Oligodendrocyte lineage cells, including oligodendrocyte precursor cells (OPCs) and oligodendrocytes (OLs), are essential in establishing and maintaining brain circuits. Autophagy is a conserved process that keeps the quality of organelles and proteostasis. The role of autophagy in oligodendrocyte lineage cells remains unclear. The present study shows that autophagy is required to maintain the number of OPCs/OLs and myelin integrity during brain aging. Inactivation of autophagy in oligodendrocyte lineage cells increases the number of OPCs/OLs in the developing brain while exaggerating the loss of OPCs/OLs with brain aging. Inactivation of autophagy in oligodendrocyte lineage cells impairs the turnover of myelin basic protein (MBP). It causes MBP to accumulate in the cytoplasm as multimeric aggregates and fails to be incorporated into integral myelin, which is associated with attenuated endocytic recycling. Inactivation of autophagy in oligodendrocyte lineage cells impairs myelin integrity and causes demyelination. Thus, this study shows autophagy is required to maintain myelin quality during aging by controlling the turnover of myelin components.
Animals ; Autophagy/physiology* ; Oligodendroglia/metabolism* ; Myelin Sheath/physiology* ; Aging/pathology* ; Myelin Basic Protein/metabolism* ; Cell Lineage/physiology* ; Mice ; Oligodendrocyte Precursor Cells ; Mice, Inbred C57BL ; Brain/cytology* ; Cells, Cultured ; Cell Count

Alzheimer's disease (AD) poses one of the most urgent medical challenges in the 21st century as it affects millions of people. Unfortunately, the etiopathogenesis of AD is not yet fully understood and the current pharmacotherapy options are somewhat limited. Here, we report a novel inhibitor, Compound 44, for targeting cholinesterases, amyloid-β (Aβ) aggregation, and glycogen synthase kinase 3β (GSK-3β) simultaneously with the aim of achieving symptomatic relief and disease modification in AD therapy. We found that Compound 44 had good inhibitory effects on all intended targets with IC₅₀s of submicromolar or better, significant neuroprotective effects in cell models, and beneficial improvement of cognitive deficits in the triple transgenic AD (3 × Tg AD) mouse model. Moreover, we showed that Compound 44 acts as an autophagy regulator by inducing nuclear translocation of transcription factor EB through GSK-3β inhibition, enhancing the biogenesis of lysosomes and elevating autophagic flux, thus ameliorating the amyloid burden and tauopathy, as well as mitigating the disease phenotype. Our results suggest that triple-target inhibition via Compound 44 could be a promising strategy that may lead to the development of effective therapeutic approaches for AD.
Animals ; Alzheimer Disease/genetics* ; Mice, Transgenic ; Glycogen Synthase Kinase 3 beta/metabolism* ; Disease Models, Animal ; Mice ; Amyloid beta-Peptides/metabolism* ; Cholinesterase Inhibitors/therapeutic use* ; Humans ; Autophagy/drug effects* ; Cognitive Dysfunction/pathology* ; Neuroprotective Agents/pharmacology*

Hypoxia and aberrant activation of epidermal growth factor receptor (EGFR) are considered important features of various malignancies. However, whether hypoxia can directly trigger EGFR activation and its clinical implications remain unclear. In this study, we demonstrated that in oral cancer, a typical hypoxic tumor, hypoxia can induce chronic but constitutive phosphorylation of wild-type EGFR in the absence of ligands. Oral cancer cell lines exhibit different EGFR phosphorylation responses to hypoxia. In hypoxic HN4 and HN6 cells, ubiquitination-mediated endocytosis, lysosomal sorting, and degradation lead to low levels of EGFR phosphorylation. However, in CAL-27 and HN30 cells, a novel HIF-1α-induced long noncoding RNA (lncRNA), EUDAL, can compete with the E3 ligase/adaptor complex c-Cbl/Grb2 for binding to EGFR, stabilizing phosphorylated EGFR (pEGFR) and resulting in sustained activation of EGFR and its downstream STAT3/BNIP3 signaling. STAT3/BNIP3-mediated autophagy leads to antitumor drug resistance. A high EUDAL/EGFR/STAT3/autophagy pathway activation predicts poor response to chemotherapy in oral cancer patients. Collectively, hypoxia can induce noncanonical ligand-independent EGFR phosphorylation. High EUDAL expression facilitates sustained EGFR phosphorylation in hypoxic tumor cells and leads to autophagy-related drug resistance.
Humans ; ErbB Receptors/metabolism* ; Mouth Neoplasms/pathology* ; RNA, Long Noncoding/genetics* ; Drug Resistance, Neoplasm/genetics* ; Cell Line, Tumor ; Phosphorylation ; Signal Transduction ; STAT3 Transcription Factor/metabolism* ; Cell Hypoxia ; Autophagy ; Proto-Oncogene Proteins c-cbl/metabolism*

OBJECTIVE: To investigate the effects of calcitonin gene-related peptide (CGRP) on autophagy in hypoxic/reoxygenated (H/R) cardiomyocytes and its relationship with the phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) signaling pathway. METHODS: The rat cardiomyocyte cell line H9c2 was routinely cultured in vitro and passaged for experiments when the cells grew to 80% fusion. (1) CGRP dosage screening experiment: the cells were divided into blank control group, H/R group and different dosages of CGRP pretreatment groups. H9c2 cells were placed in a closed hypoxia chamber for 2 hours and then reoxygenated in a conventional incubator for 12 hours to prepare the H/R model. The CGRP pretreatment groups were pretreated with 0.01, 0.1, 0.5, 1, 5, and 10 μmol/L CGRP before the modeling process. The blank control group was not given any treatment. Cell counting kit-8 (CCK-8) was used to detect the cell survival rate, and the most suitable drug dosage was screened out. (2) Intervention experiment: H9c2 cells were divided into blank control group, H/R group, CGRP+H/R group, and CGRP+PI3K target inhibitor ly294002 (LY)+H/R group. H/R group was prepared as cellular H/R model. CGRP (1 μmol/L) alone or in combination with LY (10 μmol/L) was administered to CGRP+H/R group and CGRP+LY+H/R group, respectively, prior to the preparation of cellular H/R model. The blank control group was cultured routinely without treatment. The cell survival rate was detected by CCK-8. The level of lactate dehydrogenase (LDH) release was detected by colorimetric assay. The expressions of autophagy-related proteins [autophagy effector protein Beclin-1, microtubule-associated protein 1 light chain 3-II (LC3-II), autophagy protein p62] and PI3K/Akt/mTOR signaling pathway proteins [phosphorylated Akt (p-Akt), phosphorylated mTOR (p-mTOR)] were detected by Western blotting. RESULTS: (1) Results of CGRP dosage screening experiment: compared with the blank control group, the cell survival rate of the H/R group decreased significantly; and after giving 0.1, 0.5, 1, 5 μmol/L CGRP for pretreatment, the cell survival rate increased significantly, and intervention effect of 1 μmol/L CGRP was the best, and the difference was statistically significant when compared with that of the H/R group [(74.23±6.18)% vs. (23.43±4.09)%, P < 0.01], so it was used as the intervention dosage for the subsequent experiment. (2) Intervention experiment results: compared with the blank control group, the cell survival rate in the H/R group was significantly reduced, the level of LDH release was significantly increased, the protein expressions of Beclin-1 and LC3-II were significantly increased, and the protein expressions of p62, p-Akt and p-mTOR were significantly reduced, indicating that the death of cardiomyocytes occurred after the treatment of H/R and was accompanied by the elevation of autophagy level, and this process was associated with the activation of PI3K/Akt/mTOR signaling pathway. Compared with the H/R group, CGRP pretreatment increased cell survival rate [(76.02±2.43)% vs. (46.15±3.29)%, P < 0.01], decreased the level of LDH release (U/L: 169.83±11.65 vs. 590.17±34.50, P < 0.01), and down-regulated the protein expressions of Beclin-1 and LC3-II [Beclin-1 protein (Beclin-1/β-actin): 1.27±0.15 vs. 1.93±0.19, LC3-II protein (LC3-II/LC3-I): 1.27±0.13 vs. 1.98±0.18, both P < 0.01], up-regulated the protein expressions of p62, p-Akt, p-mTOR [p62 protein (p62/β-actin): 0.96±0.02 vs. 0.63±0.05, p-Akt protein (p-Akt/Akt): 0.76±0.04 vs. 0.48±0.02, p-mTOR protein (p-mTOR/mTOR): 1.13±0.09 vs. 0.68±0.15, all P < 0.05], suggesting that CGRP was able to reduce the H/R-induced cardiomyocyte injury, and this process was accompanied by a decrease in the level of cellular autophagy and activation of the PI3K/Akt/mTOR signaling pathway. Compared with the CGRP+H/R group, the cell survival rate was significantly lower than that in the CGRP+LY+H/R group [(56.95±6.63)% vs. (76.02±2.43)%, P < 0.01], LDH release level was significantly higher (U/L: 436.00±27.44 vs. 169.83±11.65, P < 0.01), and the protein expressions of Beclin-1 and LC3-II were significantly up-regulated [Beclin-1 protein (Beclin-1/β-actin): 1.63±0.12 vs. 1.27±0.15, LC3-II protein (LC3-II/LC3-I): 1.61±0.13 vs. 1.27±0.13, both P < 0.01], and significantly down-regulated p62, p-Akt, and p-mTOR protein expressions [p62 protein (p62/β-actin): 0.57±0.09 vs. 0.96±0.02, p-Akt protein (p-Akt/Akt): 0.45±0.01 vs. 0.76±0.04, p-mTOR protein (p-mTOR/mTOR): 0.66±0.06 vs. 1.13±0.09, all P < 0.05], suggesting that PI3K-targeted inhibitor was able to reverse the protective effect of CGRP on H/R cells. CONCLUSIONS CGRP pretreatment attenuated H/R-induced cardiomyocyte injury, increased cell survival rate, and reduced cellular LDH release. This effect may be achieved through inhibiting the activation of PI3K/Akt/mTOR signaling pathway.
Animals ; Myocytes, Cardiac/drug effects* ; Signal Transduction/drug effects* ; Rats ; TOR Serine-Threonine Kinases/metabolism* ; Calcitonin Gene-Related Peptide/pharmacology* ; Proto-Oncogene Proteins c-akt/metabolism* ; Autophagy/drug effects* ; Cell Line ; Cell Hypoxia ; Phosphatidylinositol 3-Kinases/metabolism*

OBJECTIVE: To investigate the impact of autophagy on cardiac tissue injury following common bile duct ligation (CBDL) in rats. METHODS: Twenty-four SPF grade healthy adult male Sprague-Dawley (SD) rats were randomly divided into four groups, with 6 rats in each group. The sham-operated (Sham) group underwent only dissection of the common bile duct without ligation. The CBDL group underwent CBDL to simulate jaundice-induced myocardial injury. The autophagy inhibitor 3-methyladenine (3-MA)+CBDL group was intraperitoneally injected with 15 mg/kg 3-MA 2 hours before modeling, and then injected once every other day. The CBDL+autophagy enhancer rapamycin (Rapa) group was intraperitoneally injected with Rapa 1 mg/kg 0.5 hour after modeling, and then injected once every other day. The rats in each group were sacrificed 2 weeks after surgery, and blood was taken from the inferior vena cava. Serum total bilirubin (TBil), alanine transaminase (ALT), aspartate transaminase (AST), lactate dehydrogenase (LDH), and MB isoenzyme of creatine kinase (CK-MB) were detected by using a fully automated animal biochemical analyzer. Serum oxidative stress marker superoxide dismutase (SOD) activity and malondialdehyde (MDA) content were detected by colorimetric assay. The heart tissues of rats were taken and pathological changes were observed under a light microscope after hematoxylin-eosin (HE) staining. Transmission electron microscope was used to observe autophagosomes after double staining with uranyl acetate and lead citrate. The expressions of autophagy-related proteins were detected using Western blotting. RESULTS: Compared with the Sham group, the serum SOD activity of rats in the CBDL group was significantly decreased, while the serum MDA, TBil, ALT, AST, LDH, and CK-MB were significantly increased; the expressions of autophagy-related proteins Beclin-1 and microtubule-associated protein 1 light chain 3-II/I (LC3-II/I) were significantly increased, and p62 protein expression was significantly decreased. Autophagosomes were seen under electron microscopy in the CBDL group, and cardiac histopathological morphology showed focal necrosis in the myocardium as well as infiltration of inflammatory cells, dilatation of small interstitial blood vessels, and myocardial fiber degeneration. Compared with the CBDL group, cardiac tissue injury in rats was attenuated by pretreatment with the autophagy inhibitor 3-MA, with a decrease in inflammatory cell infiltration in myocardial tissue, a reduction in interstitial vasodilatation, and a decrease in the area of myocardial fibrosis; a decrease in the number of autophagosomes by electron microscopy; and a further rise in the viability of serum TBil, ALT, and AST [TBil (μmol/L): 184.40±6.74 vs. 120.70±16.93, ALT (U/L): 501.10±62.18 vs. 178.80±22.30, AST (U/L): 806.50±76.92 vs. 275.50±55.81, all P < 0.01], as well as a decrease in the levels of serum SOD, MDA, LDH, and CK-MB [SOD (kU/L): 85.00±5.29 vs. 107.50±7.86, MDA (μmol/L): 10.72±0.93 vs. 15.06±1.88, LDH (U/L): 387.40±119.50 vs. 831.30±84.35, CK-MB (U/L): 320.10±14.04 vs. 814.70±75.66, all P < 0.05]. The expressions of the autophagy-related proteins Beclin-1 and LC3-II/I in cardiac tissues were significantly decreased [Beclin-1 protein (Beclin-1/GAPDH): 0.67±0.04 vs. 0.89±0.01, LC3-II/I ratio: 0.93±0.03 vs. 1.09±0.01, both P < 0.01], and p62 protein expression was significantly increased (p62/GAPDH: 0.99±0.01 vs. 0.60±0.01, P < 0.01). In contrast, compared with the CBDL group, after administration of the autophagy enhancer Rapa, the rats showed increased cardiac tissue injury, increased inflammatory cell infiltration in myocardial tissues, increased interstitial vasodilatation, and increased area of myocardial fibrosis; an increase in autophagosomes was seen by electron microscopy; the change tendency of serum biochemical indicators and proteins in myocardial tissues were opposite with autophagy inhibition group with a decrease in serum TBil, ALT, and AST [TBil (μmol/L): 22.00±3.21 vs. 120.70±16.93, ALT (U/L): 72.13±5.97 vs. 178.80±22.30, AST (U/L): 135.20±12.95 vs. 275.50±55.81, all P < 0.05], as well as a increase in the levels of serum SOD, MDA, LDH, and CK-MB [SOD (kU/L): 208.00±2.65 vs. 107.50±7.86, MDA (μmol/L): 20.38±0.40 vs. 15.06±1.88, LDH (U/L): 1 268.00±210.90 vs. 831.30±84.35, CK-MB (U/L): 1 150.00±158.70 vs. 814.70±75.66, all P < 0.05]. The protein expressions of Beclin-1 and LC3-II/I in cardiac tissues were significantly increased [Beclin-1 protein (Beclin-1/GAPDH): 0.96±0.01 vs. 0.89±0.01, LC3-II/I ratio: 1.19±0.01 vs. 1.09±0.01, both P < 0.05], and p62 protein expression was significantly decreased (p62/GAPDH: 0.19±0.02 vs. 0.60±0.01, P < 0.01). CONCLUSIONS Activation of autophagy in CBDL rats led to myocardial tissue injury and reduced cardiac function. Inhibition of autophagy improved cardiac tissue injury in CBDL rats, while increasing autophagy exacerbated myocardial tissue injury.
Animals ; Autophagy ; Rats, Sprague-Dawley ; Male ; Ligation ; Rats ; Common Bile Duct/surgery* ; Myocardium/pathology* ; Adenine/pharmacology*

OBJECTIVE: To investigate the mechanism of autophagy in regulating bacterial translocation in intestinal infection caused by hypervirulent Klebsiella pneumonia (hvKp) and explore the method of reducing translocation infection of intestinal bacteria. METHODS: Fifty C57BL/6J mice were divided into gavage group (n = 40) and control group (CO group, n = 10). The gavage group was orally administered with 200 μL/d of hvKp (colony count of 10⁹ CFU/mL) continuously for 5 days to establish a hvKp intestinal infection model. CO group was given an equal amount of normal saline. After the experiment, the mice were anesthetized with lsofluraneand euthanized with cervical dislocation under anesthesia. Peripheral venous blood of mice was collected to detect bacterial translocation by 16S rDNA sequencing, then divided into translocation group (BT+ group) and non-translocation group (BT- group). Hematoxylin-eosin (HE) staining was used to evaluate intestinal morphology. The ultrastructural changes of intestinal tissues were observed by electron microscope. The levels of intestinal oxidative stress indicators such as superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione peroxidase (GPx) were measured. Translocation was detected by in situ hybridization. The expression of tight junction protein microtubule-associated protein 1 light chain 3-II (LC3-II) and autophagy protein Beclin-1 were measured by Western blotting. The mRNA expression of tight junction proteins ZO-1 and Claudin-2 were detected by reverse transcription-polymerase chain reaction (RT-PCR). The expression of autophagy protein and tight junction protein were observed by immunofluorescence. RESULTS: Two out of 40 mice in the gavage group died after developing aspiration pneumonia. All mice in the CO group survived. The 16S rDNA sequencing results showed that no bacteria were detected in the peripheral blood of the CO group, but bacteria were detected in the peripheral blood of 18 mice in the gavage group, with a bacterial translocation rate of 47.4%. The BT- and BT+ groups showed intestinal mucosal tissue damage, with severe damage in the BT+ group. Compared with the CO group, the level of MDA in the BT- and BT+ groups were significantly increased, while the activities of SOD and GPx were significantly decreased. Compared with the BT- group, the MDA level in the BT+ group further increased, while the SOD and GPx activities further decreased [MDA (mmol/mg): 2.98±0.11 vs. 2.48±0.11, SOD (U/mg): 62.40±5.45 vs. 73.40±4.08, GPx (U/mg): 254.72±10.80 vs. 303.55±8.57, all P < 0.01]. The results of in situ hybridization detection showed that after continuous gastric lavage for 5 days, displaced hvKp was detected in the intestinal mucosal lamina propria and liver tissue of the BT+ group. Compared with the CO group, the protein expressions of LC3-II and Beclin-1 in the BT- and BT+ groups were significantly increased. The protein expressions of LC3-II and Beclin-1 in the BT+ group were obviously lower than those in the BT- group (LC3-II/β-actin: 0.38±0.04 vs. 0.70±0.09, Beclin-1/β-actin: 0.62±0.05 vs. 0.86±0.05, both P < 0.01), and there were autophagosomes in the intestinal mucosa. These results indicated that intestinal mucosal autophagy was activated after hvKp continuous gavage. Compared with CO group, the mRNA expressions of ZO-1 and Claudin-2 in the BT- and BT+ groups were significantly decreased. Compared with the BT- group, the mRNA expressions of ZO-1 and Claudin-2 in the BT+ group was further reduced [ZO-1 mRNA (2^-ΔΔCT): 0.78±0.06 vs. 0.88±0.06, Claudin-2 mRNA (2^-ΔΔCT): 0.40±0.04 vs. 0.70±0.06, both P < 0.01]. The immunofluorescence results showed that the fluorescence intensity of LC3-II, Beclin-1, ZO-1, and Claudin-2 in the BT+ group was significantly lower than that in the BT- group. CONCLUSION HvKp can activate intestinal mucosal autophagy and reduce the damage to intestinal mucosal barrier function by down-regulating oxidative stress level, reduce the occurrence of bacterial translocation.
Animals ; Oxidative Stress ; Mice, Inbred C57BL ; Autophagy ; Intestinal Mucosa/microbiology* ; Bacterial Translocation ; Mice ; Klebsiella Infections/microbiology* ; Superoxide Dismutase/metabolism* ; Beclin-1

Sepsis is a life-threatening organ dysfunction syndrome caused by a dysregulated host response to infection. Septic acute kidney injury (SAKI) is one of the most common complications of sepsis, and the occurrence of acute kidney injury (AKI) indicates that the patient's condition is critical with a poor prognosis. The traditional view holds that the main mechanism of SAKI is the reduction of renal blood flow, inadequate renal perfusion, inflammatory response, and microcirculatory dysfunction caused by sepsis, which subsequently leads to ischemia and necrosis of renal tubular cells. Recent research findings indicate that processes such as autophagy and other forms of programmed cell death play an increasingly important role. Autophagy is a programmed intracellular degradation process and is a form of programmed cell death. Cells degrade their cytoplasmic components via lysosomes, breaking down and recycling intracellular constituents to meet their metabolic needs, maintain intracellular homeostasis, and renew organelles. During SAKI, autophagy plays a crucial protective role through various mechanisms, including regulating inflammation and immune responses, clearing damaged organelles, and maintaining stability in the intracellular environment. In recent years, the role of autophagy in the pathogenesis and treatment of SAKI has received widespread attention. Research has confirmed that various intracellular signaling pathways and signaling molecules targeting autophagy [such as mammalian target of rapamycin (mTOR) signaling pathway, AMP-activated protein kinase (AMPK) signaling pathway, nuclear factor-κB (NF-κB) signaling pathway, and Sirtuins (SIRT), autophagy associated factor Beclin-1, and Toll-like receptor (TLR)] are involved in the development of SAKI. Due to the complex pathogenesis of SAKI, current treatment strategies include fluid management, infection control, maintenance of internal environment balance, and renal replacement therapy; however, the mortality remains high. In recent years, it has been found that autophagy plays a critical protective role in sepsis-mediated AKI. As a result, an increasing number of drugs are being developed to alleviate SAKI by regulating autophagy. This article reviews the latest advances in the role of autophagy in the pathogenesis and treatment of SAKI, with the aim of providing insights for the development of new drugs for SAKI patients.
Humans ; Acute Kidney Injury/etiology* ; Autophagy ; Sepsis/complications* ; Signal Transduction

OBJECTIVE: To observe the neuroprotective effect of 6-shogaol (6-SH) in global cerebral ischemia/reperfusion injury (CIRI) following cardiac arrest (CA) and cardiopulmonary resuscitation (CPR) in rats. METHODS: Computer-aided molecular docking was used to determine whether 6-SH could spontaneously bind to death-associated protein kinase 1 (DAPK1). SPF-grade male SD rats were randomly divided into a sham group (n = 5), a CPR group (n = 7), and a CPR+6-SH group (n = 7). The CPR group and CPR+6-SH group were further divided into 12-, 24-, and 48-hour subgroups based on observation time points. A rat model of global CIRI after CA-CPR was established by asphyxiation. In the sham group, only tracheal and vascular intubation was performed without asphyxia and CPR induction. The CPR group was intraperitoneally injected with 1 mL of normal saline immediately after successful modeling. The CPR+6-SH group received an intraperitoneal injection of 20 mg/kg 6-SH (1 mL) immediately after successful modeling, followed by administration every 12 hours until the endpoint. Neurological Deficit Score (NDS) was recorded at each time point after modeling. After completion of observation at each time point, rats were anesthetized and sacrificed, and brain tissue specimens were collected. Histopathological changes of neurons were observed under light microscopy after hematoxylin-eosin (HE) staining. Ultrastructural changes of hippocampal neurons and autophagy were observed by transmission electron microscopy (TEM). Real-time quantitative polymerase chain reaction (RT-qPCR) was used to detect mRNA expression levels of DAPK1, vacuolar protein sorting 34 (VPS34), Beclin1, and microtubule-associated protein 1 light chain 3 (LC3) in brain tissues. Western blotting was used to detect protein expression levels of DAPK1, phosphorylated DAPK1 at serine 308 (p-DAPK1 ser308), VPS34, Beclin1, and LC3. Immunofluorescence was used to observe Beclin1 and LC3 expression in brain tissues under a fluorescence microscope. RESULTS: Molecular docking results indicated that 6-SH could spontaneously bind to DAPK1. Compared with the sham group, the NDS scores of the CPR group rats were significantly increased at all modeling time points; under light microscopy, disordered cell arrangement, widened intercellular spaces, and edema were observed in brain tissues, with pyknotic and necrotic nuclei in some areas; under TEM, mitochondria were markedly swollen with intact membranes, dissolved matrix, reduced or disappeared cristae, vacuolization, and increased autophagosomes. Compared with the CPR group, the NDS scores of the CPR+6-SH group rats were significantly decreased at all modeling time points; under light microscopy, local neuronal edema and widened perinuclear space were observed; under TEM, mitochondria were mostly mildly swollen with intact membranes, fewer autophagosomes, and alleviated injury. RT-qPCR results showed that compared with the sham group, mRNA expression levels of DAPK1, VPS34, Beclin1, and LC3 in brain tissues were significantly upregulated in all CPR subgroups, with the most pronounced changes at 24 hours. Compared with the CPR group, the CPR+6-SH group showed significantly lower mRNA expression of the above indicators at each time point [24 hours post-modeling (relative expression): DAPK1 mRNA: 3.41±0.68 vs. 4.48±0.62; VPS34 mRNA: 3.63±0.49 vs. 4.66±1.18; Beclin1 mRNA: 3.08±0.49 vs. 4.04±0.22; LC3 mRNA: 2.60±0.36 vs. 3.67±0.62; all P < 0.05]. Western blotting results showed that compared with the sham group, the protein expression levels of DAPK1, VPS34, Beclin1, and LC3 in all CPR subgroups were significantly increased, while the expression of p-DAPK1 ser308 was significantly decreased, with the most pronounced changes observed in the CPR 24-hour subgroup. Compared with the CPR group, the CPR+6-SH subgroups exhibited significantly reduced protein expression of DAPK1, VPS34, Beclin1, and LC3 [24-hour post-modeling: DAPK1/β-actin: 1.88±0.22 vs. 2.47±0.22; VPS34/β-actin: 2.55±0.06 vs. 3.46±0.05; Beclin1/β-actin: 2.12±0.03 vs. 2.87±0.03; LC3/β-actin: 2.03±0.24 vs. 3.17±0.23; all P < 0.05]. Conversely, the expression of p-DAPK1 ser308 was significantly upregulated in the CPR+6-SH group compared to the CPR group [24-hour post-modeling: p-DAPK1 ser308/β-actin: 0.40±0.02 vs. 0.20±0.07, P < 0.05]. Under the fluorescence microscope, fluorescence intensities of Beclin1 and LC3 in the CPR 24-hour group were significantly higher than those in the sham 24-hour group; compared with the CPR 24-hour group, the CPR+6-SH 24-hour group showed significantly reduced fluorescence intensities of Beclin1 and LC3. CONCLUSION 6-SH inhibited the expression of DAPK1, alleviated excessive autophagy after global CIRI following CA-CPR in rats, and exerted neuroprotective effects. The mechanism may be related to phosphorylation at the DAPK1 ser308 site.
Animals ; Rats, Sprague-Dawley ; Male ; Rats ; Cardiopulmonary Resuscitation ; Autophagy/drug effects* ; Heart Arrest/therapy* ; Death-Associated Protein Kinases/metabolism* ; Reperfusion Injury/metabolism* ; Disease Models, Animal ; Neuroprotective Agents/pharmacology* ; Brain Ischemia/metabolism*

OBJECTIVE: To observe the degree of myocardial cell injury and the changes in autophagy level in rats with myocardial ischemia/reperfusion (I/R) injury induced by cardiopulmonary bypass (CPB), and to explore the regulatory role of the long non-coding RNA-urothelial carcinoma antigen 1-microRNA-143-Notch1 axis (lncRNA-UCA1-miR-143-Notch1 axis) in myocardial I/R injury induced by CPB. METHODS: Healthy male Sprague-Dawley (SD) rats were randomly divided into the following groups using the random number method: Sham operation (Sham) group, myocardial I/R injury model group (model group), empty lentivirus group, lncRNA-UCA1 upregulation group, miR-143 downregulation group, and lncRNA-UCA1 upregulation+miR-143 upregulation group, with 9 rats in each group. The rat model of myocardial I/R injury induced by CPB was established by thoracotomy aortic ligation under cardiopulmonary bypass support; in the Sham group, only threading was performed without ligation, and other procedures were the same. Seventy-two hours before modeling, the lncRNA-UCA1 upregulated group was injected with 100 μL of myocardial tissue-specific adeno-associated virus (AAV) overexpression vector of lncRNA-UCA1 via tail vein, the miR-143 downregulated group was injected with 100 μL of AAV short hairpin RNA (shRNA) vector of miR-143 via tail vein, the lncRNA-UCA1 upregulation+miR-143 upregulation group was injected with 100 μL of myocardial tissue-AAV overexpression vector of lncRNA-UCA1 and 100 μL of AAV overexpression vector of miR-143 via tail vein, and the empty vector lentivirus group was injected with 100 μL of AAV empty vector (virus titers were 1×10⁹ TU/mL); the Sham group and the model group were injected with equal amounts of normal saline. The animals were euthanized 24 hours after intervention and cardiac tissue specimens were collected. After hematoxylin eosin (HE) staining, the damage of myocardial cells and the changes of muscle fiber tissue were observed under a light microscope; after dual staining with uranyl acetate and lead citrate, the ultrastructural damage of heart tissue was observed under a transmission electron microscopy; the expression of lncRNA-UCA1, miR-143, and Notch1 mRNA in myocardial tissue was detected by real-time fluorescence quantitative reverse transcription-polymerase chain reaction (RT-PCR); the expression of microtubule 1 light chain 3-II/I (LC3-II/I) and Notch1 protein in myocardial tissue was detected by Western blotting. RESULTS: Compared with the Sham group, the myocardial cells of rats in the model group were enlarged, the intercellular space increased, autophagosomes increased, the arrangement of myocardial fibers was disordered, mitochondrial proliferated and deformed. The expression levels of lncRNA-UCA1 and Notch1 mRNA, as well as the protein expression levels of LC3-II/I and Notch1 were significantly increased, while the expression level of miR-143 was significantly decreased. Compared with the model group, the degree of myocardial cell injury in the lncRNA-UCA1 upregulation group and miR-143 downregulation group was significantly alleviated, the expression levels of Notch1 mRNA, LC3-II/I, and Notch1 protein were significantly increased [Notch1 mRNA (2^-ΔΔCt): 2.66±0.24, 2.03±0.23 vs. 1.45±0.13, LC3-II/I: 2.10±0.21, 1.92±0.19 vs. 1.39±0.14, Notch1 protein (Notch1/GAPDH): 1.72±0.16, 1.57±0.16 vs. 1.34±0.13, all P < 0.05], and the expression level of miR-143 was significantly decreased (2^-ΔΔCt: 0.50±0.06, 0.52±0.06 vs.0.71±0.06, P < 0.05). The expression level of lncRNA-UCA1 in the lncRNA-UCA1 upregulated group was significantly higher than that in the model group (2^-ΔΔCt: 2.47±0.22 vs. 1.43±0.14, P < 0.05), while there was no significant difference in the miR-143 downregulation group compared with the model group (2^-ΔΔCt: 1.50±0.16 vs. 1.43±0.14, P > 0.05). There was no significant difference in the degree of myocardial cell injury in the empty load lentivirus group and the lncRNA-UCA1 upregulation+miR-143 upregulation group compared to the model group. There were no significant differences in the expression of miR-143, Notch1 mRNA, and the autophagy level in these two groups compared to the model group. The expression level of lncRNA-UCA1 in the lncRNA-UCA1 upregulation+miR-143 upregulation group was significantly higher than that in the model group (2^-ΔΔCt: 2.47±0.20 vs. 1.43±0.14, P < 0.05). CONCLUSIONS Autophagy is involved in the pathological process of myocardial I/R injury induced by CPB. The lncRNA-UCA1-microRNA-143-Notch1 axis may regulate the autophagy level to participate in the I/R injury process.
Animals ; MicroRNAs ; Rats, Sprague-Dawley ; RNA, Long Noncoding ; Male ; Myocardial Reperfusion Injury/etiology* ; Rats ; Cardiopulmonary Bypass/adverse effects* ; Receptor, Notch1/metabolism* ; Autophagy

OBJECTIVE: To explore the effects and mechanisms of the C-X-C motif chemokine ligand 12/C-X-C motif chemokine receptor 4 (CXCL12/CXCR4) signaling axis on apoptosis and autophagy in SH-SY5Y neuronal cells subjected to oxygen-glucose deprivation/reperfusion (OGD/R) model in vitro. METHODS: SH-SY5Y cells were divided into the following groups: OGD/R group and non-OGD/R group, with the OGD/R group subjected to OGD/R modeling and the non-OGD/R group receiving no treatment. Cells were also divided into CXCL12⁺ and CXCL12^- groups; the CXCL12⁺ group received 0.1 mg/L exogenous recombinant CXCL12 (rhCXCL12) at reoxygenation, while the CXCL12^- group did not. Another set of cells was divided into CXCL12+AMD3100 and CXCL12 groups; the CXCL12+AMD3100 group was pretreated with 2.5 mg/L AMD3100, a CXCR4 inhibitor, for 2 hours before OGD/R and received both 2.5 mg/L AMD3100 and 0.1 mg/L rhCXCL12 at reoxygenation, whereas the CXCL12 group received rhCXCL12 only. Additionally, cells were divided into small interfering RNA CXCR4 (siCXCR4) and small interfering RNA negative control (siNC) groups; the siCXCR4 group underwent CXCR4 knockdown before OGD/R modeling and received 0.1 mg/L rhCXCL12 at reoxygenation, while the siNC group, transfected with a negative control, received the same treatment. Protein expression of autophagy-related 16 (ATG16), microtubule-associated protein 1 light chain 3 (LC3), aquaporin-3 (AQP3), and CXCR4 was detected by Western blotting. Apoptosis rate and CXCR4 expression were measured by flow cytometry. RESULTS: Compared with the non-OGD/R group, the OGD/R group showed a significantly increased apoptosis rate and markedly decreased protein expression levels of ATG16, LC3, AQP3, and CXCR4 (all P < 0.05). CXCR4 fluorescent expression was also significantly reduced, suggesting that OGD/R simultaneously affects neuronal apoptosis and autophagy while inhibiting CXCR4 and AQP3 expression in SH-SY5Y cells. Compared with the CXCL12^- group, the CXCL12⁺ group exhibited no significant change in apoptosis rate but demonstrated significantly increased protein expression of ATG16, LC3, and AQP3 (ATG16/GAPDH: 1.21±0.10 vs. 1.00±0.00; LC3/β-actin: 1.22±0.10 vs. 1.00±0.00; AQP3/β-actin: 1.26±0.04 vs. 1.00±0.00; all P < 0.05). CXCR4 expression was also significantly enhanced (fluorescence intensity: 1.19±0.05 vs. 1.00±0.00, P < 0.05), indicating that CXCL12 may promote autophagy in OGD/R-injured SH-SY5Y cells via the CXCR4/AQP3 pathway. Compared with the CXCL12 group, the CXCL12+AMD3100 group showed no significant difference in apoptosis rate but significantly lower protein levels of ATG16 and LC3 (ATG16/GAPDH: 0.75±0.08 vs. 1.00±0.00; LC3/GAPDH: 0.86±0.07 vs. 1.00±0.00; both P < 0.05), suggesting that CXCL12 induces autophagy in OGD/R SH-SY5Y cells through CXCR4. Compared with the siNC group, the siCXCR4 group showed no significant change in apoptosis rate but significantly reduced protein expression of ATG16, LC3, AQP3, and CXCR4 (ATG16/GAPDH: 0.76±0.06 vs. 1.00±0.00; LC3/GAPDH: 0.79±0.11 vs. 1.00±0.00; AQP3/GAPDH: 0.81±0.05 vs. 1.00±0.00; CXCR4/GAPDH: 0.86±0.04 vs. 1.00±0.00; all P < 0.05), indicating that CXCR4 knockdown suppresses OGD/R-induced autophagy in SH-SY5Y cells likely via AQP3. CONCLUSIONS The CXCL12/CXCR4 signaling axis can regulate OGD/R-induced autophagy in SH-SY5Y cells through AQP3 without affecting apoptosis, indicating a role for this pathway in neuronal autophagy during cerebral ischemia/reperfusion injury.
Humans ; Receptors, CXCR4/metabolism* ; Chemokine CXCL12/metabolism* ; Autophagy ; Glucose/metabolism* ; Apoptosis ; Neurons/cytology* ; Oxygen/metabolism* ; Signal Transduction ; Cell Line, Tumor ; Cell Hypoxia ; Benzylamines ; Cyclams