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Autophagy is a process of self-renewal in cells, which not only provides the necessary nutrients for cells, but also clears necrotic organelles. Autophagy disorders are closely related to diseases such as cancer. UNC-51-like kinase 1 (ULK1) is a serine/threonine protein kinase that plays a crucial role in receiving input from energy and nutrient sensors, activating autophagy to maintain cellular homeostasis under stressful conditions. In recent years, targeting ULK1 has become a highly promising strategy for cancer treatment. This review introduces the regulatory mechanism of ULK1 in autophagy through the AMPK/mTOR/ULK1 pathway and reviews the research progress of ULK1 activators and inhibitors and their applications in cancer treatment. In addition, we analyze the binding modes between ULK1 and modulators through virtual molecular docking, which will provide a reliable basis and theoretical guidance for the design and development of new therapeutic drugs targeting ULK1.
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Proteínas Quinasas Activadas por AMP , Neoplasias , Homólogo de la Proteína 1 Relacionada con la Autofagia/metabolismo , Simulación del Acoplamiento Molecular , Proteínas Quinasas Activadas por AMP/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Autofagia , Neoplasias/tratamiento farmacológicoRESUMEN
ObjectiveTo investigate the regulatory effect of Danggui Shaoyaosan on adenosine monophosphate-activated protein kinase （AMPK）/mammalian target of rapamycin （mTOR）/Unc-51-like kinase-1 （ULK1） signaling pathway in the rat model of metabolism-associated fatty liver disease （MAFLD）. MethodSixty SD rats were randomized into control， model， western medicine （polyene phosphatidylcholine capsules，0.144 g·kg-1）， and low-， medium-， and high-dose （2.44， 4.88， 9.76 g·kg-1， respectively） Danggui Shaoyaosan groups. After being fed with a high-fat diet for 8 weeks， the rats in each group were administrated with corresponding drugs for 4 weeks. At the end of drug treatment， serum and liver tissue were collected for subsequent determination of related indicators. ResultCompared with the control group， the model group showed increased contents of total cholesterol （TC）， triglyceride （TG）， low-density lipoprotein cholesterol （LDL-C） and activities of alanine aminotransferase （ALT） and aspartate aminotransferase （AST） in the serum， increased contents of TC， TG， and free fatty acids （FFAs） in the liver （P<0.01）， and decreased content of high-density lipoprotein cholesterol （HDL-C） in the serum （P<0.01）. Furthermore， the model group showed down-regulated protein levels of p-AMPK， microtubule-associated protein 1 light chain 3B （LC3B） Ⅱ， Beclin1， and ULK1 （P<0.01） and up-regulated protein levels of p-mTOR and ubiquitin-binding protein p62 in the liver （P<0.01）. The hepatic steatosis was obvious and the NAFLD activity score （NAS） and oil red O staining area increased in the model group， （P<0.05， P<0.01）. Compared with the model group， Danggui Shaoyaosan reduced the contents of TC and TG and the activities of ALT and AST in the serum， lowered the levels of TC， TG， and FFA in the liver， down-regulated the protein levels of p-mTOR and p62 （P<0.01）， elevated the serum HDL-C level， and up-regulated the protein levels of p-AMPK， LCBⅡ， Beclin1， and ULK1 in the liver （P<0.05， P<0.01）. Moreover， it alleviated hepatic steatosis and decreased the NAS and oil red O staining area （P<0.05， P<0.01）. ConclusionDanggui Shaoyaosan has therapeutic effect on MAFLD rats by regulating AMPK/mTOR/ULK1 signaling pathway to enhance autophagy.
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ObjectiveTo explore the mechanism and pathway of Gandou Fumu decoction （GDFMD） in the development of liver fibrosis in Wilson's disease （WD）. MethodFirst， 30 TX-j mice were randomly divided into the model group， high-dose， medium-dose， and low-dose GDFMD groups， and penicillamine group， with six mice in each group， and another six wild-type mice were used as the normal group. The high-dose， medium-dose， and low-dose GDFMD groups were intragastrically administered drugs of 13.92， 6.96， 3.48 g·kg-1. In the penicillamine group， 0.1 g·kg-1 of penicillamine was given by intragastric administration. The model group and the normal group were given equal volume of normal saline， once a day， for four consecutive weeks. Samples were collected four weeks after gavage， and enzyme-linked immunosorbent assay （ELISA） was used to detect type Ⅲ procollagen peptide （PCⅢ）， collagen type Ⅳ （Col Ⅳ）， hyaluronic acid （HA）， and laminin （LN）. Hematoxylin-eosin （HE）， Masson， and picric acid-Sirus red collagen （Sirus Red） staining were used to observe the histopathological changes of liver fibrosis. Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR）， immunohistochemistry， and Western blot were used to observe the expressions of α-smooth muscle actin （α-SMA） and collagen type Ⅰ （Col Ⅰ）， which were related to the activation of hepatic stellate cells （HSCs）. The expression of miR-29b-3p was observed by Real-time PCR. The expression of Unc-51-like kinase 1 （ULK1） and its downstream-related factors were observed by Western blot. The downstream genes of miR-29b-3p were verified by the dual luciferase reporter gene detection method. ResultCompared with the normal group， the four items of liver fibrosis （PCⅢ， Col Ⅳ， HA， and LN） in the model group were significantly abnormal （P<0.01）， and the pathology was significantly abnormal. The expression of HSC activation-related indicators including α-SMA and Col Ⅰ， as well as α-SMA mRNA and Col Ⅰ mRNA was up-regulated （P<0.05， P<0.01）， and miR-29b-3p expression was down-regulated （P<0.01）. ULK1， p-ULK1， autophagy-related gene 13 （Atg13）， p-Atg13， Beclin-1， FAK family kinase-interacting protein of 200 kDa （FIP200）， activating molecule in BECN1-regulated autophagy protein 1 （AMBKA1）， and microtubule-associated protein 1 light chain 3Ⅱ/Ⅰ（LC3Ⅱ/Ⅰ） were up-regulated （P<0.05， P<0.01）. p62 protein expression was down-regulated （P<0.01）. Compared with the model group， the four items of liver fibrosis in the high-dose， medium-dose， and low-dose GDFMD groups and the penicillamine group were significantly improve （P<0.01）， and the pathological conditions were improved. The expression of HSC activation-related indicators including α-SMA and Col Ⅰ， as well as α-SMA mRNA and Col Ⅰ mRNA was down-regulated （P<0.05， P<0.01）， and the expression of miR-29b-3p was up-regulated （P<0.01）. ULK1， p-ULK1， Atg13， p-Atg13， Beclin-1， FIP200， AMBKA1， and LC3Ⅱ/Ⅰ were down-regulated （P<0.05， P<0.01）， and p62 protein expression was up-regulated （P<0.01）. The prediction software predicted that there was a binding site between miR-29b-3p and ULK1. The dual-luciferase reporter gene detection method indicated that the luciferase activity of the ULK1-WT plasmid-transfected cell group was reduced when miR-29b-3p mimics were co-cultured （P<0.01）. ConclusionGDFMD can regulate ULK1-mediated autophagy by up-regulating miR-29b-3p and further exert its anti-hepatic fibrosis effect in Wilson's disease.
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ObjectiveThis study aims to examine the effect of Rhei Radix et Rhizoma-Coptidis Rhizoma on reducing insulin resistance in db/db mice by regulating the adenylate activated protein kinase （AMPK）/UNC-51-like kinase 1 （ULK1）/key molecule of autophagy， benzyl chloride 1 （Beclin1） pathway and elucidate the underlying mechanism. MethodSixty 6-week-old male db/db mice were studied. They were randomly divided into the model group， metformin group （0.26 g·kg-1）， and low-， middle-， and high-dose groups （2.25， 4.5， 9 g·kg-1） of Rhei Radix et Rhizoma-Coptidis Rhizoma. A blank group of db/m mice of the same age was set， with 12 mice in each group. After eight weeks of continuous intragastric administration， the blank group and model group received distilled water intragastrically once a day. The survival status of the mice was observed， and fasting blood glucose （FBG） was measured using a Roche blood glucose device. Fasting serum insulin （FINS） was measured using an enzyme-linked immunosorbent assay， and the insulin resistance index （HOMA-IR） was calculated. Hematoxylin-eosin （HE） staining was performed to observe the pathological changes in the liver of the mice. The protein expression levels of AMPK， Beclin1， autophagy associated protein 5 （Atg5）， and p62 in liver tissue were determined by using Western blot. The protein expression levels of autophagy associated protein 1 light chain 3B （LC3B） and ULK1 in liver tissue were determined using immunofluorescence. Real-time fluorescence quantitative PCR （Real-time PCR） was used to measure mRNA expression levels of AMPK， Beclin1， Atg5， ULK1， and p62. ResultCompared with the blank group， the model group exhibited a significant increase in body mass （P<0.01）. Additionally， the levels of FBG， FINS， and HOMA-IR significantly changed （P<0.01）. The structure of liver cells was disordered. The protein expression levels of AMPK， Beclin1， and Atg5 in liver tissue were significantly decreased （P<0.01）， while the expression level of p62 protein was significantly increased （P<0.01）. The expression levels of mRNA and proteins were consistent. Compared with the model group， the body mass of the metformin group and high and medium-dose groups of Rhei Radix et Rhizoma-Coptidis Rhizoma was significantly decreased （P<0.05）. FBG， FINS， and HOMA-IR were significantly decreased （P<0.05，P<0.01）. After treatment， the liver structure damage in each group was alleviated to varying degrees. The protein expressions of AMPK， Beclin1， Atg5， LC3B， and ULK1 were increased （P<0.05，P<0.01）， while the protein expression of p62 was decreased （P<0.01）. The expression levels of mRNA and proteins were generally consistent. ConclusionThe combination of Rhei Radix et Rhizoma-Coptidis Rhizoma can effectively improve liver insulin resistance， regulate the AMPK autophagy signaling pathway， alleviate insulin resistance in db/db mice， and effectively prevent the occurrence and development of type 2 diabetes.
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AIM: To explore the intervention effect of Dahuangtang pellets (DHT) on diabetic nephropathy (DN) based on the AMP-activated protein kinase/mammalian target of rapamycin/unc-51-like kinase 1 (AMPK/mTOR/ULK1) signaling pathway. METHODS: Eight mice were randomly assigned to the model group, the dapagliflozin group, and the DHT (high, medium, and low dosage) group out of a total of 40 C57BL/KSJ-db/db (hereafter referred to as db/db) mice; another 10 C57BL/KSJ-db/dm mice were used as the normal group, saline was provided to the normal and model groups, and the mice in the treatment group received the appropriate medications. The medications were given for 10 consecutive weeks, once per day, to the mice in the treatment group. At weeks 0, 4, 8, and 10 of administration, fasting blood glucose (FBG) was assessed by drawing blood at a predetermined time from the tail vein; Urine samples were taken at 0, 5, and 10 weeks after treatment to evaluate the levels of albumin and creatinine, and the urinary albumin-creatinine ratio (ACR) was computed. After 10 weeks, mice in each group were assayed for 24 h total urine protein, serum creatinine (Scr), urea nitrogen (BUN) levels; Western blotting analysis was conducted to detect the expression of p-AMPK, p-mTOR, and p-ULK1, as well as the expression of autophagy related proteins homolog of yeast Atg6 (Beclin-1), autophagy-related proteins microtubule-associated protein 1 light chain 3 (LC3), P62 in renal tissue; Immunohistochemistry was used to measure the expression of podocyte lacunar membrane proteins (Nephrin, Podocin) in renal tissues; The pathological morphology of renal tissue was observed by light microscopy and transmission electron microscopy. RESULTS: Compared with the model group, FBG, ACR, and 24 h total urine protein were reduced in the dapagliflozin group and DHT groups of mice, and there was no statistically significant difference in Scr and BUN; In renal tissues, there is increased expression of p-AMPK and p-ULK1, decreased expression of p-mTOR, increased expression of LC3II / LC3I and Beclin-1, and decreased expression of P62 (P<0.01, P< 0.05); differentially upregulated in glomeruli are the podocyte lacunar membrane proteins Nephrin and Podocin (P<0.01, P<0.05); renal pathologic damage was reduced to varying degrees; transmission electron microscopy showed an increase in the number of autophagic vesicles and autophagic lysosomes. CONCLUSION: DHT can delay the development of DN by regulating the AMPK / mTOR / ULK1 signaling pathway, enhancing podocyte autophagy, and protecting glomeruli.
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ObjectiveTo study the mechanism of Renshen Baidusan in regulating adenylate-activated protein kinase （AMPK）/Unc-51-like kinase 1 （ULK1） autophagy pathway to inhibit mucosal barrier damage in the mouse model of ulcerative colitis （UC）. MethodSixty SD rats were randomized into normal， model， sulfasalazine enteric-coated tablets （0.312 5 g·kg-1， western medicine）， and high-， medium-， and low-dose （31.2， 15.6， 7.8 g·kg-1， respectively） Renshen Baidusan groups. The UC model was induced by 2，4，6-trinitrobenzenesulfonic acid （TNBS）/50% ethanol. The drugs were administrated by gavage for 2 weeks， and then the histopathological changes of the colon were examined. Real-time quantitative polymerase chain reaction was conducted to measure the mRNA level of AMP-activated protein kinase subunit alpha （AMPKα）. Western blot was employed to determine the protein levels of closure protein （Occludin）， compact linking protein-2 （Claudin-2）， autophagy marker p62， microtubule-associated protein 1 light chain 3B （LC3B）， phosphorylated AMPK （p-AMPK）， and phosphorylated ULK1 （p-ULK1）. ResultCompared with the normal group， the model group showed increased colon injury score （P<0.05）， down-regulated mRNA level of AMPKα （P<0.05） and protein levels of p-AMPK， p-ULK1， and Occludin， decreased LC3Ⅱ/Ⅰ ratio （P<0.05）， and up-regulated protein levels of p62 and Claudin-2 （P<0.05）. Compared with the model group， all the doses of Renshen Baidusan lowered the colon injury score， up-regulated the mRNA level of AMPKα and the protein levels of p-AMPK， p-ULK1， and Occluding， increased LC3Ⅱ/Ⅰ ratio， and down-regulated the protein levels of p62 and Claudin-2. Moreover， the medium-dose group showed a significant intervention effect （P<0.05）. ConclusionRenshen Baidusan can protect the intestinal mucosal barrier from damage， and the medium dose showed the best efficacy. It may activate the AMPK/ULK1 pathway to accelerate the transformation of LC3Ⅰ to LC3Ⅱ and promote the degradation of p62， so as to improve the function of Occludin and Claudin-2 and repair the mechanical damage of the intestinal barrier.
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Objective:To investigate the effects of fluoride exposure on autophagy and the expression levels of adenosine monophosphate activated protein kinase (AMPK), mammalian target of rapamycin (mTOR) and Unc-51-like kinase 1 (ULK1) in mouse neuroblastoma and rat glioma fusion cells (NG108-15 cells).Methods:NG108-15 cells were cultured in vitro and divided into control group (0 mg/L), low fluoride group (20 mg/L), medium fluoride group (40 mg/L) and high fluoride group (80 mg/L) according to the final concentration of sodium fluoride, and the cells were collected after 24 h of treatment for standby. NG108-15 cells autophagy was detected by immunofluorescence/immunocytochemistry (IF/ICC method, the autophagy positive control group was treated with chloroquine phosphate); the mRNA expression levels of AMPK, mTOR and ULK1 in each group were detected by real-time fluorescent quantitative polymerase chain reaction (qRT-PCR); the protein expression levels of autophagy related protein microtubule-associated protein 1 light chain 3B (LC3B), AMPK, mTOR, ULK1, phosphorylation (p)-AMPK, p-mTOR, p-ULK1 in each group were detected by Western blotting. Results:No autophagosome was detected in the control group, and autophagosomes were detected in all the fluoride groups. The protein expression level of LC3B in the low, medium and high fluoride groups (1.80 ± 0.59, 2.16 ± 0.60, 2.30 ± 0.57) was significantly higher than that in the control group (1.00 ± 0.29, P < 0.05). The results of qRT-PCR showed that compared with the control group, the mRNA expression levels of AMPK in medium and high fluoride groups were higher (2.30 ± 0.57, 4.41 ± 1.05 vs 1.00 ± 0.01, P < 0.05); the mRNA expression levels of mTOR in the low, medium and high fluoride groups were lower (0.79 ± 0.04, 0.76 ± 0.09, 0.64 ± 0.10 vs 1.00 ± 0.01, P < 0.05), and the mRNA expression levels of ULK1 were higher (1.81 ± 0.39, 1.96 ± 0.35, 4.22 ± 1.03 vs 1.00 ± 0.01, P < 0.05). The results of Western blotting showed that compared with the control group, the protein expression levels of AMPK (1.21 ± 0.05, 1.20 ± 0.04, 1.30 ± 0.07 vs 1.00 ± 0.03), p-AMPK (1.12 ± 0.05, 1.20 ± 0.06, 1.49 ± 0.07 vs 1.00 ± 0.02), ULK1 (1.16 ± 0.05, 1.26 ± 0.05, 1.15 ± 0.05 vs 1.00 ± 0.04) and p-ULK1 (1.19 ± 0.04, 1.17 ± 0.02, 1.24 ± 0.05 vs 1.00 ± 0.05) in the low, medium and high fluoride groups were higher ( P < 0.05), and the protein expression levels of mTOR were lower (0.77 ± 0.03, 0.60 ± 0.03, 0.55 ± 0.04 vs 1.00 ± 0.04, P < 0.05); the protein expression levels of p-mTOR in the medium and high fluoride groups were lower (0.93 ± 0.05, 0.48 ± 0.02 vs 1.00 ± 0.02, P < 0.05). Conclusion:Fluoride exposure can induce autophagy in NG108-15 cells, and the expression of AMPK and ULK1 are up-regulated, while the expression of mTOR is down-regulated.
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ObjectiveTo explore the mechanism of Dihuang Yinzi （DHYZ）in improving astrocyte injury in the brain and regulating energy metabolism and autophagy disorder in Alzheimer's disease （AD） model mice. MethodForty male APP/PS1 transgenic mice aged four months were randomly divided into a model group and a model + DHYZ group （2.5 g·kg-1）， with 20 mice in each group. Forty C57BL/6J mice with the same background and same age were randomly divided into a control group and a control + DHYZ group （2.5 g·kg-1）， with 20 mice in each group. The mice in the control group and the model group were administered with an equal volume of sterilized normal saline by gavage， once a day for 150 days. Novel object recognition test and step-down test were performed to evaluate the learning and memory ability of mice. The expression of glial fibrillary acidic protein （GFAP） in astrocytes was detected by immunofluorescence and Western blot. High-performance liquid chromatography （HPLC） was used to detect adenosine triphosphate （ATP）， adenosine diphosphate （ADP）， and adenosine monophosphate （AMP） in brain tissues of mice， and the data obtained were used to calculate energy charge （EC） levels. The phosphorylation levels of liver kinase B1 （LKB1）， adenosine 5′-monophosphate （AMP）-activated protein kinase （AMPK）， UNC-51-like kinase 1 （ULK1）， and mammalian target of rapamycin （mTOR） and the expression levels of autophagy-related proteins Beclin-1， microtuble-associated protein 1 light chain 3 （LC3）-Ⅱ/LC3-Ⅰ， and p62 in mouse brain were measured by Western blot. ResultCompared with the control group， the model group showed decreased novel object recognition index， shortened retention latency， increased error times in the step-down test， up-regulated protein expression of GFAP， decreased content of ATP， ADP， and EC in brain tissues， elevated AMP ， increased levels of p-AMPK， p-LKB1， and p-mTOR， and protein expression of p62 ， and down-regulated p-ULK1 level and protein expression of Beclin-1 and LC3-Ⅱ/LC3-Ⅰ（P<0.01）， while the above experimental indexes were not significantly different in the control + DHYZ group. Compared with the model group， the model + DHYZ group showed increased novel object recognition index（P<0.05）， prolonged retention latency（P<0.01）， decreased error times（P<0.01） in the step-down test， reduced protein expression of GFAP（P<0.05）， increased content of ATP， ADP， and EC in brain tissues （P<0.05， P<0.01）， decreased AMP content（P<0.05）， reduced p-AMPK， p-LKB1， and p-mTOR levels and protein expression of p62， and up-regulated p-ULK1 level and protein expression of Beclin-1 and LC3-Ⅱ/LC3-Ⅰ（P<0.01）. ConclusionBy protecting astrocytes， DHYZ can improve energy metabolism and autophagy disorder in AD mice to improve the learning and memory ability of model mice.
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UNC-51-like kinase 1 (ULK1), as a serine/threonine kinase, is an autophagic initiator in mammals and a homologous protein of autophagy related protein (Atg) 1 in yeast and of UNC-51 in Caenorhabditis elegans. ULK1 is well-known for autophagy activation, which is evolutionarily conserved in protein transport and indispensable to maintain cell homeostasis. As the direct target of energy and nutrition-sensing kinase, ULK1 may contribute to the distribution and utilization of cellular resources in response to metabolism and is closely associated with multiple pathophysiological processes. Moreover, ULK1 has been widely reported to play a crucial role in human diseases, including cancer, neurodegenerative diseases, cardiovascular disease, and infections, and subsequently targeted small-molecule inhibitors or activators are also demonstrated. Interestingly, the non-autophagy function of ULK1 has been emerging, indicating that non-autophagy-relevant ULK1 signaling network is also linked with diseases under some specific contexts. Therefore, in this review, we summarized the structure and functions of ULK1 as an autophagic initiator, with a focus on some new approaches, and further elucidated the key roles of ULK1 in autophagy and non-autophagy. Additionally, we also discussed the relationships between ULK1 and human diseases, as well as illustrated a rapid progress for better understanding of the discovery of more candidate small-molecule drugs targeting ULK1, which will provide a clue on novel ULK1-targeted therapeutics in the future.
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Regulatory T (Treg) cells play an instrumental role in coordinating immune homeostasis via potent inhibitory effects. Defects in Treg cells lead to autoimmunity, but an overwhelming proportion of Treg cells encourages cancer progression. Hence, targeting Treg cells has emerged as a promising approach for mitigating disease severity. Recent studies have revealed that kinases are a critical component for tuning the fate of Treg cells, but the entire network of Treg-modulating kinases is still unclear. Here, we propose that the autophagy-activating UNC-51-like kinase 1 (ULK1) is a candidate for Treg cell modulation. While accumulating evidence has highlighted the role of autophagy-related kinases in Treg cells, the ULK1-Treg cell axis is yet to be examined. In this review, we predicted the potential role of ULK1 in Treg cell modulation. Furthermore, we summarized current ULK1 activators and inhibitors that can be investigated as Treg-targeting strategies, which might have beneficial outcomes in autoimmunity and cancer.
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Neoplasias , Linfocitos T Reguladores , Humanos , Homólogo de la Proteína 1 Relacionada con la Autofagia , Autofagia , Neoplasias/tratamiento farmacológico , Péptidos y Proteínas de Señalización IntracelularRESUMEN
DNA damage response (DDR) is a highly conserved genome surveillance mechanism that preserves cell viability in the presence of chemotherapeutic drugs. Hence, small molecules that inhibit DDR are expected to enhance the anti-cancer effect of chemotherapy. Through a recent chemical library screen, we identified shikonin as an inhibitor that strongly suppressed DDR activated by various chemotherapeutic drugs in cancer cell lines derived from different origins. Mechanistically, shikonin inhibited the activation of ataxia telangiectasia mutated (ATM), and to a lesser degree ATM and RAD3-related (ATR), two master upstream regulators of the DDR signal, through inducing degradation of ATM and ATR-interacting protein (ATRIP), an obligate associating protein of ATR, respectively. As a result of DDR inhibition, shikonin enhanced the anti-cancer effect of chemotherapeutic drugs in both cell cultures and in mouse models. While degradation of ATRIP is proteasome dependent, that of ATM depends on caspase- and lysosome-, but not proteasome. Overexpression of ATM significantly mitigated DDR inhibition and cell death induced by shikonin and chemotherapeutic drugs. These novel findings reveal shikonin as a pan DDR inhibitor and identify ATM as a primary factor in determining the chemo sensitizing effect of shikonin. Our data may facilitate the development of shikonin and its derivatives as potential chemotherapy sensitizers through inducing ATM degradation.
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ObjectiveTo explore the mechanism of Qihuang Yiqi Shexue prescription （QHYQSX） in the treatment of immune thrombocytopenia （ITP） model mice based on the autophagy mediated by the adenosine monophosphate-activated protein kinase （AMPK）/mammalian target of rapamycin （mTOR）/Unc-51-like kinase 1 （ULK1） signaling pathway. MethodFifty BALB/c mice were randomly divided into normal group， model group， high- and low-dose QHYQSX groups， and prednisone group， with 10 mice in each group. The ITP model was induced by intraperitoneal injection of anti-platelet serum （APS） of guinea pig. On the 8th day of the APS injection， drugs were administered by gavage for 14 days. Peripheral blood platelet （PLT） count and hemoglobin （Hb） concentration were detected. Spleen and thymus were separated， weighed， and the organ index was calculated. Sternum was sampled for bone marrow smear， and bone marrow megakaryocytes were classified under a microscope. Thrombopoietin （TPO）， interleukin-6 （IL-6）， IL-10， tumor necrosis factor-α （TNF-α）， transforming growth factor-β1 （TGF-β1）， and interferon-γ （IFN-γ） in the serum were detected by enzyme-linked immunosorbent assay（ELISA）. AMPK， mTOR， ULK1， microtubule-associated protein light chain 3 （LC3）， Beclin1， and p62 mRNA expression levels in the spleen were detected by Real-time fluorescence-based quantitative polymerase chain reaction （Real-time PCR）. The protein expression of AMPK， p-AMPK， p-mTOR， p-ULK1， LC3Ⅱ/LC3Ⅰ， Beclin1， and p62 in the spleen was detected by Western blot. ResultCompared with the normal group， the model group showed reduced peripheral blood PLT count， Hb， and TPO levels （P<0.05，P<0.01）， increased spleen and thymus indexes （P<0.01）， decreased number of bone marrow megakaryocytes （P<0.01）， elevated serum levels of IL-6， TNF-α， and IFN-γ （P<0.01）， and reduced IL-10 and TGF-β1 levels （P<0.01）. Compared with the model group， the groups with drug intervention showed increased PLT counts and TPO levels （P<0.01）， decreased spleen and thymus indexes （P<0.05， P<0.01）， elevated number of bone marrow megakaryocytes （P<0.05， P<0.01）， reduced serum levels of IL-6， TNF-α， and IFN-γ （P<0.05， P<0.01）， and up-regulated IL-10 and TGF-β1 levels （P<0.05，P<0.01）. Compared with the low-dose QHYQSX group， the high-dose QHYQSX group and the prednisone group showed different degrees of significant differences in improving PLT counts and levels of cellular inflammatory factors （P<0.05， P<0.01）. Real-time PCR and Western blot results showed that compared with the normal group， the model group showed up-regulated mRNA expression of AMPK， LC3， and Beclin1 and protein expression of p-AMPK/AMPK， LC3Ⅱ/LC3Ⅰ， and Beclin1 in the spleen （P<0.05， P<0.01）， and down-regulated mRNA expression of mTOR， ULK1， and p62 and protein expression of p-mTOR， p-ULK1， and p62 （P<0.05， P<0.01）. Compared with the results in the model group， high- and low-dose QHYQSX and prednisone could down-regulate the mRNA expression of AMPK， LC3， and Beclin1 and protein expression of p-AMPK/AMPK， LC3Ⅱ/LC3Ⅰ， and Beclin1 in the spleen （P<0.05， P<0.01）， and up-regulate the mRNA expression of mTOR， ULK1， and p62 and protein expression of p-mTOR， p-ULK1， and p62 （P<0.05， P<0.01）. ConclusionQHYQSX may inhibit excessive autophagy by regulating the AMPK/mTOR/ULK1 signaling pathway， thereby regulating immune intolerance and playing a role in the treatment of ITP.
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ObjectiveTo explore the effect and mechanism of Zuogui Jiangtang Tongmai prescription （ZGJTTMP） on astrocytes （ASs） injured by advanced glycation end products（AGEs） combined with oxygen-glucose deprivation （OGD）. MethodCell counting kit-8 （CCK-8） was used to determine the optimal concentration of AGEs and the action time of OGD， and the optimal blood concentration of ZGJTTMP was selected for follow-up experiments. ASs were divided into normal group， model group （AGEs + OGD）， ZGJTTMP group， an adenosine 5'-monophosphate-activated protein kinase （AMPK） inhibitor （Compound C） group， AMPK activator （AICAR） group， and combination group （ZGJTTMP + AICAR）. The morphological changes in ASs in each group were observed under an inverted microscope. The cell survival rate in each group was detected by CCK-8. The content of interleukin-1β（IL-1β）， interleukin-6（IL-6）， and tumor necrosis factor-α（TNF-α） was detected by enzyme-linked immunosorbent assay （ELISA）. The number of autophagosomes in each group was counted under an electron microscope. The expression of microtubule-associated protein light chain 3 （LC3） was observed by immunofluorescence. The protein expression of LC3， p62， p-AMPK， AMPK， p-mammalian target of rapamycin （mTOR）， mTOR， p-UNC-51 like kinase 1 （ULK1）， and ULK1 was detected by Western blot. ResultAccording to the results of cell survival rate， 200 mg·L-1 AGEs and OGD for 6 h were selected as the optimal modeling conditions for the model group， and 5% was selected as the optimal blood concentration of ZGJTTMP. Under the inverted microscope， the cells were severely damaged after modeling， but the cell injury in the ZGJTTMP group and the Compound C group was significantly improved. As revealed by ELISA results， the content of IL-1β， IL-6， and TNF-α in the model group increased （P<0.01）， and the content of inflammatory factors in the ZGJTTMP group and the Compound C group decreased （P<0.01）. Under the electron microscope， the number of autophagosomes in the model group increased significantly. The immunofluorescence results showed that the expression area of LC3 increased in the model group （P<0.01）， and the ZGJTTMP group and the Compound C group showed decreased number of autophagosomes and reduced expression area of LC3 （P<0.01）. As demonstrated by the results of Western blot， compared with the normal group， the model group showed increased expression of LC3Ⅱ/LC3Ⅰ and p-AMPK/AMPK （P<0.01） and decreased p62， p-mTOR/mTOR， and p-ULK1/ULK1 （P<0.01）. Compared with the model group， the ZGJTTMP group and the Compound C group showed decreased expression of LC3Ⅱ/LC3Ⅰ and p-AMPK/AMPK （P<0.01） and increased p62， p-mTOR/mTOR， and p-ULK1/ULK1 （P<0.01）. ConclusionZGJTTMP possesses a protective effect on ASs with inflammatory injury by AGEs combined with OGD， which may be achieved by inhibiting the activation of the AMPK/mTOR/ULK1 pathway related to autophagy， thus inhibiting the overexpression of autophagy.
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Parkinson's disease (PD), known as one of the most universal neurodegenerative diseases, is a serious threat to the health of the elderly. The current treatment has been demonstrated to relieve symptoms, and the discovery of new small-molecule compounds has been regarded as a promising strategy. Of note, the homeostasis of the autolysosome pathway (ALP) is closely associated with PD, and impaired autophagy may cause the death of neurons and thereby accelerating the progress of PD. Thus, pharmacological targeting autophagy with small-molecule compounds has been drawn a rising attention so far. In this review, we focus on summarizing several autophagy-associated targets, such as AMPK, mTORC1, ULK1, IMPase, LRRK2, beclin-1, TFEB, GCase, ERRα, C-Abelson, and as well as their relevant small-molecule compounds in PD models, which will shed light on a clue on exploiting more potential targeted small-molecule drugs tracking PD treatment in the near future.
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Autophagy is a critical cytoprotective mechanism against stress, which is initiated by the protein kinase Unc-51-like kinase 1 (ULK1) complex. Autophagy plays a role in both inhibiting the progression of diseases and facilitating pathogenesis, so it is critical to elucidate the mechanisms regulating individual components of the autophagy machinery under various conditions. Here, we examined whether ULK1 complex component autophagy-related protein 101 (ATG101) is downregulated via ubiquitination, and whether this in turn suppresses autophagy activity in cancer cells. Knockout of ATG101 in cancer cells using CRISPR resulted in severe growth retardation and lower survival under nutrient starvation. Transfection of mutant ATG101 revealed that the C-terminal region is a key domain of ubiquitination, while co-immunoprecipitation and knockdown experiments revealed that HECT, UBA and WWE domain containing E3 ubiquitin protein ligase 1(HUWE1) is a major E3 ubiquitin ligase targeting ATG101. Protein levels of ATG101 was more stable and the related-autophagy activity was higher in HUWE1-depleted cancer cells compared to wild type (WT) controls, indicating that HUWE1-mediated ubiquitination promotes ATG101 degradation. Moreover, enhanced autophagy in HUWE1-depleted cancer cells was reversed by siRNA-mediated ATG101 knockdown. Stable ATG101 level in HUWE1-depleted cells was a strong driver of autophagosome formation similar to upregulation of the known HUWE1 substrate WD repeat domain, phosphoinositide interacting 2 (WIPI2). Cellular survival rates were higher in HUWE1-knockdown cancer cells compared to controls, while concomitant siRNA-mediated ATG101 knockdown tends to increase apoptosis rate. Collectively, these results suggest that HUWE1 normally serves to suppress autophagy by ubiquitinating and triggering degradation of ATG101 and WIPI2, which in turn represses the survival of cancer cells. Accordingly, ATG101-mediated autophagy may play a critical role in overcoming metabolic stress, thereby contributing to the growth, survival, and treatment resistance of certain cancers.
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Proteínas Relacionadas con la Autofagia/metabolismo , Autofagia , Neoplasias/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Ubiquitinación , Proteínas de Transporte Vesicular/metabolismo , Proteínas Relacionadas con la Autofagia/genética , Supervivencia Celular , Células HEK293 , Células HeLa , Humanos , Proteínas de la Membrana/metabolismo , Proteínas de Unión a Fosfato/metabolismo , Proteínas de Transporte Vesicular/genéticaRESUMEN
Autophagy and glycolysis are two catabolic processes that manipulate pancreatic ductal adenocarcinoma (PDAC) development in response to hypoxia sensing, yet the underlying mechanism of how they are interlinked remain elusive. Methods: The functional roles of Unc-51 like kinase 1 and 2 (ULK1/2) in pyruvate kinase M2 (PKM2) transcription and glycolysis under hypoxia were assessed by chromatin immunoprecipitation, luciferase reporter, glucose consumption and lactate production assay. Co-immunoprecipitation, cellular ubiquitination, His-pulldown, in vitro protein kinase assay, immunofluorescence, immunohistochemistry, CRISPR technology, in silico studies were adopted to determine the molecular mechanism. Correlation analyses were performed in KPC (Pdx1-Cre; LSL-KrasG12D/+; Trp53fl/+) mice and clinical samples from PDAC patients. Therapeutic potential of ULK1/2 inhibitor and 2-deoxyglucose (2-DG) or 3-bromopyruvate (3-BP) was evaluated in cell-derived xenograft (CDX) and the patient-derived xenograft (PDX) models of nude mice. Results: ULK1/2, but not ULK3, augments hypoxic glycolysis in PDAC cells mediated by PKM2 independent of BCL2/adenovirus E1B 19 kDa interacting protein 3 (BNIP3). Mechanistically, hypoxia stimulates ULK1 to translocate into nucleus, where it interacts with and phosphorylates yes-associated protein (YAP) at Ser227, resulting in YAP stabilization through blockade of ubiquitin-proteasome system (UPS), which in turn facilitates PKM2 transcription, glycolysis, cell proliferation in vitro as well as PDAC growth in mice. ULK1/2 is positively correlated with YAP and PKM2 in tumor tissues from KPC mice and clinical samples from PDAC patients. Pharmacological deactivation of ULK1/2 potentiates the antineoplastic efficacy of 2-DG and 3-BP in CDX and PDX models. Conclusion: Our findings underscore the Ser227 autophosphorylation-dependent nuclear YAP stabilization as a central node that couples ULK1/2-initiated autophagy to hypoxic glycolysis during PDAC development and propose that targeting ULK1/2 combined with 2-DG or 3-BP might be a feasible therapeutic strategy against PDAC.
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Homólogo de la Proteína 1 Relacionada con la Autofagia/metabolismo , Carcinoma Ductal Pancreático/metabolismo , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Neoplasias Pancreáticas/metabolismo , Proteínas Señalizadoras YAP/metabolismo , Animales , Homólogo de la Proteína 1 Relacionada con la Autofagia/genética , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/patología , Línea Celular Tumoral , Proliferación Celular , Simulación por Computador , Regulación Neoplásica de la Expresión Génica , Glucólisis , Humanos , Péptidos y Proteínas de Señalización Intracelular/genética , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patología , Fosforilación , Transducción de Señal , Hipoxia Tumoral , Ensayos Antitumor por Modelo de Xenoinjerto , Proteínas Señalizadoras YAP/genética , Neoplasias PancreáticasRESUMEN
Nucleophosmin (NPM1) mutations are the most frequent genetic alteration in acute myeloid leukemia (AML) and aberrant cytoplasm-dislocated NPM1 mutant is a distinct biological characterization of this disease. Our group previously reported that NPM1 mutant elevated autophagy activity and autophagy activation contributed to leukemic cell survival. However, the molecular mechanisms by which cytoplasmic NPM1 mutant involving in the autophagy pathway has not been fully elucidated. Here, we showed that Unc-51-like kinase 1 (ULK1) as a core autophagy protein was highly expressed in NPM1-mA positive OCI-AML3 cells and primary NPM1-mutated AML blasts. Meanwhile, we found that NPM1-mA could interact with ULK1 protein and positively regulated ULK1 protein levels. Mechanically, NPM1-mA promoted TRAF6-dependent K63 ubiquitination and further maintained ULK1 stability and kinase activity via miR-146a. In addition, ULK1 high expression-mediated autophagy activation and facilitated to leukemic cell proliferation. Finally, we demonstrated that restoring ULK1 expression, ULK1 inhibitor SBI-0206965 treatment and using shULK1 partially rescued the effect of NPM1-mA on autophagy and cell survival. In conclusion, our findings suggest that NPM1 mutant interacts with ULK1, and thus, maintains its protein stability, which is required for NPM1 mutant-mediated autophagic cell survival. These data extend our understanding of the functions of NPM1 mutant in the regulation of autophagy activation in NPM1-mutated AML.
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Homólogo de la Proteína 1 Relacionada con la Autofagia/metabolismo , Autofagia , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Leucemia Mieloide Aguda/metabolismo , Proteínas Nucleares/metabolismo , Homólogo de la Proteína 1 Relacionada con la Autofagia/antagonistas & inhibidores , Benzamidas/farmacología , Línea Celular Tumoral , Proliferación Celular , Supervivencia Celular , Estabilidad de Enzimas , Células HEK293 , Humanos , Péptidos y Proteínas de Señalización Intracelular/antagonistas & inhibidores , MicroARNs/genética , MicroARNs/metabolismo , Mutación , Proteínas Nucleares/genética , Nucleofosmina , Inhibidores de Proteínas Quinasas/farmacología , Pirimidinas/farmacología , UbiquitinaciónRESUMEN
Objective:To observe the effects of Yishen Tongluo prescription （YTP） on autophagy-related proteins in rats with membranous nephropathy （MN） and explore its possible molecular mechanism in protecting the kidney. Method:Twenty of 80 Sprague-Dawley （SD） rats were randomly selected as the normal control， and the rest rats were pre-immunized and injected with cationized bovine serum albumin （C-BSA） through the tail vein to induce MN. The SD rats that were successfully modeled were randomized into the model group， benazepril hydrochloride group （10 mg·kg<sup>-1</sup>）， and low- （6.61g·kg<sup>-1</sup>）， medium- （13.22 g·kg<sup>-1</sup>）， and high-dose （26.44 g·kg<sup>-1</sup>） YTP groups， and administered with the corresponding drugs by gavage， once a day， for four consecutive weeks. Then the changes in such quantitative indicators as plasma albumin （ALB）， triglyceride （TG）， total cholesterol （TC）， serum creatinine （SCr）， blood urea nitrogen （BUN）， and 24-hour urinary total protein （UTP） were detected， followed by hematoxylin and eosin （HE） staining， Masson's trichrome staining， and periodic Schiff-methenamine （PASM） staining for observing the pathological changes in kidney under the transmission electron microscope （TEM）. The deposition of immunoglobulin G （IgG） and complement 3 （C3） in the glomerulus was detected by fluorescence immunoassay. The expression levels of autophagy marker proteins Beclin-1， microtubule-associated protein light chain 3Ⅱ （LC3Ⅱ）， and p62 were measured by immunohistochemistry （IHC）， and those of related proteins in the adenosine monophosphate-activated protein kinase / mechanisic target of rapamycin/Unc-51-like kinase 1 （AMPK/mTOR/ULK1） signaling pathway were determined by Western blot assy. Result:Compared with the normal group， the model group exhibited significantly increased UTP （<italic>P</italic><0.01） and serum TG and TC （<italic>P</italic><0.01）， decreased ALB （<italic>P</italic><0.01）， disordered glomerular structure， enlarged volume， thickened basement membrane， vacuolated renal tubules， excessively deposited collagen fibers and fuchsinophilic proteins， extensively fused podocyte foot processes， and diffusely deposited IgG and C3 in glomerular capillary loops. Besides， the expression levels of Beclin-1， LC3II， and phosphorylated AMPK （p-AMPK） decreased （<italic>P</italic><0.01）， while those of p62， phosphorylated mTOR （p-mTOR）， and phosphorylated ULK1 （p-ULK1） increased （<italic>P</italic><0.01）. The comparison with the model group revealed that the TG， TC， and UTP levels in the low-， medium-， and high-dose YTP groups and the benazepril hydrochloride group were reduced to varying degrees （<italic>P</italic><0.05， <italic>P</italic><0.01）， whereas the ALB level was increased （<italic>P</italic><0.01）. There was no statistically significant difference in SCr or BUN level. The pathological damages were alleviated. The expression levels of Beclin-1， LC3Ⅱ， and p-AMPK were up-regulated （<italic>P</italic><0.05， <italic>P</italic><0.01）， while those of p62， p-mTOR， and p-ULK1 were down-regulated （<italic>P</italic><0.05， <italic>P</italic><0.01）. Conclusion:YTP protects the kidney of rats with MN possibly by regulating related proteins in the AMPK/mTOR/ULK1 signaling pathway and activating the autophagy.
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Background A prominent feature of endemic arsenic poisoning is severe liver damage. Studies have found that liver injury is closely related to oxidative stress, lysosomes, and autophagy. Objective Through establishing a liver injury model of rats by sodium arsenite (NaAsO2)administration in drinking water, this experiment is designed to explore the roles of oxidative stress, lysosomes, and AMP activated protein kinase (AMPK)/Unc-51 like kinase 1 (ULK1) pathway in this model. Methods Twenty-four Wistar rats were randomly divided into four groups with six rats in each group (half male and half female), including control group and 25, 50, 100 mg·L−1 NaAsO2 groups. A rat liver injury model was established by drinking water containing NaAsO2 freely for 24 weeks. Then liver of rats was dissected after sacrificed, and the levels of alanine aminotransferase (ALT), alkaline phosphatase (ALP), and total bile acid (TBA), catalase (CAT), lipid peroxidation (LPO), and total antioxidant capacity (T-AOC) in liver tissues were detected by assay kits. The levels of lysosomal-associated membrane protein 2 (LAMP2), cathepsin B (CTSB), and acid phosphatase (ACP2) were determined by enzyme linked immunosorbent assay. The mRNA transcriptional expressions of AMPK, ULK1, microtubule-associated protein light chain 3 (LC3), and sequestosome 1 (p62) were detected by real-time fluorescence quantitative PCR (RT-qPCR). The protein expressions of p-AMPK, p-ULK1, LC3, and p62 were detected by immunohistochemistry. Results Following the NaAsO2 administration, significant differences were found in the levels of ALT, ALP, and TBA among the designed groups (F=12.09, 72.11, and 23.58, P<0.05). Compared with the control group, the levels of ALT in the 50mg·L−1 and 100 mg·L−1 NaAsO2 groups were increased (P<0.05); the levels of ALP and TBA in the 25, 50, and 100 mg·L−1 NaAsO2 groups were increased (P<0.05); the level of LPO in the 100 mg·L−1 group was increased (P<0.05); the levels of CAT and T-AOC in the 25, 50, and 100 mg·L−1 NaAsO2 groups were decreased (P<0.05). According to the results of enzyme linked immunosorbent assay, the levels of ACP2 in the 25, 50, and 100 mg·L−1 NaAsO2 groups, the level of CTSB in the 100 mg·L−1 NaAsO2 group, and the levels of LAMP2 in the 50 and 100 mg·L−1 NaAsO2 groups were decreased compared with the control group (P<0.05). Based on the results of RT-qPCR and immunohistochemistry, the mRNA transcriptional and protein expressions of AMPK, ULK1, and LC3 in some arsenic groups were elevated to varying degrees compared with the control group, and the increment in the 100 mg·L−1 NaAsO2 group was significant for all the indicators (P<0.05); the mRNA transcriptional expressions of p62 in the three arsenic groups and the protein expressions of p62 in the 50 and 100mg·L−1 NaAsO2 groups also increased compared with the control group (P<0.05). Besides, the results of Pearson correlation analysis showed that there was a positive correlation of T-AOC with LAMP2, CTSB, and ACP2 (r=0.651, 0.673, 0.626; P<0.05), a negative correlation of LPO with CTSB and ACP2 (r=−0468, −0.482; P<0.05), a negative correlation of p62 with LAMP2, CTSB, and ACP2 (r=−0.57, −0.626, −0.591; P<0.05), and a positive correlation of p62 with ALT, ALP, and TBA (r=0.709, 0.897, and 0.857, P<0.05). Conclusion Long-term arsenic exposure may induce oxidative stress, damage lysosomes, and activate the AMPK/ULK1 pathway, which can lead to the blockage of autophagy process, and eventually result in liver damage.
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Sepsis-associated encephalopathy (SAE) has typically been associated with a poor prognosis. Although sestrin 2 (SESN2) plays a crucial role in metabolic regulation and the stress response, its expression and functional roles in SAE are still unclear. In the present study, SAE was established in mice through caecal ligation and puncture (CLP). The adeno-associated virus 2 (AAV2)-mediated SESN2 expression (ie overexpression and knockdown) system was injected into the hippocampi of mice with SAE, and subsequently followed by electron microscopic analysis, the Morris water maze task and pathological examination. Our results demonstrated an increase of SESN2 in the hippocampal neurons of mice with SAE, 2-16 hours following CLP. AAV2-mediated ectopic expression of SESN2 attenuated brain damage and loss of learning and memory functions in mice with SAE, and these effects were associated with lower pro-inflammatory cytokines in the hippocampus. Mechanistically, SESN2 promoted unc-51-like kinase 1 (ULK1)-dependent autophagy in hippocampal neurons through the activation of the AMPK/mTOR signalling pathway. Finally, AMPK inhibition by SBI-0206965 blocked SESN2-mediated attenuation of SAE in mice. In conclusion, our findings demonstrated that SESN2 might be a novel pharmacological intervention strategy for SAE treatment through promotion of ULK1-dependent autophagy in hippocampal neurons.