected the upregulation of TGFβ1 protein by Western blotting. We also demonstrated that angiogenic concentrations of ICA can effectively activate autophagy. The autophagy inhibitor 3-MA significantly suppressed TGFβ1 expression and tube formation in EA.hy926 cells. Overall, we hope that our studies might help to further understand the effect of ICA on vascular endothelial cells and provide a theoretical basis for future angiogenic applications of ICA

Quercetin promotes locomotor function recovery and axonal regeneration through induction of autophagy after spinal cord injury

Quercetin (Que), one of the flavonoids, exerts numerous actions on the central nervous system. However, the roles and underlying mechanism of Que in locomotor function recovery and axonal regeneration following spinal cord injury (SCI) have not been fully elucidated. A rat model of spinal cord injury (SCI) was established at T10 using the modified Allen's method. The results in our study indicated that Basso, Beattie and Bresnahan (BBB) locomotor scores were significantly higher after Que treatment. Additionally, Que administration cut down the latency of somatosensory evoked potentials (SEP) and motor evoked potentials (MEP), increased the amplitude of MEP and SEP following SCI. Hematoxylin-eosin (HE) staining demonstrated that Que administration reduced lesion size and cavity formation. Biotinylated dextran amine (BDA) anterograde tracing revealed that BDA positive fibres were increased by Que following SCI. Immunofluorescence staining revealed that Que elevated 5-hydroxytryptamine (5-HT) positive nerve fibres and neurofilament-200 (NF-200) positive neurons, reduced glial fibrillary acidic protein (GFAP) positive astrocytes. In addition, Que inhibited GFAP expression, increased both NeuN and NF-200 expression and facilitated the spinal cord energy metabolism. Moreover, Que increased 18 F-FDG uptake in a time-dependent manner. Furthermore, Que increased Beclin 1 and LC3 II expression, blocked the phosphorylation of Akt, mTOR and p70S6K. 3-methyladenine (3-MA) partly abolished the neuro-protective roles of Que following SCI. Taken together, our study suggested that Que might promote locomotor function recovery, axonal regeneration and energy metabolism through induction of autophagy via Akt/mTOR/p70S6K pathway.

The Complex Interplay between Autophagy and NLRP3 Inflammasome in Renal Diseases

Autophagy is a highly conserved process of the eukaryotic cell cycle. It plays an important role in the survival and maintenance of cells by degrading organelles, proteins, and macromolecules in the cytoplasm and the circulation of degraded products. The dysfunction of autophagy can lead to the pathology of many human diseases. The nucleotide-binding oligomerization domain-like receptor family, pyrin domain-containing 3 (NLRP3) inflammasome belongs to the family of nucleotide-binding and oligomerization domain-like receptors (NLRs) and can induce caspase-1 activation, thus leading to the maturation and secretion of interleukin-1beta (IL-1β) and IL-18. It has been reported that the interplay between autophagy and NLRP3 inflammasome is involved in many diseases, including renal diseases. In this review, the interplay between autophagy and the NLRP3 inflammasome and the mechanisms in renal diseases are explored to provide ideas for relevant basic research in the future.

Autophagy in Cisplatin Nephrotoxicity during Cancer Therapy

Cisplatin is a widely used chemotherapeutic agent but its clinical use is often limited by nephrotoxicity. Autophagy is a lysosomal degradation pathway that removes protein aggregates and damaged or dysfunctional cellular organelles for maintaining cell homeostasis. Upon cisplatin exposure, autophagy is rapidly activated in renal tubule cells to protect against acute cisplatin nephrotoxicity. Mechanistically, the protective effect is mainly related to the clearance of damaged mitochondria via mitophagy. The role and regulation of autophagy in chronic kidney problems after cisplatin treatment are currently unclear, despite the significance of research in this area. In cancers, autophagy may prevent tumorigenesis, but autophagy may reduce the efficacy of chemotherapy by protecting cancer cells. Future research should focus on developing drugs that enhance the anti-tumor effects of cisplatin while protecting kidneys during cisplatin chemotherapy.

Mesenchymal stem cells transplantation attenuates hyperuricemic nephropathy in rats

Mesenchymal stem cells (MSCs), due to their multi-directional differentiation, paracrine and immunomodulation potentials, and the capacity of homing to target organ, have been reported to facilitate regeneration and repair of kidney and improve kidney function in acute or chronic kidney injury. The present study was aimed to evaluate whether MSCs could have a protective effect in hyperuricemic nephropathy (HN) and the underlying mechanisms. A rat HN model was established by oral administration of a mixture of potassium oxonate (PO, 1.5 g/kg) and adenine (Ad, 50 mg/kg) daily for 4 weeks. For MSCs treatment, MSCs (3 × 10⁶ cells/kg per week) were injected via tail vein from the 2nd week for 3 times. The results showed that along with the elevated uric acid (UA) in HN rats, creatinine (CREA), blood urea nitrogen (BUN), microalbuminuria (MAU) and 24-hour urinary protein levels were significantly increased comparing with the normal control rats, while decreased after MSCs treatment. Moreover, the mRNA levels of inflammation and fibrosis-related gene were reduced in UA + MSCs group. Consistently, hematoxylin-eosin (HE) staining results showed the destruction of kidney structure and fibrosis were significantly alleviated after MSCs administration. Similarly, in vitro, NRK-52Es cells were treated with high concentration UA (10 mg/dL) in the presence of MSCs, and we found that MSCs co-culture could inhibited UA-induced cell injury, characterized as improvement of cell viability and proliferation, inhibition of apoptosis, inflammation, and fibrosis. Collectively, MSCs treatment could effectively attenuate UA-induced renal injury, and thus it might be a potential therapy to hyperuricemia-related renal diseases.

Curcumin modulates gut microbiota and improves renal function in rats with uric acid nephropathy

It is well known that the progression of hyperuricemia disease often contributes to renal dysfunction. However, there have been few studies on uric acid nephropathy (UAN), especially its relationship with gut microbiota. UAN is usually accompanied by disordered intestinal flora, and damaged gut barrier, which are closely related to tubulointerstitial fibrosis, and systemic inflammation. In previous studies, it has been confirmed that curcumin could alleviate tubulointerstitial fibrosis, and improve renal function through its antioxidant, anti-apoptotic, and anti-inflammatory efficacies. However, the effects curcumin exerts on intestinal flora in uric acid nephropathy are still unknown. Therefore, we used next-generation sequencing technology to investigate the effects of curcumin on gut microbiota in a rat model of UAN induced by adenine and potassium oxonate, and rats were randomly divided into control, model or curcumin treatment groups. The results demonstrated that, compared to the model group, the treatment group showed decreased serum uric acid (156.80 ± 11.90 μmol/L vs. 325.60 ± 18.65 μmol/L, p < 0.001), serum creatinine (66.20 ± 11.88 μmol/L vs. 182.20 ± 8.87 μmol/L, p < 0.001) and BUN level (13.33 ± 3.16 mmol/L vs. 36.04 ± 6.60 mmol/L, p < 0.001). The treatment group also displayed attenuated renal pathological lesions and metabolic endotoxemia (25.60 ± 5.90 ng/mL vs. 38.40 ± 4.98 ng/mL, p < 0.01), and improved tightly linked proteins expression. Besides, curcumin altered the gut microbiota structure in UAN rats. More specifically, curcumin treatment protected against the overgrowth of opportunistic pathogens in UAN, including Escherichia-Shigella and Bacteroides, and increased the relative abundance of bacteria producing short‐chain fatty acids (SCFAs), such as Lactobacillus and Ruminococcaceae. These results suggest that curcumin could modulate gut microbiota, fortify the intestinal barrier, attenuate metabolic endotoxemia, and consequently protect the renal function in UAN rats.

The Rho kinase signaling pathway participates in tubular mitochondrial oxidative injury and apoptosis in uric acid nephropathy

Introduction

Oxidative stress is a pathologic feature of hyperuricemia that is highly prevalent and that contributes to kidney tubular interstitial fibrosis. Rho-kinase is closely related to mitochondrial-induced oxidative stress. Herein, we designed a study to explore the expression and role of Rho-kinase in hyperuricemia nephropathy. The secondary objective was to investigate whether the Rho-kinase signaling pathway regulates hyperuricemic tubular oxidative injury and apoptosis via the mitochondrial pathway in addition to the mechanisms that are involved.

Materials and methods

HK-2 cells were divided into the following five groups: normal; uric acid (UA); UA+Fasudil; UA+ROCK1 si-RNA; and UA+sc-siRNA. Rho-kinase activity, mitochondrial oxidative injury, and apoptosis-related protein levels were measured in each group. A t-test was used to analyze the difference between groups.

Results

Myosin phosphatase target subunit 1 (MYPT1) overexpression was shown in HK-2 cells, which was caused by UA. High concentrations of UA also up-regulated Rho-kinase expression and mitochondrial and apoptosis-related protein expression, while treatment with fasudil and ROCK1 si-RNA significantly attenuated these responses.

Conclusion

The Rho-kinase signaling pathway participates in tubular mitochondrial oxidative injury and apoptosis via regulating mitochondrial dyneins/biogenic genes in UA nephropathy, which suggests that the mitochondrial pathway might be a potential therapeutic target for hyperuricemia nephropathy.

Synthesis, SAR study, and bioactivity evaluation of a series of Quinoline-Indole-Schiff base derivatives: Compound 10E as a new Nur77 exporter and autophagic death inducer

We previously reported 5-((8-methoxy-2-methylquinolin-4-yl)amino)-1H-indole- 2-carbohydrazide derivatives as new Nur77 modulators. In this study, we explored whether the 8-methoxy-2-methylquinoline moiety and bicyclic aromatic rings at the N'-methylene position were critical for their antitumor activity against hepatocellular carcinoma (HCC). For this purpose, a small library of 5-substituted 1H-indole-2-carbohydrazide derivatives was designed and synthesized. We found that the 8-methoxy-2-methylquinoline moiety was a fundamental structure for its biological function, while the introduction of the bicyclic aromatic ring into the N'-methylene greatly improved its anti-tumor effect. We found that the representative compound 10E had a high affinity to Nur77. The K_D values were in the low micromolar (2.25-4.10 μM), which were coincident with its IC₅₀ values against the tumor cell lines (IC₅₀ < 3.78 μM). Compound 10E could induce autophagic cell death of liver cancer cells by targeting Nur77 to mitochondria while knocking down Nur77 greatly impaired anti-tumor effect. These findings provide an insight into the structure-activity relation of Quinoline-Indole-Schiff base derivatives and further demonstrate that antitumor agents targeting Nur77 may be considered as a promising strategy for HCC therapy.

3-Methyladenine-enhanced susceptibility to sorafenib in hepatocellular carcinoma cells by inhibiting autophagy

As an effective targeted therapy for advanced hepatocellular carcinoma (HCC), sorafenib resistance has been frequently reported in recent years, with the activation of autophagy by cancer cells under drug stress being one of the crucial reasons. Sorafenib treatment could enhance autophagy in HCC cells and autophagy is also considered as an important mechanisms of drug resistance. Therefore, the inhibition of autophagy is a potential way to improve the sensitivity and eliminate drug resistance to restore their efficacy. To determine whether autophagy is involved in sorafenib resistance and investigate its role in the regulation of HepG2 cells' (an HCC cell line) chemosensitivity to sorafenib, we simultaneously treated HepG2 with sorafenib and 3-Methyladenine (3-MA) (a common autophagy inhibitor). First, by performing cell counting kit 8 cell viability assay, Hoechst 33342 apoptosis staining, and Annexin V-fluorescein isothiocyanate/propidium iodide apoptosis kit detection, we found that both sorafenib and 3-MA effectively inhibitted the proliferative activity of HepG2 cells and induced their apoptosis to a certain extent. This effect was significantly enhanced after these two drugs were combined, which was also confirmed by the increased expression of apoptosis-related proteins. Subsequently, by using AAV-GFP-LC3 transfection methods and transmission electron microscopy, we found that both the number and activity of autophagosomes in HepG2 cells in sorafenib and 3-MA group were significantly reduced, suggesting that autophagy activity was inhibited, and this result was consistent with the expression results of autophagy-related proteins. Therefore, we conclude that 3-MA may attenuate the acquired drug resistance of sorafenib by counteracting its induction of autophagy activity, thus enhancing its sensitivity to advanced HCC therapy.

FAM134B-mediated endoplasmic reticulum autophagy protects against sepsis myocardial injury in mice

Reticulophagy regulator 1 (RETEG1, also known as FAM134B) plays a crucial role in endoplasmic reticulum autophagy. We aimed to explore the effect of FAM134B-mediated endoplasmic reticulum autophagy in sepsis myocardial injury in mice. Sepsis myocardial injury mice were established via cecal ligation and puncture procedures. The expression of FAM134B and LC3-II/I was determined using immunohistochemistry. Myocardial tissue morphological changes and apoptosis were examined using hematoxylin and eosin (H&E) staining and TUNEL analysis. The effects of FAM134B knockdown or overexpression on mice with sepsis myocardial injury were also studied. The levels of TNF-α, IL-6, IL-8, and IL-10 were evaluated using enzyme-linked immunosorbent assay (ELISA). Autophagy- and apoptosis-related protein expression was detected using western blotting. The effect of FAM134B on Lipopolysaccharide (LPS) -induced cardiomyocytes was also studied. The expression of FAM134B and LC3-II/I increased in sepsis mice and lipopolysaccharide (LPS)-treated cardiomyocytes. 3-Methyladenine (3-MA) significantly inhibited FAM134B and LC3-II/I expression and promoted myocardial injury, inflammation response, and cardiomyocyte apoptosis. The overexpression of FAM134B could minimize myocardial injury, inflammation, and apoptosis, whereas FAM134B knockdown showed opposite effects. FAM134B-mediated endoplasmic reticulum autophagy had a protective effect on sepsis myocardial injury in mice by reducing inflammation and tissue apoptosis, which may provide new insights for sepsis myocardial injury therapies.

Hyperuricemia causes kidney damage by promoting autophagy and NLRP3-mediated inflammation in rats with urate oxidase deficiency

Epidemiological research has shown that elevated serum urate concentration is a risk factor for the development of kidney disease; however, the mechanisms underlying this process have not yet been elucidated. To examine the role of urate in the kidney, we used Wistar rats to functionally disrupt expression of urate oxidase (UOX) by using the CRISPR/Cas9 system. In comparison to wild-type (WT) rats, serum urate levels spontaneously and persistently increased in UOX-KO rats, without showing a significant decrease in survival rate. Architecture and function of the kidneys in UOX-KO rats were impaired. Injury to the kidney resulted in increased interstitial fibrosis, macrophage infiltration, increased expression of NLRP3 and IL-1β, and activation of multiple cell-signaling pathways associated with autophagy, such as AMPK, p38 MAPK, ERK and JNK pathways. Inhibition of autophagy with the PI3K inhibitor 3-MA abrogated the development of kidney damage and attenuated renal fibrosis, macrophage infiltration, and expression of NLRP3 and IL-1β in injured kidneys. In conclusion, the UOX-KO rat is a great model to study hyperuricemia-related diseases. Hyperuricemia-induced autophagy and NLRP3-dependent inflammation are critically involved in the development of renal damage and, therefore, highlight the inhibition of autophagy and inflammation in search of therapeutic strategies to treat uric acid nephropathy.

Autophagy, tissue repair, and fibrosis: a delicate balance

Tissue repair and fibrosis, an abnormal form of repair, occur in most human organs in response to injury or inflammation. Fibroblasts play a major role in the normal repair process by differentiating into myofibroblasts that synthesize extracellular matrix (ECM) components and favor tissue remodeling to reestablish normal function and integrity. However, their persistent accumulation at the site of injury is a hallmark of fibrosis. Autophagy is a catabolic process that occurs in eukaryotic cells as a stress response to allow cell survival and maintenance of cellular homeostasis by degrading and recycling intracellular components. Recent advances identify autophagy as an important regulator of myofibroblast differentiation, tissue remodeling, and fibrogenesis. In this mini-review, we provide an overview of the interactions between autophagy, ECM, and fibrosis, and emphasize the molecular mechanisms involved in myofibroblast differentiation. We also describe the emerging concept of secretory autophagy as a new avenue for intercellular communication at the site of tissue injury and repair.

The roles of NLRP3 inflammasome-mediated signaling pathways in hyperuricemic nephropathy

Hyperuricemic nephropathy (HN) is a common clinical complication of hyperuricemia. High-serum uric acid can trigger renal inflammation. The inflammasome family has several members and shows a significant effect on inflammatory responses. NLRP3 (NOD-, LRR-, and pyrin domain-containing 3) senses the stimuli signal of excessive uric acid and then it recruits apoptosis-related specular protein (ASC) as well as aspartic acid-specific cysteine protease (caspase)-1 precursor to form NLRP3 inflammasome. NLRP3 inflammasome is activated in acute kidney injury (AKI), chronic kidney diseases (CKD), diabetic nephropathy (DN), and HN. This review focuses on important role for the involvement of NLRP3 inflammasome and associated signaling pathways in the pathogenesis of hyperuricemia-induced renal injury and the potential therapeutic implications. Additionally, several inhibitors targeting NLRP3 inflammasome are under development, most of them for experiment. Therefore, researches into NLRP3 inflammasome modulators may provide novel therapies for HN.

Autophagy inhibition attenuates TGF-β2-induced epithelial-mesenchymal transition in lens epithelial cells

AIMS

Autophagy has been reported to play an essential role in fibrotic disorders. Known as fibrotic cataract, posterior capsular opacification (PCO) result from pathological epithelial-mesenchymal transition (EMT) of lens epithelial cells (LECs). This study aims to identify the role and potential mechanism of autophagy in TGF-β2-induced EMT in LECs.

MAIN METHODS

Primary rabbit LECs were treated with TGF-β2 to induce EMT as a model of fibrotic cataract in vitro. 3-methyladenine, chloroquine, bafilomycin A1, and gene silencing of autophagy-related protein 7 (ATG7) were treated in LECs for autophagy inhibition, while rapamycin was utilized for autophagy activation. The expression levels of EMT/autophagy-associated markers were analyzed by qRT-PCR, western blotting, immunofluorescence and transmission electron microscopy. We additionally examined cell migration ability with transwell migration assay and wound healing assay.

KEY FINDINGS

TGF-β2 promoted autophagy flux during EMT progression of LECs in a time-dependent manner. Autophagy activation by rapamycin enhanced TGF-β2-triggered fibrogenic responses and cell migration in LECs, whereas pharmacological inhibition of autophagy alleviated TGF-β2-induced increases of EMT markers and cell migration of LECs. In addition, the phosphorylation of Smad2/3 induced by TGF-β2 was suppressed through autophagy inhibition, while it was promoted upon autophagy activation, indicating that TGF-β2/Smad signaling was involved in the modulation of autophagy on EMT in LECs. Furthermore, ATG7-silenced LECs exerted anti-fibrosis effect induced by TGF-β2 through downregulation of autophagy.

SIGNIFICANCE

Intervention/inhibition of autophagy could attenuate TGF-β2-induced EMT in LECs, which provides autophagy-related insights on preventing and treating the fibrotic cataract or other fibrotic diseases.

Targeting Autophagy in Breast Cancer

Breast cancer is a heterogeneous disease consisting of different biological subtypes, with differences in terms of incidence, response to diverse treatments, risk of disease progression, and sites of metastases. In the last years, several molecular targets have emerged and new drugs, targeting PI3K/Akt/mTOR and cyclinD/CDK/pRb pathways and tumor microenvironment have been integrated into clinical practice. However, it is clear now that breast cancer is able to develop resistance to these drugs and the identification of the underlying molecular mechanisms is paramount to drive further drug development. Autophagy is a highly conserved homeostatic process that can be activated in response to antineoplastic agents as a cytoprotective mechanism. Inhibition of autophagy could enhance tumor cell death by diverse anti-cancer therapies, representing an attractive approach to control mechanisms of drug resistance. In this manuscript, we present a review of autophagy focusing on its interplay with targeted drugs used for breast cancer treatment.

Research Advances in the Mechanisms of Hyperuricemia-Induced Renal Injury

Uric acid is the end product of purine metabolism in humans, and its excessive accumulation leads to hyperuricemia and urate crystal deposition in tissues including joints and kidneys. Hyperuricemia is considered an independent risk factor for cardiovascular and renal diseases. Although the symptoms of hyperuricemia-induced renal injury have long been known, the pathophysiological molecular mechanisms are not completely understood. In this review, we focus on the research advances in the mechanisms of hyperuricemia-caused renal injury, primarily on oxidative stress, endothelial dysfunction, renal fibrosis, and inflammation. Furthermore, we discuss the progress in hyperuricemia management.

Dexmedetomidine Enhances Autophagy via α2-AR/AMPK/mTOR Pathway to Inhibit the Activation of NLRP3 Inflammasome and Subsequently Alleviates Lipopolysaccharide-Induced Acute Kidney Injury

Background

Acute kidney injury (AKI) is a severe complication of sepsis; however, no effective drugs have been found. Activation of the nucleotide-binding domain-like receptor protein 3 (NLRP3) inflammasome is a major pathogenic mechanism of AKI induced by lipopolysaccharide (LPS). Autophagy, a process of intracellular degradation related to renal homeostasis, effectively restricts inflammatory responses. Herein, we explored the potential protective mechanisms of dexmedetomidine (DEX), which has confirmed anti-inflammatory effects, on LPS-induced AKI.

Methods

AKI was induced in rats by injecting 10 mg/kg of LPS intraperitoneally (i.p.). Wistar rats received intraperitoneal injections of DEX (30 µg/kg) 30 min before an intraperitoneal injection of LPS. Atipamezole (ATI) (250 µg/kg) and 3-methyladenine (3-MA) (15 mg/kg) were intraperitoneally injected 30 min before the DEX injection.

Results

DEX significantly attenuated renal injury. Furthermore, DEX decreased activation of the NLRP3 inflammasome and expression of interleukins 1β and 18. In addition, autophagy-related protein and gene analysis indicated that DEX could significantly enhance autophagy. Finally, we verified the pharmacological effects of DEX on the 5′-adenosine monophosphate-activated protein kinase (AMPK)/mechanistic target of rapamycin (mTOR) pathway. Atip and 3-MA significantly reversed the protective effects of DEX.

Conclusions

Our results suggest that the protective effects of DEX were mediated by enhanced autophagy via the α₂-adrenoreceptor/AMPK/mTOR pathway, which decreased activation of the NLRP3 inflammasome. Above all, we verified the renal protective effects of DEX and offer a new treatment strategy for AKI.

3-Methyladenine Alleviates Experimental Subretinal Fibrosis by Inhibiting Macrophages and M2 Polarization Through the PI3K/Akt Pathway

Purpose: To explore the effects of 3-methyladenine (3-MA), a selective inhibitor of phosphatidylinositol-3-kinase (PI3K), on experimental subretinal fibrosis (SRF) in mice. Methods: The SRF mouse model was established by 532 nm laser photocoagulation at each fundus of mice on day 0. 3-MA was administered every 2 days from day 0 to 35. Immunofluorescence of choroidal flat mounts was performed to evaluate the size of SRF area, local macrophages, and polarization, respectively. Besides, Western blot analysis was carried out to assess the expression levels of macrophage polarization-related genes, Arg-1, Ym-1, and transforming growth factor-β₂ (TGF-β₂). Co-culture and migration experiments were used to demonstrate the inhibitory effect of 3-MA on fibroblasts. The gene knockout and Western blot analysis were used to explore the signal pathways related to macrophage polarization. Results: Compared with the control group, the 3-MA-treated group showed significantly less size of SRF area. 3-MA treatment reduced both circulating and local macrophages, and counteracted M2 polarization. Moreover, 3-MA inhibited fibroblast recruitment. Mechanistically, we proved that 3-MA inhibits macrophage M2 polarization by suppressing PI3K/Akt signal pathway rather than the PI3K-autophagy-related signal pathway. Conclusions: 3-MA exerts antifibrotic effects on experimental SRF by targeting circulating and local macrophages and M2 polarization, through PI3K/Akt signal pathway. These results support the potential use of 3-MA as a new therapeutic modality for SRF associated with neovascular age-related macular degeneration.

Delayed treatment with an autophagy inhibitor 3-MA alleviates the progression of hyperuricemic nephropathy

Autophagy is a cell self-renewal process that relies on the degradation of the cytoplasmic proteins or organelles of lysosomes and is associated with development of numerous diseases. However, the therapeutic effect of autophagy inhibition on hyperuricemic nephropathy (HN) and the underlying mechanisms are still unknown. Here, we investigated the effect of delayed treatment with 3-methyladenine (3-MA), a specific autophagy inhibitor, on the development of HN in a rat model. Administration of 3-MA at 21 days following after uric acid injury protected kidney from hyperuricemic-related injuries, as demonstrated by improving renal dysfunction and architecture damage, blocking Beclin-1 and LC3II/I and decreasing the number of autophagic vacuoles. Late treatment with 3-MA was also effective in attenuating renal fibrosis as evidenced by reducing ECM protein deposition, blocking epithelial-to-mesenchymal transition (EMT) and decreasing the number of renal epithelial cells arrested at the G2/M phase of cell cycle. Injury to the kidney resulted in increased expression of TGFβ receptor I, and phosphorylation of Smad3, 3-MA significantly abrogated all these responses. Moreover, inhibition of autophagy suppressed mitochondrial fission, downregulated the expression of Dynamin-related protein 1 (Drp-1), Cofilin and F-actin, and alleviated cell apoptosis. Finally, 3-MA effectively blocked STAT3 and NF-κB phosphorylation and suppressed infiltration of macrophages and lymphocytes as well as release of multiple profibrogenic cytokines/chemokines in the injured kidney. Taken together, these findings indicate that hyperuricemia-induced autophagy is critically involved in the activation of renal fibroblasts, EMT, mitochondrial fission and apoptosis of tubular epithelial cells and development of renal fibrosis. Thus, this study provides evidence for autophagy inhibitors as the treatment of HN patients.

Autophagy in kidney disease: Advances and therapeutic potential

Autophagy is a highly conserved intracellular catabolic process for the degradation of cytoplasmic components that has recently gained increasing attention for its importance in kidney diseases. It is indispensable for the maintenance of kidney homeostasis both in physiological and pathological conditions. Investigations utilizing various kidney cell-specific conditional autophagy-related gene knockouts have facilitated the advancement in understanding of the role of autophagy in the kidney. Recent findings are raising the possibility that defective autophagy exerts a critical role in different pathological conditions of the kidney. An emerging body of evidence reveals that autophagy exhibits cytoprotective functions in both glomerular and tubular compartments of the kidney, suggesting the upregulation of autophagy as an attractive therapeutic strategy. However, there is also accumulating evidence that autophagy could be deleterious, which presents a formidable challenge in developing therapeutic strategies targeting autophagy. Here, we review the recent advances in research on the role of autophagy during different pathological conditions, including acute kidney injury (AKI), focusing on sepsis, ischemia-reperfusion injury, cisplatin, and heavy metal-induced AKI. We also discuss the role of autophagy in chronic kidney disease (CKD) focusing on the pathogenesis of tubulointerstitial fibrosis, podocytopathies including focal segmental glomerulosclerosis, diabetic nephropathy, IgA nephropathy, membranous nephropathy, HIV-associated nephropathy, and polycystic kidney disease.