In the tumor microenvironment, metabolic reprogramming can impact metabolic characteristics of T cells, thus inducing immunosuppression to promote tumor immune escape. The mammalian target of rapamycin (mTOR) signaling pathway plays an important role in regulating diverse functions of various immune cells. This review mainly focuses on the molecular mechanism of mTOR signaling in regulating cellular energy metabolism process, and the activation status of mTOR signaling under different nutritional environments. In addition, it also summarizes the role of the mTOR signaling in regulatory T cell (Tregs) metabolism and function in current studies, and evaluates the potential of mTOR as a clinical immunotherapeutic target and its current application challenges.
Immunosuppression Therapy ; Metabolic Reprogramming ; Signal Transduction ; Sirolimus ; T-Lymphocytes, Regulatory ; TOR Serine-Threonine Kinases ; Humans

Acute hypobaric hypoxic brain damage is a potentially fatal high-altitude sickness. Autophagy plays a critical role in ischemic brain injury, but its role in hypobaric hypoxia (HH) remains unknown. Here we used an HH chamber to demonstrate that acute HH exposure impairs autophagic activity in both the early and late stages of the mouse brain, and is partially responsible for HH-induced oxidative stress, neuronal loss, and brain damage. The autophagic agonist rapamycin only promotes the initiation of autophagy. By proteome analysis, a screen showed that protein dynamin2 (DNM2) potentially regulates autophagic flux. Overexpression of DNM2 significantly increased the formation of autolysosomes, thus maintaining autophagic flux in combination with rapamycin. Furthermore, the enhancement of autophagic activity attenuated oxidative stress and neurological deficits after HH exposure. These results contribute to evidence supporting the conclusion that DNM2-mediated autophagic flux represents a new therapeutic target in HH-induced brain damage.
Mice ; Animals ; Hypoxia ; Oxidative Stress ; Autophagy ; Cognition ; Sirolimus/therapeutic use*

Klippel-Trenaunay syndrome (KTS) is a rare slow-flow congenital vascular disorder with an incidence of 1:100,000. 1 , 2 KTS is classically characterized by a clinical triad of capillary malformation, venous malformation, and bony or soft tissue hypertrophy. RAD50 and POLE genes act directly on deoxyribonucleicacid (DNA) and genome stability. Although distinct from the more studiedphosphatidylinositol-4,5-bisphosphate3-kinase catalytic subunit alpha (PIK3CA)gene, RAD50 and POLE genes coexist as a deficient gene in few vascular malformations and papillary thyroid carcinoma (PTC).

This is a case of a 7-month-old Filipino female patient clinically and radiologically diagnosed as KTS presenting with multiple capillary malformations and left limb length-girth discrepancies. Dermoscopy showed various vessel patterns in all affected areas. Soft tissue ultrasound and magnetic resonance imaging/angiography (MRI/MRA) of the left extremities revealed subcutaneous capillary malformations, hypertrophy of the subcutaneous structures and compartment muscles. Strong family history of PTC was elicited and genetic sequencing revealed detected RAD50 and POLE genes. She was treated using the mammalian target of rapamycin inhibitor sirolimus with careful monitoring of trough levels and radiographic tests. A significant outcome one year post-sirolimus revealed no abnormal vessels on ultrasound, a lesser degree of hypertrophy and capillary malformations were no longer appreciated in MRI/MRA of left extremities. Port-wine stains (PWS) and affected limbs showed a decrease in erythema and growth rate during the treatment period.

KTS detected with RAD50 and POLE genes successfully treated with sirolimus with trough-level monitoring. Radiographic evaluation and regular anthropometric assessment remain valuable in the diagnosis and monitoring.

Mammalian target of rapamycin (mTOR) controls cellular anabolism, and mTOR signaling is hyperactive in most cancer cells. As a result, inhibition of mTOR signaling benefits cancer patients. Rapamycin is a US Food and Drug Administration (FDA)-approved drug, a specific mTOR complex 1 (mTORC1) inhibitor, for the treatment of several different types of cancer. However, rapamycin is reported to inhibit cancer growth rather than induce apoptosis. Pyruvate dehydrogenase complex (PDHc) is the gatekeeper for mitochondrial pyruvate oxidation. PDHc inactivation has been observed in a number of cancer cells, and this alteration protects cancer cells from senescence and nicotinamide adenine dinucleotide (NAD^+‍) exhaustion. In this paper, we describe our finding that rapamycin treatment promotes pyruvate dehydrogenase E1 subunit alpha 1 (PDHA1) phosphorylation and leads to PDHc inactivation dependent on mTOR signaling inhibition in cells. This inactivation reduces the sensitivity of cancer cells' response to rapamycin. As a result, rebooting PDHc activity with dichloroacetic acid (DCA), a pyruvate dehydrogenase kinase (PDK) inhibitor, promotes cancer cells' susceptibility to rapamycin treatment in vitro and in vivo.
Humans ; Sirolimus/pharmacology* ; Dichloroacetic Acid/pharmacology* ; Pyruvate Dehydrogenase Complex ; TOR Serine-Threonine Kinases ; Mechanistic Target of Rapamycin Complex 1 ; Neoplasms/drug therapy*

Introduction: Cherry angiomas are a common type of acquired vascular proliferation of the skin which manifest as single or multiple bright red spots that usually appear on the trunk and arms. They are generally asymptomatic; patients may opt to remove the lesions for cosmetic reasons and prevention of bleeding. Conventionally, most cherry angiomas are treated with curettage, laser, and electrosurgery. Herein, we report a case of multiple cherry angiomas managed alternatively with oral sirolimus. Case: A 47-year-old Filipino female presented with a 10-month history of gradually enlarging multiple bright-red papules and pedunculated nodules with a propensity to spontaneously bleed on gentle manipulation involving the scalp and forehead. Clinicopathological correlation suggests a diagnosis of eruptive cherry angiomas. The patient was started on oral sirolimus, a mammalian target of rapamycin (mTOR) inhibitor. Conclusion We present a case of a patient with eruptive cherry angiomas who experienced significant decrease in size and bleeding with treatment of oral sirolimus with minimal adverse effects. For patients with eruptive cherry angiomas, especially with contraindicated comorbidities, first-line therapeutic option treatments with oral sirolimus can be beneficial.
sirolimus ; vascular malformation

Humans ; Sirolimus ; Cytarabine/therapeutic use* ; Erdheim-Chester Disease/drug therapy* ; Interferon-alpha/therapeutic use* ; Treatment Failure

OBJECTIVE: To investigate the effects of knocking down nucleostemin ( NS) combined with rapamycin (RAPA) on autophagy and apoptosis in HL-60 cells , and to explore its role in HL-60 cells . METHODS: The expression of NS protein was detected using Western blot , after transfection of HL-60 cells was achieved by the recombinant lentviral vector NS -RNAi-GV248 . Flow cytometry was used to detect changes in cells apoptosis after NS silencing/ rapamycin for 24 , 48 hours , and the expressions of NS , LC3 , p62 , BCL-2 and Bax proteins in cells were detected by Western blot. RESULTS: The expression of NS in HL-60 cells was successfully down-regulated by recombinant lentiviral vector. After treatment with rapamycin for 24 and 48 h , the apoptosis rate of cells in each group increased (P < 0.05) , and the apoptosis was more obvious at 48 hours . Compared with the NS silencing group or rapamycin group , after treated with NS down-regulation combined with rapamycin for 48 hours , the apoptosis of HL-60 cells was significantly increased ( P < 0.05 ) , LC3 -II/LC3 -I ratio was significantly increased ( P < 0.05 ) , p62 protein expression was significantly decreased (P < 0.05) , and BCL-2/Bax ratio was significantly decreased ( P < 0.05) . CONCLUSION NS down-regulation combined with rapamycin can enhance the apoptosis and autophagy of HL-60 cells , and the induction of apoptosis of HL-60 cells may be related to the expression of BCL-2 and Bax proteins .
Humans ; HL-60 Cells ; Sirolimus/pharmacology* ; bcl-2-Associated X Protein ; Autophagy ; Apoptosis

OBJECTIVE: To investigate the effect of emodin on high glucose (HG)-induced podocyte apoptosis and whether the potential anti-apoptotic mechanism of emodin is related to induction of adenosine-monophosphate-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR)-mediated autophagy in podocytes (MPC5 cells) in vitro. METHODS: MPC5 cells were treated with different concentrations of HG (2.5, 5, 10, 20, 40, 80 and 160 mmol/L), emodin (2, 4, 8 µ mol/L), or HG (40 mmol/L) and emodin (4 µ mol/L) with or without rapamycin (Rap, 100 nmol/L) and compound C (10 µ mol/L). The viability and apoptosis of MPC5 cells were detected using cell counting kit-8 (CCK-8) assay and flow cytometry analysis, respectively. The expression levels of cleaved caspase-3, autophagy marker light chain 3 (LC3) I/II, and AMPK/mTOR signaling pathway-related proteins were determined by Western blot. The changes of morphology and RFP-LC3 fluorescence were observed under microscopy. RESULTS: HG at 20, 40, 80 and 160 mmol/L dose-dependently induced cell apoptosis in MPC5 cells, whereas emodin (4 µ mol/L) significantly ameliorated HG-induced cell apoptosis and caspase-3 cleavage (P<0.01). Emodin (4 µ mol/L) significantly increased LC3-II protein expression levels and induced RFP-LC3-containing punctate structures in MPC5 cells (P<0.01). Furthermore, the protective effects of emodin were mimicked by rapamycin (100 nmol/L). Moreover, emodin increased the phosphorylation of AMPK and suppressed the phosphorylation of mTOR. The AMPK inhibitor compound C (10 µ mol/L) reversed emodin-induced autophagy activation. CONCLUSION Emodin ameliorated HG-induced apoptosis of MPC5 cells in vitro that involved induction of autophagy through the AMPK/mTOR signaling pathway, which might provide a potential therapeutic option for diabetic nephropathy.
Emodin/pharmacology* ; AMP-Activated Protein Kinases/metabolism* ; Podocytes ; Caspase 3/metabolism* ; TOR Serine-Threonine Kinases/metabolism* ; Signal Transduction ; Apoptosis ; Sirolimus/pharmacology* ; Glucose/metabolism* ; Autophagy

OBJECTIVES: The phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) pathway is one of the main signaling pathways related to autophagy. Autophagy plays a key role in the formation of silicosis fibrosis. The phenotypic transformation of lung fibroblasts into myofibroblasts is a hallmark of the transition from the inflammatory phase to the fibrotic phase in silicosis. This study aims to investigate whether the PI3K/Akt/mTOR pathway affects the phenotypic transformation of silicosis-induced lung fibroblasts into myofibroblasts via mediating macrophage autophagy. METHODS: The human monocytic leukemia cell line THP-1 cells were differentiated into macrophages by treating with 100 ng/mL of phorbol ester for 24 h. Macrophages were exposed to different concentrations (0, 25, 50, 100, 200, 400 μg/mL) and different times (0, 6, 12, 24, 48 h) of SiO₂ dust suspension. The survival rate of macrophages was measured by cell counting kit-8 (CCK-8) method. Enzyme linked immunosorbent assay (ELISA) was used to measure the contents of transforming growth factor-β1 (TGF-β1) and tumor necrosis factor-α (TNF-α) in the cell supernatant. The co-culture system of macrophages and HFL-1 cells was established by transwell. A blank control group, a SiO₂ group, a LY294002 group, a SC79 group, a LY294002+SiO₂ group, and a SC79+SiO₂ group were set up in this experiment. Macrophages in the LY294002+SiO₂ group were pretreated with LY294002 (PI3K inhibitor) for 18 hours, and macrophages in the SC79+SiO₂ group were pretreated with SC79 (Akt activator) for 24 hours, and then exposed to SiO₂ (100 μg/mL) dust suspension for 12 hours. The expression of microtubule-associated protein 1 light chain 3 (LC3) protein in macrophages was detected by the immunofluorescence method. The protein expressions of PI3K, Akt, mTOR, Beclin-1, LC3 in macrophages, and collagen III (Col III), α-smooth muscle actin (α-SMA), fibronectin (FN), matrix metalloproteinase-1 (MMP-1), tissue metalloproteinase inhibitor-1 (TIMP-1) in HFL-1 cells were measured by Western blotting. RESULTS: After the macrophages were exposed to SiO₂ dust suspension of different concentrations for 12 h, the survival rates of macrophages were gradually decreased with the increase of SiO₂ concentration. Compared with the 0 μg/mL group, the survival rates of macrophages in the 100, 200, and 400 μg/mL groups were significantly decreased, and the concentrations of TGF-β1 and TNF-α in the cell supernatant were obviously increased (all P<0.05). When 100 μg/mL SiO₂ dust suspension was applied to macrophages, the survival rates of macrophages were decreased with the prolonged exposure time. Compared with the 0 h group, the survival rates of macrophages were significantly decreased (all P<0.05), the concentrations of TGF-β1 and TNF-α in the cell supernatant were significantly increased, and the protein expression levels of Beclin-1 and LC3II were increased markedly in the 6, 12, 24, and 48 h groups (all P<0.05). Immunofluorescence results demonstrated that after exposure to SiO₂ (100 μg/mL) dust for 12 h, LC3 exhibited punctate aggregation and significantly higher fluorescence intensity compared to the blank control group (P<0.05). Compared with the blank control group, the protein expressions of Col III, FN, α-SMA, MMP-1, and TIMP-1 in HFL-1 cells were up-regulated in the SiO₂ group (all P<0.05). Compared with the SiO₂ group, the protein expressions of PI3K, Akt, and mTOR were down-regulated and the protein expressions of LC3II and Beclin-1 were up-regulated in macrophages (all P<0.05), the contents of TNF-α and TGF-β1 in the cell supernatant were decreased (both P<0.01), and the protein expressions of Col III, FN, α-SMA, MMP-1, and TIMP-1 in HFL-1 cells were down-regulated (all P<0.05) in the LY294002+SiO₂ group. Compared with the SiO₂ group, the protein expressions of PI3K, Akt, and mTOR were up-regulated and the protein expressions of LC3II and Beclin-1 were down-regulated in macrophages (all P<0.05), the contents of TNF-α and TGF-β1 in the cell supernatant were increased (both P<0.01), and the protein expressions of Col III, FN, α-SMA, MMP-1, and TIMP-1 in HFL-1 cells were up-regulated (all P<0.05) in the SC79+SiO₂ group. CONCLUSIONS Silica dust exposure inhibits the PI3K/Akt/mTOR pathway, increases autophagy and concentration of inflammatory factors in macrophages, and promotes the phenotype transformation of HFL-1 cells into myofibroblasts. The regulation of the PI3K/Akt/mTOR pathway can affect the autophagy induction and the concentration of inflammatory factors of macrophages by silica dust exposure, and then affect the phenotype transformation of HFL-1 cells into myofibroblasts induced by silica dust exposure.
Humans ; Proto-Oncogene Proteins c-akt/metabolism* ; Transforming Growth Factor beta1/metabolism* ; Silicon Dioxide/metabolism* ; Phosphatidylinositol 3-Kinases/metabolism* ; Matrix Metalloproteinase 1/metabolism* ; Tissue Inhibitor of Metalloproteinase-1 ; Sirolimus ; Beclin-1/metabolism* ; Tumor Necrosis Factor-alpha/metabolism* ; Dust ; TOR Serine-Threonine Kinases/metabolism* ; Lung/metabolism* ; Fibroblasts/metabolism* ; Silicosis/metabolism* ; Macrophages/metabolism* ; Autophagy

This paper aimed to investigate the role and potential mechanism of p53 on primordial follicle activation. Firstly, the p53 mRNA expression in the ovary of neonatal mice at 3, 5, 7 and 9 days post-partum (dpp) and the subcellular localization of p53 were detected to confirm the expression pattern of p53. Secondly, 2 dpp and 3 dpp ovaries were cultured with p53 inhibitor Pifithrin-μ (PFT-μ, 5 μmol/L) or equal volume of dimethyl sulfoxide for 3 days. The function of p53 in primordial follicle activation was determined by hematoxylin staining and whole ovary follicle counting. The proliferation of cell was detected by immunohistochemistry. The relative mRNA levels and protein levels of the key molecules involved in the classical pathways associated with the growing follicles were examined by immunofluorescence staining, Western blot and real-time PCR, respectively. Finally, rapamycin (RAP) was used to intervene the mTOR signaling pathway, and ovaries were divided into four groups: Control, RAP (1 μmol/L), PFT-μ (5 μmol/L), PFT-μ (5 μmol/L) + RAP (1 μmol/L) groups. The number of follicles in each group was determined by hematoxylin staining and whole ovary follicle counting. The results showed that the expression of p53 mRNA was decreased with the activation of primordial follicles in physiological condition. p53 was expressed in granulosa cells and oocyte cytoplasm of the primordial follicles and growing follicles, and the expression of p53 in the primordial follicles was higher than that in the growing follicles. Inhibition of p53 promoted follicle activation and reduced the primordial follicle reserve. Inhibition of p53 promoted the proliferation of the granulosa cells and oocytes. The mRNA and protein expression levels of key molecules in the PI3K/AKT signaling pathway including AKT, PTEN, and FOXO3a were not significantly changed after PFT-μ treatment, while the expression of RPS6/p-RPS6, the downstream effectors of the mTOR signaling pathway, was upregulated. Inhibition of both p53 and mTOR blocked p53 inhibition-induced primordial follicle activation. Collectively, these findings suggest that p53 may inhibit primordial follicle activation through the mTOR signaling pathway to maintain the primordial follicle reserve.
Female ; Animals ; Mice ; Tumor Suppressor Protein p53/metabolism* ; Proto-Oncogene Proteins c-akt/metabolism* ; Phosphatidylinositol 3-Kinases/metabolism* ; Hematoxylin ; Signal Transduction/physiology* ; TOR Serine-Threonine Kinases ; Sirolimus ; RNA, Messenger