ObjectiveTo investigate the effect of dexamethasone on mammalian target of rapamycin (mTOR) expression of astrocytes in hippocampus of rats with sepsis associated encephalopathy (SAE). MethodsTotally, 90 cases of 30-day-old male Wistar rats were randomly divided into sham-operation group (n=10) and cecal ligation and puncture (CLP) group (n=80). Models of rats with sepsis were established by CLP. At 12 hours after CLP, if rats appeared lower neurobehavioral scores, abnormal electroencephalogram (EEG) and somatosensory evoked potential (SEP), they were diagnosed with SAE. And then, they were randomly divided into non-treated group and dexamethasone group. Rats in the dexamethasone group were injected with dexamethasone (1 mg/kg) via tail vein every other day for a total of 3 times. The same dose of saline was used in the non-treated group. The neurobehavioral score was measured, SEP and EEG were examined in the age of 40 days, and then the rats were killed and the hippocampus was taken. Expressions of mTOR protein were measured by Western blot. The glial fibrillary acidic protein (GFAP) and mTOR were detected by immunofluorescence assay, and the number of positive cells was calculated by image analysis system software. ResultsSix of 80 CLP rats died in 12 hours after operation, and 28 of 74 rats were diagnosed as SAE because they appeared lower neurobehavioral scores, abnormal EEG and SEP at 12 hours after CLP. The incidence of SAE was 37.84% (28/74). In the age of 40 days, compared with non-treated group, neurobehavioral score of rats in the dexamethasone group was low, the amount of alpha waves in EEG reduced, delta waves increased, the amplitude of P1 waves in SEP was decreased, and the latencies of P1 and N1 waves were prolonged (P＜0.05). GFAP immunofluorescence staining showed astrocytic body and processes were small in the sham operation group. However, astrocytes in the non-treated group had large body and hypertrophic processes, and compared with the sham operation group, the number of these cells increased significantly (P＜0.05). Astrocytic body and processes were small in the dexamethasone group compared with the non-treated group, and the number of cells also decreased (P＜0.05). The mTOR positive astrocytes in the non-treated group were more than those in the sham operation group (P＜0.05). But mTOR positive astrocytes in the dexamethasone group were fewer than those in the non-treated group (P＜0.05). ConclusionsAstrocytes are activated in the hippocampus of rats with SAE. They show features of reactive hyperplasia, and the expression of mTOR is up-regulated, while dexamethasone can inhibit effects on these.
Objective To explore the effect and mechanism of rapamycin and deferoxamin on wound healing after ischemia and hypoxia. Methods The model of ischemia and hypoxia wound was made on the back of 40 SPF male adult Sprague Dawley rats, weight (300±20) g; they were randomly divided into 4 groups (n=10): the control group (group A), deferoxamine intervention group (group B), rapamycin intervention group (group C), and deferoxamine+rapamycin intervention group (group D). At 3, 6, and 9 days after model preparation, rats of groups A, B, C, and D were intra-peritoneally injected with normal saline, deferoxamin (10 mg/kg), rapamycin (3 mg/kg), deferoxamin (10 mg/kg)+rapamycin (3 mg/kg) respectively. The wound healing was observed and the healing time was recorded in each group; the wound healing tissue was harvested to test the mRNA and protein expressions of mammalian target of rapamycin (mTOR), hypoxia inducible factor 1α (HIF-1α), and vascular endothelial growth factor (VEGF) by real-time fluorescence quantitative PCR and Western blot at 2 days after wound healing. Results All rats survived to the end of the experiment, and wounds healed; the healing time of groups A, B, and D was significantly shorter than that of group C (P<0.05), but there was no significant difference between groups A, B, and D (P>0.05). Real-time fluorescence quantitative PCR showed that the expression of mTOR mRNA in groups C and D was significantly decreased when compared with the expressions in groups A and B (P<0.05); there was significant difference between groups A and B (P<0.05), but no significant difference between groups C and D (P>0.05). The expressions of HIF-1α mRNA and VEGF mRNA were signi-ficantly higher in groups B and D than groups A and C, and in group A than group C (P<0.05), but there was no signifi-cant difference between groups B and D (P>0.05). Western blot showed that the relative expressions of mTOR protein in groups C and D were significantly decreased when compared with the expressions in groups A and B (P<0.05), but there was no significant difference between groups C and D (P>0.05). The relative expressions of HIF-1α protein in groups A, B, and C were significantly increased when compared with expression in group D (P<0.05), but there was no significant difference between groups A, B, and C (P>0.05). The relative expression of VEGF protein were significantly lower in groups B, C, and D than group A, in group D than groups B and C, and in group C than group B (P<0.05). Conclusion Defe-roxamin can promote the wound healing of rats after ischemia and hypoxia, and the effect of rapamycin is opposite. It may be related to the existence of mTOR and HIF-1 signaling pathway in chronic ischemia-hypoxia wound.
Objective To review the possible mechanisms of the mammal ian target of rapamycin (mTOR) in theneuronal restoration process after nervous system injury. Methods The related l iterature on mTOR in the restoration ofnervous system injury was extensively reviewed and comprehensively analyzed. Results mTOR can integrate signals fromextracellular stress and then plays a critical role in the regulation of various cell biological processes, thus contributes to therestoration of nervous system injury. Conclusion Regulating the activity of mTOR signaling pathway in different aspects cancontribute to the restoration of nervous system injury via different mechanisms, especially in the stress-induced brain injury.mTOR may be a potential target for neuronal restoration mechanism after nervous system injury.
Objective To study the p-mammalian target of rapamyein(p-roTOR)expression and its prognostic significance in non-small cell lung cancer(NSCLC)．Methods Immunohistochemical staining of EnVision was applied to investigate the expression of p-roTOR in lung specimens from 59 cases with NSCLC and 10 cases with benign pulmonary diseases(3 pulmonary tuberculosises and 7 inflammatory pseudotumors 1．Results The positive rate of p-mTOR was 40．7％ in NSCLC which was significantly higher than that in the benign pulmonary diseases(x =6．237，P=0．013)．The expression of p-mTOR was closely correlated with age，sex and pTNM stage．Kaplan-Meire survival analysis revealed that the expression of p-mTOR was not correlated significantly with survival days(Log rank test P =0．055)．Conclusion P-mTOR might be a biomark for differential diagnosis of malignant lung disease，but has poor prognostic value．
ObjectiveTo investigate the mechanism of mTOR signaling pathway in bleomycin (BLM)-induced pulmonary fibrosis in mice.MethodsSixty C57BL/6 mice were randomly divided into a control group and a BLM group. Pulmonary fibrosis model was induced by single intratracheal instillation of bleomycin (2.5 mg/kg) in the BLM group. Similarly, 0.9% saline was instilled directly into the trachea in the control group. Then all mice were sacrificed at 21 days. The lungs were collected for morphometric analysis with HE and Masson staining. The degree of pulmonary fibrosis was evaluated with Ashcroft score. The activity of mTOR signaling pathway was measured by Western blot. The level of collagen1, collagen3 mRNA was assessed with quantitative real time PCR.ResultsThe thickening alveolar septa, accumulation of inflammatory cells, and fibrous obliteration in the BLM group were exhibited predominantly compared with the control group. There was a significant difference in Ashcroft score between the BLM group and the control (P<0.05). Also, the activity of mTOR signaling pathway was up-regulated and the expression of collagen1 mRNA and collagen3 mRNA was increased in the BLM group.ConclusionAberrant activation of mTOR signaling pathway aggravates the pulmonary fibrogenesis.
ObjectiveTo explore the involvement of miR-126 and the role of mammalian target of rapamycin (mTOR)/hypoxia-induced factor 1 α (HIF-1 α) pathway in regulating human umbilical cord mesenchymal stem cells (hUCMSCs) exosomes (Exo) on vascular endothelial growth factor (VEGF)-A levels in high glucose-induced human retinal vascular endothelial cells (HRECs). MethodsThe hREC was cultured in EGM-2-MV endothelial cell culture medium with 30 mmol/L glucose and placed in hypoxic cell incubator by 1% oxygen concentration. The cell model of high glucose and low oxygen was established. After modeling, divided HRECs into Exo group, phosphate buffer saline (PBS) group, PBS+anti-miR126 group, Exo+anti-miR126 group, PBS+anti-mTOR group, and PBS+anti-HIF-1 α group. High-glucose and hypoxia-induced hREC in the PBS and Exo groups were respectively co-cultured with PBS and 100 μg/ml hUCMSC Exo. PBS+anti-mTOR group, PBS+anti-HIF-1 α group: 500 nmol/L mTOR inhibitor ADZ2014, 25 μmol/L HIF-1 α inhibitor YC-1 pretreatment for hREC 12 h, and then co-culture with PBS after High-glucose and hypoxia-induced. PBS+anti-miR126 group, Exo+anti-miR126 group: miR-126 LNA power inhibitor probe was transfected with high glucose, and co-cultured with PBS and hUCMSC Exo 6 h after transfection. Real-time polymerase chain reaction (qPCR) measured miRNA-126 expression levels in PBS, and Exo groups for 0, 8, 16 and 24 h. After 24 hof co-culture, the levels of mTOR and HIF-1 α in the cells of PBS and Exo groups were detected by immunofluorescence, Western blot and qPCR, respectively. Western blot, qPCR detection of VEGF-A expression levels in cells of the PBS+anti-mTOR and PBS+anti-HIF-1 α groups. The expression of VE GF-A, mTOR, and HIF-1 α mRNA was measured in cells of PBS+anti-miR126 group and Exo+anti-miR126 group by qPCR. Comparison between two groups was performed by t-test; one-way ANOVA was used for comparison between multiple groups. ResultsAt 0, 8, 16 and 24 h, the relative mRNA expression of miR-126 gradually increased in the Exo group (F=95.900, P＜0.05). Compared with the PBS group, The mTOR, HIF-1 α protein (t=3.466, 6.804), mRNA in HRECs in the Exo group, VEGF-A mRNA expression (t=8.642, 7.897, 6.099) were all downregulated, the difference was statistically significant (P＜0.05). The relative expression level of VEGF-Aprotein (t=3.337, 7.380) and mRNA (t=8.515, 10.400) was decreased in HRECs of the anti-mTOR+PBS group and anti-HIF-1 α+PBS group, differences were statistically significant (P＜0.05). The relative expression of VEGF-A, mTOR, and HIF-1 α mRNA was significantly increased in the cells of the Exo+anti-miR126 group, the differences were all statistically significant (t=4.664, 6.136, 6.247; P＜0.05). ConclusionsmiR-126 plays a role in regulating the effect of hUCMSCs exosomes on VEGF-A levels in high glucose-induced HRECs via mTOR-HIF-1 α pathway.
Objective To review the role of mTOR signal pathway in chemo-resistance of gastric cancer. Methods Domestic and international publications related mTOR signal pathway in chemo-resistance of gastric cancer in recent years were collected and reviewed. Results mTOR was a central signaling molecule of mTOR signal pathway， which regulated key cellular processes such as cell growth， cell proliferation， cell metabolism， and angiogenesis. Signaling molecules of mTOR signal pathway were overexpressed in gastric cancer. Moreover， mTOR signal pathway might play an important role in chemo-resistance of gastric cancer， and tumor stem cells were involved in it too. Conclusion As mTOR signal pathway plays an important role in chemo-resistance of gastric cancer， the combination of mTOR inhibitors and chemotherapy drugs may overcome the chemo-resistance of gastric cancer.
Objective To explore the influence and mechanism of mechanistic target of rapamycin kinase (mTOR)/ receptor of advanced glycation end products (RAGE) pathway mediated-ferritinophagy on high glucose consumption promoting invasion and migration of colorectal cancer (CRC). Methods① Patients and tissue samples. Clinical data and tissues were collected from CRC patients underwent surgery and completed the dietary questionnaire in the Second Affiliated Hospital of Harbin Medical University from October 2022 to October 2023. Real-time quantitative reverse transcription PCR (qRT-PCR) was used to analyzed the expression of nuclear receptor coactivator 4 (NCOA4) and ferritin in CRC and para-carcinoma tissues. ② Cell culture and treatment. The HT29 and HCT116 cells were treated by RPMI1640 medium containing 0, 35, 70, 105, 140 mmol/L glucose, and cell counting kit-8 (CCK-8) and lactate dehydrogenase (LDH) activity analysis were performed to confirm 105 mmol/L glucose was the optimal concentration in the current study. Then the HT29 and HCT116 cells were randomly divided into: control group, glucose group; control group, glucose group, si-RAGE group, and glucose+si-RAGE group; control group, glucose group, rapamycin group, and glucose+rapamycin group. Untreated HT29 and HCT116 cells were considered as control group. The cells in glucose group were treated with 105 mmol/L glucose for 48 h. The CRC cells in the si-RAGE group were transfected with si-RAGE for 6 h. The CRC cells in the rapamycin group were treated with 10 nmol/L rapamycin for 48 h. The CRC cells in the glucose+si-RAGE group were treated with 105 mmol/L glucose for 48 h combination transfected with si-RAGE for 6 h. The CRC cells in the glucose+rapamycin group were treated with 105 mmol/L glucose for 48 h combination treated with 10 nmol/L rapamycin for 48 h. Then electron microscopy and Western blot, wound healing assay and transwell assay were exhibited, respectively. ③ Azoxymethane (AOM)-induced CRC rat model. The effects of glucose consumption on malignant behavior and ferritinophagy mediated by mTOR/RAGE pathway were evaluated in AOM-induced CRC rat models. A total of 16 rats were randomly divided into control group and glucose group, the CRC number was recorded and HE staining of CRC tissues was further performed. The expression of RAGE, mTOR, NCOA4, and ferritin in colorectal tissues of rats from each group was detected by RT-qPCR. Results① More lymphatic node metastasis and TNM Ⅲ/Ⅳ stages were observed in CRC patients from high glucose consumption group (P=0.004, P=0.004). Moreover, we confirmed that NCOA4 expression was significantly decreased (P<0.001) while ferritin was significantly increased (P<0.001) in CRC tissues especially in the CRC tissues from patients with positive lymph nodes metastasis. ② High glucose treatment significantly decreased autophagosomes in HT29 and HCT116 cells while si-RAGE transfection increased autophagic vacuoles compared to the control group. When compared with the glucose group, autophagosomes were increased in the glucose+si-RAGE group. Moreover, compared to the control group, the expressions of RAGE, p-mTOR, and ferritin were increased (P<0.001) while the expression of NCOA4 was decreased (P<0.001) in glucose group, but the expressions of RAGE, p-mTOR, and ferritin were decreased (P<0.001) while the expression of NCOA4 was increased (P<0.001) in the si-RAGE group; when compared with the glucose group, the expressions of RAGE, p-mTOR, and ferritin were downregulated (P<0.001) while the expression of NCOA4 was upregulated (P<0.001) in HT29 and HCT116 cells from the glucose+si-RAGE group. Compared to the control group, the HT29 and HCT116 cells in the glucose group performed enhanced wound scratch healing , migration and invasion viabilities (P<0.05); but the HT29 and HCT116 cells in the si-RAGE group performed impaired wound scratch healing, migration and invasion viabilities (P<0.05). When compared with the glucose group, the HT29 and HCT116 cells in the glucose+si-RAGE group performed impaired wound scratch healing, migration and invasion viabilities (P<0.05). ③ Rapamycin treatment significantly inhibited the expression of ferritin (P<0.05) but induced the expression of NCOA4 (P<0.05) compared to the control group. When compared with the glucose group, the expression of ferritin was downregulated (P<0.05) while the expression of NCOA4 was upregulated (P<0.05) in HT29 and HCT116 cells from the glucose+rapamycin group. Additionally, compared to the control group, rapamycin treatment performed inhibited effect on wound scratch healing, migration and invasion viabilities in the HT29 and HCT116 cells (P<0.05); while the HT29 and HCT116 cells in the glucose+rapamycin group performed impaired wound scratch healing, migration and invasion viabilities (P<0.05) when compared with the glucose group. ④ In the AOM induced CRC rat models, we found the more CRCs, aggravated cellular pleomorphism and upregulated expressions of RAGE, mTOR, ferritin (P<0.05) while downregulated expression of NCOA4 (P<0.05) in the glucose group than those of the control group. ConclusionHigh glucose consumption promote invasion and migration in CRC through suppressing ferritinophagy via activating the mTOR/RAGE pathway.