Astragaloside-IV promotes autophagy via the Akt/mTOR pathway to improve cellular lipid deposition.

The current study aimed to investigate the potential role of astragaloside IV (AS-IV) in improving cellular lipid deposition and its underlying mechanism. A fatty liver cell model was established by treating hepatoma cells with palmitic acid. AS-IV and SC79 were used for treatment. Oil Red O staining was applied to detect intracellular lipid deposition, and transmission electron microscopy was utilized to assess autophagosome formation. Immunofluorescence double staining was applied to determine microtubule-associated proteins 1A/1B light chain 3 (LC3) expression. Western blot analysis was performed to detect the expression of LC3, prostacyclin, Beclin-1, V-akt murine thymoma viral oncogene homolog (Akt), phosphorylated Akt, mTOR, and phosphorylated mTOR. Oil Red O staining revealed that AS-IV reduced intracellular lipid accumulation. Further, it increased autophagosome synthesis and the expression of autophagy proteins LC3 and Beclin-1 in the cells. It also reduced the phosphorylation levels of Akt and mTOR and the levels of prostacyclin. However, the effects of AS-IV decreased with SC79 treatment. In addition, LC3B + BODIPY493/503 fluorescence double staining showed that AS-IV reduced intracellular lipid deposition levels by enhancing autophagy. AS-IV can reduce lipid aggregation in fatty liver cells, which can be related to enhanced hepatocyte autophagy by inhibiting the Akt/mTOR signaling pathway.

Role of Macrophage PIST Protein in Regulating Leishmania major Infection.

PDZ protein interacting specifically with Tc10 or PIST is a mammalian trans-Golgi resident protein that regulates subcellular sorting of plasma membrane receptors. PIST has recently emerged as a key player in regulating viral pathogenesis. Nevertheless, the involvement of PIST in parasitic infections remains unexplored. Leishmania parasites infiltrate their host macrophage cells through phagocytosis, where they subsequently multiply within the parasitophorous vacuole (PV). Host cell autophagy has been found to be important in regulating this parasite infection. Since PIST plays a pivotal role in triggering autophagy through the Beclin 1-PI3KC3 pathway, it becomes interesting to identify the status of PIST during Leishmania infection. We found that while macrophage cells are infected with Leishmania major (L. major), the expression of PIST protein remains unaltered; however, it traffics from the Golgi compartment to PV. Further, we identified that in L. major-infected macrophage cells, PIST associates with the autophagy regulatory protein Beclin 1 within the PVs; however, PIST does not interact with LC3. Reduction in PIST protein through siRNA silencing significantly increased parasite burden, whereas overexpression of PIST in macrophages restricted L. major infectivity. Together, our study reports that the macrophage PIST protein is essential in regulating L. major infectivity.

OPN silencing reduces hypoxic pulmonary hypertension via PI3K-AKT-induced protective autophagy.

Hypoxic pulmonary hypertension (HPH) is a pulmonary vascular disease primarily characterized by progressive pulmonary vascular remodeling in a hypoxic environment, posing a significant clinical challenge. Leveraging data from the Gene Expression Omnibus (GEO) and human autophagy-specific databases, osteopontin (OPN) emerged as a differentially expressed gene, upregulated in cardiovascular diseases such as pulmonary arterial hypertension (PAH). Despite this association, the precise mechanism by which OPN regulates autophagy in HPH remains unclear, prompting the focus of this study. Through biosignature analysis, we observed significant alterations in the PI3K-AKT signaling pathway in PAH-associated autophagy. Subsequently, we utilized an animal model of OPNfl/fl-TAGLN-Cre mice and PASMCs with OPN shRNA to validate these findings. Our results revealed right ventricular hypertrophy and elevated mean pulmonary arterial pressure (mPAP) in hypoxic pulmonary hypertension model mice. Notably, these effects were attenuated in conditionally deleted OPN-knockout mice or OPN-silenced hypoxic PASMCs. Furthermore, hypoxic PASMCs with OPN shRNA exhibited increased autophagy compared to those in hypoxia alone. Consistent findings from in vivo and in vitro experiments indicated that OPN inhibition during hypoxia reduced PI3K expression while increasing LC3B and Beclin1 expression. Similarly, PASMCs exposed to hypoxia and PI3K inhibitors had higher expression levels of LC3B and Beclin1 and suppressed AKT expression. Based on these findings, our study suggests that OPNfl/fl-TAGLN-Cre effectively alleviates HPH, potentially through OPN-mediated inhibition of autophagy, thereby promoting PASMCs proliferation via the PI3K-AKT signaling pathway. Consequently, OPN emerges as a novel therapeutic target for HPH.

Infectious bronchitis virus (IBV) triggers autophagy to enhance viral replication by activating the VPS34 complex.

Autophagy plays an important role in the lifecycle of viruses. However, there is currently a lack of systematic research on the relationship between Infectious Bronchitis Virus (IBV) and autophagy. This study aims to investigate the impact of IBV on autophagy and the role of autophagy in viral replication. We observed that IBV infection increased the expression of microtubule-associated protein 1 light chain 3, a marker of autophagy, decreased the expression of sequestosome 1, and led to elevated intracellular LC3 puncta levels. These findings suggest that IBV infection activates the autophagic process in cells. To investigate the impact of autophagy on the replication of IBV, we utilized rapamycin as an autophagy activator and 3-methyladenine as an autophagy inhibitor. Our results indicate that IBV promotes viral replication by inducing autophagy. Further investigation revealed that IBV induces autophagosome formation by inhibiting the mTOR-ULK1 pathway and activating the activity of vacuolar protein sorting 34 (VPS34), autophagy-related gene 14, and the Beclin-1 complex. VPS34 plays a crucial role in this process, as inhibiting VPS34 protein activity enhances cell proliferation after IBV infection. Additionally, inhibiting VPS34 significantly improves the survival rate of IBV-infected chicks, suppresses IBV replication in the kidney, and alleviates tracheal, lung, and kidney damage caused by IBV infection. In summary, IBV infection can induce autophagy by modulating the mTOR/ULK1 signaling pathway and activating the VPS34 complex, while autophagy serves to promote virus replication.

[Effect of Shikonin on Autophagy and Apoptosis of Human Promyelocytic Leukemia Cells].

OBJECTIVE: To explore the effect of shikonin on autophagy and apoptosis of human promyelocytic leukemia cells and its possible mechanism. METHODS: Human promyelocytic leukemia cells NB4 in the logarithmic growth phase were divided into control group (untreated NB4 cells), shikonin group (0.3 µmol/L shikonin treatment), 740Y-P group (15 µmol/L PI3K/Akt/mTOR pathway activator 740Y-P treatment), shikonin+740Y-P group (0.3 µmol/L shikonin and 15 µmol/L 740Y-P co-treatment), after 24 hours of treatment, the cells were used for subsequent experiments. CCK-8 method was used to detect cell viability, monodansylcadaverine (MDC) staining to detect the aggregation of autophagic vesicles, flow cytometry to detect cell apoptosis, and Western blot to detect the expression of Beclin1, LC3, p62, Bax, cleaved caspase-3, Bcl-2 and PI3K/Akt/mTOR pathway related proteins. RESULTS: Compared with the control group, the purple punctate fluorescence intensity, apoptosis rate, Beclin1, LC3-Ⅱ/LC3-Ⅰ, cleaved caspase-3, and Bax protein expression in NB4 cells were increased in the shikonin group, while OD450 value (24, 48 h) and the expressions of Bcl-2 and p62 proteins were decreased (all P < 0.05). Compared with the control group, the purple punctate fluorescence intensity, apoptosis rate, Beclin1, LC3-Ⅱ/LC3-Ⅰ, cleaved caspase-3, and Bax protein expression in NB4 cells were decreased, while OD450 value (24, 48 h) and the expressions of Bcl-2 and p62 proteins were increased in the 740Y-P group (all P < 0.05). Compared with the shikonin group, the purple punctate fluorescence intensity, apoptosis rate, Beclin1, LC3-Ⅱ/LC3-Ⅰ, cleaved caspase-3, and Bax protein expression in NB4 cells were decreased, while OD450 value (24, 48 h) and the expressions of Bcl-2 and p62 proteins were increased in the shikonin+740Y-P group (all P < 0.05). Compared with the control group, the expression of PI3K/Akt/mTOR pathway related proteins p-PI3K, p-Akt, and p-mTOR in NB4 cells were significantly decreased in the shikonin group, while those in the 740Y-P group were increased (all P < 0.05). Compared with the shikonin group, the expressions of p-PI3K, p-Akt, and p-mTOR proteins in NB4 cells were significantly increased in the shikonin+740Y-P group (all P < 0.05). CONCLUSION: Shikonin may promote autophagy and apoptosis of NB4 cells by inhibiting PI3K/Akt/mTOR pathway.

[HTD4010 attenuates myocardial injury in mice with septic cardiomyopathy by promoting autophagy via the AMPK/mTOR signaling pathway].

OBJECTIVE: To investigate the protective effects of HTD4010 against lipopolysaccharide (LPS)-induced septic cardiomyopathy (SCM) in mice and explore the mechanisms mediating its effect. METHODS: Forty-five male ICR mice were randomized equally into control group, LPS (10 mg/kg) group, and LPS+HTD4010 group (in which 2.5 mg/kg HTD4010 was injected subcutaneously at 1 h and 6 h after LPS injection). Cardiac function of the mice was evaluated by ultrasound, and pathological changes in the myocardial tissues were observed with HE staining. The levels of IL-6 and TNF-α in serum and myocardial tissues were detected using ELISA, and apoptosis of the cardiomyocytes was detected with TUNEL staining. The expression levels of the key proteins associated with apoptosis, autophagy and the AMPK/mTOR pathway in the myocardial tissues were detected using Western blotting. The ultrastructural changes of cardiac myocardial mitochondria was observed with transmission electron microscopy. RESULTS: LPS exposure caused severe myocardial damage in mice, characterized by myocardial fiber rupture, structural disorder, inflammatory cell infiltration, and mitochondrial damage. The LPS-treated mice exhibited significantly decreased cardiac LVEF and FS values, elevated IL-6 and TNF-αlevels in serum and myocardial tissue, and an increased myocardial cell apoptosis rate with enhanced expressions of Bax, p-62 and p-mTOR and lowered expressions of Bcl-2, LC3 II/I, Beclin-1 and p-AMPK (P < 0.05 or 0.01). Treatment of the septic mice with HTD4010 significantly alleviated myocardial damage, increased LVEF and FS values, reduced IL-6 and TNF-α levels in serum and myocardial tissue, decreased cardiomyocyte apoptosis, lowered myocardial expressions of Bax, p-62 and p-mTOR, and increased Bcl-2, LC3 II/I, Beclin-1 and p-AMPK expressions (P < 0.05 or 0.01). CONCLUSION: HTD4010 can attenuate myocardial injury in SCM mice possibly by promoting autophagy via modulating the AMPK/mTOR signaling pathway.

Guasha improves knee osteoarthritis by inhibiting chondrocyte apoptosis and regulating expression of autophagy-related genes and proteins in rats. / åˆ®ç—§å¯¹è†å ³èŠ‚éª¨å ³èŠ‚ç‚Žå¤§é¼ è½¯éª¨ç»†èƒžå‡‹äº¡åŠè‡ªå™¬çš„å½±å“.

OBJECTIVES: To observe the effect of Guasha on inflammation factors, apoptosis and autophagy in the cartilage tissue of knee joint in rats with knee osteoarthritis (KOA), so as to explore its mechanisms underlying improvement of KOA. METHODS: A total of 51 male SD rats were randomized into three groups：blank control, KOA model and Guasha (n= 17 in each group) . The rats in the blank control group received intra-articular injection of 0.9% NaCl solution in the right knee joint. The KOA model was established by intraarticular injection of glutamate sodium iodoacetic acid in the right knee joint. For rats of the Guasha group, Guasha (at a frequency of 1 time/s, and an applied pressure of 0.3-0.5 kgf) was applied to "Yanglingquan" (GB34) and "Xuehai"(SP10) areas of the right leg, once every other day, for 7 consecutive sessions. The circumference of the right knee was measured, The histopathological changes of right knee cartilage were observed after H.E. staining. The contents of inflammatory factors interleukin (IL)-1ß and tumor necrosis factor (TNF)-α in the right knee articular cartilage tissue were assayed using ELISA. The expression levels of autophagy-related key molecule Beclin-1 (homologous series of yeast Atg6), light chain protease complication 3 type II/I (LC3II/LC3 I), ubiquitin binding factor 62 (P62) and cysteine aspartate protease-3 (Caspase-3) mRNAs and proteins of the right knee articular cartilage tissue were measured using real-time fluorescent quantitative PCR and Western blot, separately. The apoptosis of chondrocytes was assayed using TUNEL staining, and the immunoactivity of LC3 determined using immunofluorescence staining. RESULTS: After modeling, the right knee circumfe-rence of the model and Guasha groups was significantly increased compared with the blank control group (P<0.01), and after the intervention, the knee circumference of the Guasha group was markedly decreased in comparison with that of the model group (P<0.05). Results of H.E. staining showed obvious degeneration and defects in the cartilage tissue, necrosis of a large number of chondrocytes, fibrous hyperplasia, accompanied by inflammatory cell infiltration, osteoclast increase, fibroplasia and bone trabecular destruction in the model group, which was relatively milder in the Guasha group. Compared with the blank control group, the expression of Beclin-1 and LC3 mRNAs and proteins, and LC immunofluorescence intensity in the right knee articular cartilage tissue were significantly down-regulated (P<0.01, P<0.001), whereas the expression of P62 and Caspase-3 mRNAs and proteins, the apoptosis rate, contents of IL-1ß and TNF-α in the right knee articular cartilage tissue considerably increased (P<0.01, P<0.001) in the model group. In contrast to the model group, the Guasha group had an apparent increase in the expression levels of Beclin-1 and LC3 mRNAs and proteins and LC immunofluorescence intensity in the right knee articular cartilage tissue (P<0.05), and a pronounced decrease in the expression of P62 and Caspase-3 mRNAs and proteins, the apoptosis rate, and contents of IL-1ß and TNF-α in the right knee articular cartilage tissue (P<0.05, P<0.01). CONCLUSIONS: Guasha stimulation of GB34 and SP10 can improve joint cartilage damage in KOA rats, which may be associated with its functions in inhibiting the excessive release of inflammatory factors and apoptosis, possibly by down-regulating the expression of P62 and Caspase-3 mRNAs and proteins and up-regulating the expression of Beclin-1 and LC3 mRNAs and proteins, and by promoting autophagy of chondrocytes.

Homocysteine metabolites inhibit autophagy by upregulating miR-21-5p, miR-155-5p, miR-216-5p, and miR-320c-3p in human vascular endothelial cells.

Nutritional and genetic deficiencies in homocysteine (Hcy) metabolism lead to hyperhomocysteinemia (HHcy) and cause endothelial dysfunction, a hallmark of atherosclerosis, which is a major cause of cardiovascular disease (CVD). Impaired autophagy causes the accumulation of damaged proteins and organelles and is associated with CVD. Biochemically, HHcy is characterized by elevated levels of Hcy and its metabolites, Hcy-thiolactone and N-Hcy-protein. However, whether these metabolites can dysregulate mTOR signaling and autophagy in endothelial cells is not known. Here, we examined the influence of Hcy-thiolactone, N-Hcy-protein, and Hcy on autophagy human umbilical vein endothelial cells. We found that treatments with Hcy-thiolactone, N-Hcy-protein, or Hcy significantly downregulated beclin 1 (BECN1), autophagy-related 5 (ATG5), autophagy-related 7 (ATG7), and microtubule-associated protein 1 light chain 3 (LC3) mRNA and protein levels. We also found that these changes were mediated by upregulation by Hcy-thiolactone, N-Hcy-protein, and Hcy of autophagy-targeting microRNA (miR): miR-21, miR-155, miR-216, and miR-320c. The effects of these metabolites on levels of miR targeting autophagy as well as on the levels of BECN1, ATG5, ATG7, and LC3 mRNA and protein were abrogated by treatments with inhibitors of miR-21, miR-155, miR-216, and mir320c. Taken together, our findings show that Hcy metabolites can upregulate miR-21, miR-155, miR-216, and mir320c, which then downregulate autophagy in human endothelial cells, important for vascular homeostasis.

ß-asarone inhibits autophagy by activating the PI3K/Akt/mTOR pathway in a rat model of depression in Parkinson's disease.

OBJECTIVE: It is unclear whether ß-asarone has a good antidepressant effect and what is the main mechanism in Depression in Parkinson's disease (DPD) model rats. METHODS: In this study, DPD model rats were screened from 6-OHDA induced rats by sucrose preference test (SPT) and forced swimming test (FST). DPD model rats were divided into eight groups: model group, pramipexole group, ß-asarone low-dose group (ß-asarone 7.5 group), ß-asarone medium-dose group (ß-asarone 15 group), ß-asarone high-dose group (ß-asarone 30 group), 3-MA group, rapamycin group, and PI3K inhibitor group. 28 days after the end of treatment, open field test (OFT), SPT and FST were conducted in rats. The level of α-synuclein (α-syn) in the striatum was determined by enzyme-linked immunosorbent assay (ELISA). The expression of Beclin-1, p62 in the striatum was determined by western blot. The expression of PI3K, p-PI3K, Akt, p-Akt, mTOR, p-mTOR, Beclin-1, and p62 in the hippocampus was determined by western blot. The spine density of neurons in the hippocampus was detected by golgi staining. RESULTS: The results showed that 4-week oral administration of ß-asarone improve the motor and depressive symptoms of DPD model rats, and decrease the content of α-syn in the striatum. ß-asarone inhibited the expression of autophagy in the striatum of DPD model rats. Furthermore, ß-asarone decreased the levels of Beclin-1 protein, increased the expression of p62, p-PI3K, p-AKT, and p-mTOR, and improved the density of neuron dendritic spine in the hippocampus. CONCLUSIONS: We concluded that ß-asarone might improve the behavior of DPD model rats by activating the PI3K/Akt/mTOR pathway, inhibiting autophagy and protecting neuron.

Melittin as an Activator of the Autophagy and Unfolded Protein Response Pathways in Colorectal HCT116 Cell Line.

Background: The potential anticancer effect of melittin has motivated scientists to find its exact molecular mechanism of action. There are few data on the effect of melittin on the UPR and autophagy as two critical pathways involved in tumorigenesis of colorectal and drug resistance. This study aimed to investigate the effect of melittin on these pathways in the colorectal cancer (CRC) HCT116 cells. Methods: MTT method was carried out to assess the cytotoxicity of melittin on the HCT116 cell line for 24, 48, and 72 h. After selecting the optimal concentrations and treatment times, the gene expression of autophagy flux markers (LC3-ßII and P62) and UPR markers (CHOP and XBP-1s) were determined using qRT-PCR. The protein level of autophagy initiation marker (Beclin1) was also determined by Western blotting. Results: MTT assay showed a cytotoxic effect of melittin on the HCT116 cells. The increase in LC3-ßII and decrease in P62 mRNA expression levels, along with the elevation in the Beclin1 protein level, indicated the stimulatory role of melittin on the autophagy. Melittin also significantly enhanced the CHOP and XBP-1s expressions at mRNA level, suggesting the positive role of the melittin on the UPR activation. Conclusion: This study shows that UPR and autophagy can potentially be considered as two key signaling pathways in tumorigenesis, which can be targeted by the BV melittin in the HCT116 cells. Further in vivo evaluations are recommended to verify the obtained results.

Upregulation of miR-499a Targets Beclin1 to Modulate Astrocyte Autophagy and Promote Ischemic Stroke.

OBJECTIVE: To investigate the clinical significance of miR-499a expression in the serum of ischemic stroke patients and its potential mechanism in regulating astrocytes to promote ischemic stroke. METHODS: Serum samples from 99 ischemic stroke patients and 99 healthy individuals were collected and analyzed for miR-499a expression through RT-PCR. Statistical analysis was performed to compare the expression differences between the two groups, and correlation between miR-499a expression and clinical pathological indices in stroke patients was analyzed. MiR-499a mimic, inhibitor, and negative control vectors were constructed and transfected into astrocyte SVGp12 cells. Afterward, miR-499a expression was validated by RT-PCR, cell viability was assessed by CCK8 assay, and apoptosis was detected using flow cytometry. The binding sites of miR-499a and Beclin1 were predicted by the Target-scan database and confirmed by dual luciferase assay. After overexpressing Beclin1, co-transfection with miR-499a mimic or negative control was conducted to observe the reverse effect of miR-499a mimic on Beclin1 overexpression. RESULTS: MiR-499a was significantly upregulated in the stroke group (p<0.001), it was positively correlated with TC (Total Cholesterol), LDL-C (Low-density lipoprotein cholesterol), and APO-A1 (Apolipoprotein A1) (R2>0.3, p<0.001). MiR-499a mimics promoted cell viability while inhibiting apoptosis of astrocytes. MiR-499a targeted Beclin 1 and inhibited its mRNA and protein expression, as well as the expression of autophagy-related proteins LC-3 and p62. MiR-499a could reverse the impact of Beclin1 overexpression on SVGp12 astrocyte proliferation and apoptosis. CONCLUSION: Serum miR-499a in stroke patients may serve as a potential diagnostic indicator. MiR-499a-mediated inhibition of Beclin 1, subsequently leading to suppression of astrocytic autophagy and viability, may represent a pivotal mechanism underlying its promotion of IS.

Effects of the combination of Epimedii Folium and Ligustri Lucidi Fructus on apoptosis and autophagy in SOP rats and osteoblasts via PI3K/AKT/mTOR pathway.

BACKGROUND: This study aimed to investigate the effects of the combination of Epimedii Folium (EF) and Ligustri Lucidi Fructus (LLF) on regulating apoptosis and autophagy in senile osteoporosis (SOP) rats. METHODS: Firstly, we identified the components in the decoction and drug-containing serum of EL (EF&LLF) by Ultra performance liquid chromatography-quadrupole-time of flight-mass spectrometry (UPLC-Q-TOF-MS). Secondly, SOP rats were treated with EF, LLF, EL and caltrate to evaluate the advantages of EL. Finally, H2O2-, chloroquine-, and MHY1485-induced osteoblasts were treated with different doses of EL to reveal the molecular mechanism of EL. We detected bone microstructure, oxidative stress levels, ALP activity and the expressions of Bax, Bcl-2, caspase3, P53, Beclin-1, p-PI3K, PI3K, p-Akt, Akt, p-mTOR, mTOR, and LC3 in vivo and in vitro. RESULTS: 36 compounds in EL decoction and 23 in EL-containing serum were identified, including flavonoids, iridoid terpenoids, phenylethanoid glycosides, polyols and triterpenoids. EL could inhibit apoptosis activity and increase ALP activity. In SOP rats and chloroquine-inhibited osteoblasts, EL could improve bone tissue microstructure and osteoblasts functions by upregulating Bcl-2, Beclin1, and LC3-II/LC3-I, while downregulating p53 in all treatment groups. In H2O2-induced osteoblasts, EL could upregulate the protein and mRNA expressions of Bcl-2 while downregulate LC3-II/LC3-I, p53 and Beclin1. Besides, EL was able to down-regulate PI3K/AKT/mTOR pathway which activated in SOP rats and MHY1485-induced osteoblasts. CONCLUSIONS: These findings demonstrate that EL with bone protective effects on SOP rats by regulating autophagy and apoptosis via PI3K/Akt/mTOR signaling pathway, which might be an alternative medicine for the treatment of SOP.

Beclin-1-Derived Peptide MP1 Attenuates Renal Fibrosis by Inhibiting the Wnt/ß-Catenin Pathway.

Renal fibrosis is distinguished by the abnormal deposition of extracellular matrix and progressive loss of nephron function, with a lack of effective treatment options in clinical practice. In this study, we discovered that the Beclin-1-derived peptide MP1 significantly inhibits the abnormal expression of fibrosis and epithelial-mesenchymal transition-related markers, including α-smooth muscle actin, fibronectin, collagen I, matrix metallopeptidase 2, Snail1, and vimentin both in vitro and in vivo. H&E staining was employed to evaluate renal function, while serum creatinine (Scr) and blood urea nitrogen (BUN) were used as main indices to assess pathologic changes in the obstructed kidney. The results demonstrated that daily treatment with MP1 during the 14-day experiment significantly alleviated renal dysfunction and changes in Scr and BUN in mice with unilateral ureteral obstruction. Mechanistic research revealed that MP1 was found to have a significant inhibitory effect on the expression of crucial components involved in both the Wnt/ß-catenin and transforming growth factor (TGF)-ß/Smad pathways, including ß-catenin, C-Myc, cyclin D1, TGF-ß1, and p-Smad/Smad. However, MP1 exhibited no significant impact on either the LC3II/LC3I ratio or P62 levels. These findings indicate that MP1 improves renal physiologic function and mitigates the fibrosis progression by inhibiting the Wnt/ß-catenin pathway. Our study suggests that MP1 represents a promising and novel candidate drug precursor for the treatment of renal fibrosis. SIGNIFICANCE STATEMENT: This study indicated that the Beclin-1-derived peptide MP1 effectively mitigated renal fibrosis induced by unilateral ureteral obstruction through inhibiting the Wnt/ß-catenin pathway and transforming growth factor-ß/Smad pathway, thereby improving renal physiological function. Importantly, unlike other Beclin-1-derived peptides, MP1 exhibited no significant impact on autophagy in normal cells. MP1 represents a promising and novel candidate drug precursor for the treatment of renal fibrosis focusing on Beclin-1 derivatives and Wnt/ß-catenin pathway.

Arabidopsis BECLIN1-induced autophagy mediates reprogramming in tapetal programmed cell death by altering the gross cellular homeostasis.

In flowering plants, the tapetum degeneration in post-meiotic anther occurs through developmental programmed cell death (dPCD), which is one of the most critical and sensitive steps for the proper development of male gametophytes and fertility. Yet the pathways of dPCD, its regulation, and its interaction with autophagy remain elusive. Here, we report that high-level expression of Arabidopsis autophagy-related gene BECLIN1 (BECN1 or AtATG6) in the tobacco tapetum prior to their dPCD resulted in developmental defects. BECN1 induces severe autophagy and multiple cytoplasm-to-vacuole pathways, which alters tapetal cell reactive oxygen species (ROS)-homeostasis that represses the tapetal dPCD. The transcriptome analysis reveals that BECN1- expression caused major changes in the pathway, resulting in altered cellular homeostasis in the tapetal cell. Moreover, BECN1-mediated autophagy reprograms the execution of tapetal PCD by altering the expression of the key developmental PCD marker genes: SCPL48, CEP1, DMP4, BFN1, MC9, EXI1, and Bcl-2 member BAG5, and BAG6. This study demonstrates that BECN1-mediated autophagy is inhibitory to the dPCD of the tapetum, but the severity of autophagy leads to autophagic death in the later stages. The delayed and altered mode of tapetal degeneration resulted in male sterility.

[Effect of Bushen Huoxue（） recipe on autophagy of ovariectomized rat chondrocytes based on Akt/mTOR signaling pathway].

OBJECTIVE: To investigate whether Bushen Huoxue recipe can protect articular cartilage by regulating Akt/mTOR signaling pathway to promote the autophagy of chondrocytes in ovariectomized rats. METHODS: Among 30 SPF 12-week-old female SD rats weighing （247.0±7.0） g, 6 were randomly selected as the blank control group, and the remaining rats were randomly divided into model group, BSHXR-L group, BSHXR-M group and BSHXR-H group, with 6 rats in each group. The protective effect of Bushen Huoxue recipe on articular cartilage injury in rats was determined by visual observation score, muscovine O-solid green staining and immunohistochemistry. The expression of autophagy related proteins was detected by Western-blot, and the relative expression of Akt, mTOR and downstream autophagy genes was detected by qPCR. RESULTS: After modeling, BSHXR （L, M, H） groups could alleviate the histological damage of cartilage. Immunohistochemistry showed that the expression of Collagen-Ⅱand Aggrecan gradually increased, and the expression of MMP-13 gradually decreased, and the differences between BSHXR-M and BSHXR-H groups and model group were statistically significant （P<0.05）. The results of Western-blot showed that the autophagy pathway proteins p-Akt/Akt and p-mTOR/mTOR were inhibited in the BSHXR（L, M, H） groups, and the expressions of downstream proteins Beclin-1 and LC3Ⅱwere gradually increased, while p62 was gradually decreased, showing a dose effect. QPCR results showed that BSHXR（L, M, H） groups could promote the relative expression of Beclin-1 and LC3ⅡmRNA, and inhibit the relative expression of p62, Akt, mTOR mRNA, and the differences were statistically significant compared with model group （P<0.05）. CONCLUSION: Bushen Huoxue recipe can enhance the cartilage autophagy response by inhibiting the Akt/mTOR signaling pathway, and then protect the cartilage.

Cisplatin Nephrotoxicity Is Critically Mediated by the Availability of BECLIN1.

Cisplatin nephrotoxicity is a critical limitation of solid cancer treatment. Until now, the complex interplay of various pathophysiological mechanisms leading to proximal tubular cell apoptosis after cisplatin exposure has not been fully understood. In our study, we assessed the role of the autophagy-related protein BECLIN1 (ATG6) in cisplatin-induced acute renal injury (AKI)-a candidate protein involved in autophagy and with putative impact on apoptosis by harboring a B-cell lymphoma 2 (BCL2) interaction site of unknown significance. By using mice with heterozygous deletion of Becn1, we demonstrate that reduced intracellular content of BECLIN1 does not impact renal function or autophagy within 12 months. However, these mice were significantly sensitized towards cisplatin-induced AKI, and by using Becn1+/-;Sglt2-Cre;Tomato/EGFP mice with subsequent primary cell analysis, we confirmed that nephrotoxicity depends on proximal tubular BECLIN1 content. Mechanistically, BECLIN1 did not impact autophagy or primarily the apoptotic pathway. In fact, a lack of BECLIN1 sensitized mice towards cisplatin-induced ER stress. Accordingly, the ER stress inhibitor tauroursodeoxycholic acid (TUDCA) blunted cisplatin-induced cell death in Becn1 heterozygosity. In conclusion, our data first highlight a novel role of BECLIN1 in protecting against cellular ER stress independent from autophagy. These novel findings open new therapeutic avenues to intervene in this important intracellular stress response pathway with a promising impact on future AKI management.

BECLIN1 is essential for intestinal homeostasis involving autophagy-independent mechanisms through its function in endocytic trafficking.

Autophagy-related genes have been closely associated with intestinal homeostasis. BECLIN1 is a component of Class III phosphatidylinositol 3-kinase complexes that orchestrate autophagy initiation and endocytic trafficking. Here we show intestinal epithelium-specific BECLIN1 deletion in adult mice leads to rapid fatal enteritis with compromised gut barrier integrity, highlighting its intrinsic critical role in gut maintenance. BECLIN1-deficient intestinal epithelial cells exhibit extensive apoptosis, impaired autophagy, and stressed endoplasmic reticulum and mitochondria. Remaining absorptive enterocytes and secretory cells display morphological abnormalities. Deletion of the autophagy regulator, ATG7, fails to elicit similar effects, suggesting additional novel autophagy-independent functions of BECLIN1 distinct from ATG7. Indeed, organoids derived from BECLIN1 KO mice show E-CADHERIN mislocalisation associated with abnormalities in the endocytic trafficking pathway. This provides a mechanism linking endocytic trafficking mediated by BECLIN1 and loss of intestinal barrier integrity. Our findings establish an indispensable role of BECLIN1 in maintaining mammalian intestinal homeostasis and uncover its involvement in endocytic trafficking in this process. Hence, this study has important implications for our understanding of intestinal pathophysiology.

VHL suppresses autophagy and tumor growth through PHD1-dependent Beclin1 hydroxylation.

The Von Hippel-Lindau (VHL) protein, which is frequently mutated in clear-cell renal cell carcinoma (ccRCC), is a master regulator of hypoxia-inducible factor (HIF) that is involved in oxidative stresses. However, whether VHL possesses HIF-independent tumor-suppressing activity remains largely unclear. Here, we demonstrate that VHL suppresses nutrient stress-induced autophagy, and its deficiency in sporadic ccRCC specimens is linked to substantially elevated levels of autophagy and correlates with poorer patient prognosis. Mechanistically, VHL directly binds to the autophagy regulator Beclin1, after its PHD1-mediated hydroxylation on Pro54. This binding inhibits the association of Beclin1-VPS34 complexes with ATG14L, thereby inhibiting autophagy initiation in response to nutrient deficiency. Expression of non-hydroxylatable Beclin1 P54A abrogates VHL-mediated autophagy inhibition and significantly reduces the tumor-suppressing effect of VHL. In addition, Beclin1 P54-OH levels are inversely correlated with autophagy levels in wild-type VHL-expressing human ccRCC specimens, and with poor patient prognosis. Furthermore, combined treatment of VHL-deficient mouse tumors with autophagy inhibitors and HIF2α inhibitors suppresses tumor growth. These findings reveal an unexpected mechanism by which VHL suppresses tumor growth, and suggest a potential treatment for ccRCC through combined inhibition of both autophagy and HIF2α.

Protective effects of naringin on colistin-induced damage in rat testicular tissue: Modulating the levels of Nrf-2/HO-1, AKT-2/FOXO1A, Bax/Bcl2/Caspase-3, and Beclin-1/LC3A/LC3B signaling pathways.

Antimicrobial agent resistance has become a growing health issue across the world. Colistin (COL) is one of the drugs used in the treatment of multidrug-resistant bacteria resulting in toxic effects. Naringin (NRG), a natural flavonoid, has come to the fore as its antioxidant, anti-inflammatory, and antiapoptotic activities. The aim of the present study was to determine whether NRG has protective effects on COL-induced toxicity in testicular tissue. Thirty-five male Spraque rats were randomly divided into five groups (n = 7 per group): Control, COL, NRG, COL + NRG 50, COL + NRG 100. COL (15 mg/kg b.w., i.p., once per/day), and NRG (50 or 100 mg/kg, oral, b.w./once per/day) were administered for 7 days. The parameters of oxidative stress, inflammation, apoptosis, and autophagic damage were evaluated by using biochemical, molecular, western blot, and histological methods in testicular issues. NRG treatment reversed the increased malondialdehyde level and reduced antioxidants (superoxide dismutase, catalase, glutathione peroxidase, and glutathione) levels due to COL administration (p < 0.001), and oxidative stress damage was mitigated. Nuclear factor erythroid 2-related factor-2 pathway, one of the antioxidant defence systems, was stimulated by NRG (p < 0.001). NRG treatment reduced the levels of markers for the pathways of apoptotic (p < 0.001) and autophagic (p < 0.001) damages induced by COL. Sperm viability and the live/dead ratio were reduced by COL but enhanced by NRG treatment. Testicular tissue integrity was damaged by COL but showed a tendency to improve by NRG. In conclusion, COL exhibited toxic effect on testicular tissue by elevating the levels of oxidative stress, apoptosis, autophagy, inflammation, and tissue damage. NRG demonstrated a protective effect by alleviating toxic damage.

Regulatory mechanism of perinatal nonylphenol exposure on cardiac mitochondrial autophagy and the PINK1/Parkin signaling pathway in male offspring rats.

OBJECTIVE: This study investigated whether perinatal exposure to nonylphenol (NP) induces mitochondrial autophagy (i.e., mitophagy) damage in neonatal rat cardiomyocytes (NRCMs) and whether the PINK1/Parkin signaling pathway is involved in NP-induced primary cardiomyocyte injury. METHODS AND RESULTS: In vivo: Perinatal NP exposure increased apoptosis and mitochondrial damage in NRCMs. Mitochondrial swelling and autophagosome-like structures with multiple concentric membranes were observed in the 100 mg/kg NP group, with an increase in the number of autophagosomes. Disorganized fiber arrangement and elevated serum myocardial enzyme levels were observed with increasing NP dosage. Additionally, NP exposure led to increased MDA levels and decreased SOD activity and ATP levels in myocardial tissue. The mRNA expression levels of autophagy-related genes, including Beclin-1, p62, and LC3B, as well as the expression of mitochondrial autophagy-related proteins (PINK1, p-Parkin, Parkin, Beclin-1, p62, LC3-I, LC3-II, and LC3-II/I) and apoptosis-related proteins (Bax and caspase-3), increased, whereas the expression levels of the mitochondrial membrane protein TOMM20 and the anti-apoptotic protein Bcl-2 decreased. In vitro: NP increased ROS levels, LDH release, and decreased ATP levels in NRCMs. CsA treatment significantly inhibited the expression of autophagy-related proteins (Beclin-1, LC3-II/I, and p62) and apoptosis-related proteins (caspase-3 and Bax), increased the expression levels of TOMM20 and Bcl-2 proteins, increased cellular ATP levels, and inhibited LDH release. The inhibition of the PINK1/Parkin signaling pathway suppressed the expression of mitochondrial autophagy-related proteins (PINK1, p-Parkin, Parkin, Beclin-1, LC3-II/I, and p62) and apoptosis-related proteins (caspase-3 and Bax), increased TOMM20 and Bcl-2 protein expression, increased ATP levels, and decreased LDH levels in NRCMs. CONCLUSIONS: This study is novel in reporting that perinatal NP exposure induced myocardial injury in male neonatal rats, thereby inducing mitophagy. The PINK1/Parkin signaling pathway was involved in this injury by regulating mitophagy.