BACKGROUND: T cell dysfunction, which includes exhaustion, anergy, and senescence, is a distinct T cell differentiation state that occurs after antigen exposure. Although T cell dysfunction has been a cornerstone of cancer immunotherapy, its potential in transplant research, while not yet as extensively explored, is attracting growing interest. Interferon regulatory factor 4 (IRF4) has been shown to play a pivotal role in inducing T cell dysfunction. METHODS: A novel ultra-low-dose combination of Trametinib and Rapamycin, targeting IRF4 inhibition, was employed to investigate T cell proliferation, apoptosis, cytokine secretion, expression of T-cell dysfunction-associated molecules, effects of mitogen-activated protein kinase (MAPK) and mammalian target of rapamycin (mTOR) signaling pathways, and allograft survival in both in vitro and BALB/c to C57BL/6 mouse cardiac transplantation models. RESULTS: In vitro , blockade of IRF4 in T cells effectively inhibited T cell proliferation, increased apoptosis, and significantly upregulated the expression of programmed cell death protein 1 (PD-1), Helios, CD160, and cytotoxic T lymphocyte-associated antigen (CTLA-4), markers of T cell dysfunction. Furthermore, it suppressed the secretion of pro-inflammatory cytokines interferon (IFN)-γ and interleukin (IL)-17. Combining ultra-low-dose Trametinib (0.1 mg·kg -1 ·day -1 ) and Rapamycin (0.1 mg·kg -1 ·day -1 ) demonstrably extended graft survival, with 4 out of 5 mice exceeding 100 days post-transplantation. Moreover, analysis of grafts at day 7 confirmed sustained IFN regulatory factor 4 (IRF4) inhibition, enhanced PD-1 expression, and suppressed IFN-γ secretion, reinforcing the in vivo efficacy of this IRF4-targeting approach. The combination of Trametinib and Rapamycin synergistically inhibited the MAPK and mTOR signaling network, leading to a more pronounced suppression of IRF4 expression. CONCLUSIONS Targeting IRF4, a key regulator of T cell dysfunction, presents a promising avenue for inducing transplant immune tolerance. In this study, we demonstrate that a novel ultra-low-dose combination of Trametinib and Rapamycin synergistically suppresses the MAPK and mTOR signaling network, leading to profound IRF4 inhibition, promoting allograft acceptance, and offering a potential new therapeutic strategy for improved transplant outcomes. However, further research is necessary to elucidate the underlying pharmacological mechanisms and facilitate translation to clinical practice.
Animals ; Mice ; Mice, Inbred BALB C ; Mice, Inbred C57BL ; Interferon Regulatory Factors/metabolism* ; Heart Transplantation/methods* ; T-Lymphocytes/immunology* ; Sirolimus/therapeutic use* ; Pyridones/therapeutic use* ; Graft Survival/drug effects* ; Pyrimidinones/therapeutic use* ; Cell Proliferation/drug effects* ; Apoptosis/drug effects* ; Male ; Signal Transduction/drug effects*

Objective To explore the role and mechanism of mammalian target of rapamycin (mTOR) in oxidized low-density lipoprotein (oxLDL)-induced ferroptosis in vascular smooth muscle cells (VSMCs). Methods A model of oxLDL-induced VSMC ferroptosis was established. VSMCs were co-treated with either the mTOR inhibitor rapamycin or the autophagy inducer carbonyl cyanide m-chlorophenylhydrazone (CCCP), followed by detection of autophagy and ferroptosis-related indexes. Quantitative real-time PCR and Western blot were used respectively to analyze the expression of mTOR, glutathione peroxidase 4 (GPX4), sequestosome 1 (p62), and microtubule-associated protein 1 light chain 3 (LC3). Flow cytometry was employed to assess VSMC death. C11 BODIPY fluorescent staining was used to measure cellular lipid peroxidation levels. Colorimetric assays were performed to determine the contents of malondialdehyde (MDA), ferrous ion (Fe²⁺) and glutathione (GSH). Results oxLDL significantly upregulated mTOR expression in VSMCs, while increasing p62 expression and reducing LC3 expression, thereby suppressing VSMC autophagy. Compared with oxLDL treatment alone, rapamycin co-treatment reversed oxLDL-induced VSMC ferroptosis, as characterized by reduced VSMC death, increased GPX4 expression and GSH contents, along with decreased MDA content, Fe²⁺ content and lipid peroxidation levels. Similarly, CCCP co-treatment activated autophagy characterized by reduced p62 expression and elevated LC3 expression, which subsequently alleviated oxLDL-induced ferroptosis, showing reduced VSMC death, increased GPX4 expressions and GSH contents, and decreased MDA content, Fe²⁺ content and lipid peroxidation levels. Moreover, mTOR inhibition by rapamycin significantly reversed the oxLDL-induced upregulation of p62 and downregulation of LC3. Conclusion mTOR may promote oxLDL-induced VSMC ferroptosis by suppressing autophagy.
Ferroptosis/drug effects* ; Lipoproteins, LDL/metabolism* ; TOR Serine-Threonine Kinases/physiology* ; Autophagy/drug effects* ; Muscle, Smooth, Vascular/metabolism* ; Animals ; Rats ; Myocytes, Smooth Muscle/cytology* ; Cells, Cultured ; Lipid Peroxidation/drug effects* ; Sequestosome-1 Protein/genetics* ; Phospholipid Hydroperoxide Glutathione Peroxidase/metabolism* ; Microtubule-Associated Proteins/genetics* ; Sirolimus/pharmacology*

OBJECTIVES: To investigate the effect of a variety of kidney-tonifying Chinese medicines on thymus regeneration after acute degeneration in mice. METHODS: Forty-eight 8-week-old male BALB/c mice were randomly divided into normal control group, model control group, negative control group, positive control group, the fructus of Cnidium monnieri (L.) Cuss. group, the fructus of Psoralea corylifolia (L.) group, the fructus of Rubus chingii Hu group, and the tuber onion seed group, with 6 mice in each group. Except for the normal control group, mice in the other groups received intraperitoneal injections of rapamycin (1 mg·kg^－1·d^－1) for 5 consecutive days followed by 14 h of starvation to induce acute thymus degeneration. After successful modeling, in treatment groups ethanol extract of the fructus of Cnidium monnieri (L.) Cuss. (0.78 g·kg^－1·d^－1), fructus of Psoralea corylifolia (L.) (0.39 g·kg^－1·d^－1), fructus of Rubus chingii Hu (0.78 g·kg^－1·d^－1) or the tuber onion seed(0.39 g·kg^－1·d^－1) was intraperitoneally injected once a day for 5 days; while the negative control group was given equal volume of normal saline, and the positive control group was given metformin (300 mg·kg^－1·d^－1). The grip strength was measured with a grip tester 2 h after the last administration. The pathological changes of thymus were observed by hematoxylin and eosin (HE) staining. The structure and distribution of thymic epithelial cells were observed by multiple immunofluorescence method. The proportion of T cell subsets in thymus and peripheral blood was analyzed by flow cytometry. The level of T cell receptor excision circles (TREC) in the genomic DNA of mouse spleen mononuclear cells was detected by quantitative polymerase chain reaction (PCR) for evaluation of thymic output function. The expression of thymus aging- and function-related factors in the thymus tissue were detected by quantitative reverse transcription PCR. The expression of cyclin-dependent kinase inhibitor 1A (p21) and tumor protein 53 (p53) were verified by immunohistochemistry. RESULTS: Rapamycin induced thymic atrophy and significantly reduced limb grip strength in mice (P<0.01). Compared with the negative control group, the limb grip strength of mice in the fructus of Psoralea corylifolia (L.) group, the fructus of Rubus chingii Hu group and the tuber onion seed group was significantly enhanced (all P<0.05), and the level of TREC in spleen of the mice in each administration group was reduced (all P<0.05). Among Chinese herb medicine-treatment groups, the recovery of thymus function and tissue structure in the tuber onion seed group was most obvious. Further study showed that compared with the negative control group, the proportion of CD4 single positive cells (CD3⁺TCR-β⁺CD4⁺CD8^－) in the thymus of the tuber onion seed group was significantly increased (P<0.01), and the proportion of CD3⁺CD28⁺ T cell and CD3⁺CD8⁺CD28⁺ T cell in peripheral blood was significantly increased (all P<0.01). The mRNA levels of IL-1α, IL-6, p21 and p53 in thymocytes were decreased (all P<0.05). The results of immunohistochemistry further confirmed the decrease in p21 and p53 expression. In normal mice, tuber onion seed was observed to enhance limb grip strength (P<0.01), while suppressing thymus output and change the distribution of T cell subsets, and there was no significant effect on thymus weight and the expression of Foxn1, SIRT1, p21, CXCL2 and PTMα. CONCLUSIONS The tuber onion seed and other kidney-tonifying traditional Chinese medicines can accelerate the regeneration process of mouse thymus after acute degeneration induced by rapamycin in mice, and the tuber onion seed exhibits the most pronounced therapeutic effect.
Animals ; Mice ; Male ; Mice, Inbred BALB C ; Thymus Gland/physiology* ; Drugs, Chinese Herbal/pharmacology* ; Sirolimus/adverse effects* ; Regeneration/drug effects*

Fibrodysplasia ossificans progressiva (FOP) is a rare genetic disorder characterized by congenital bilateral malformation of the large toe and progressive, extensive, and irreversible heterotopic ossification (HO) of soft tissues throughout the body, leading to severe disabilities. FOP is caused primarily by mutations in activin A receptor type 1 (ACVR1), also known as activin-like kinase 2 (ALK2), which encodes a receptor belonging to the bone morphogenetic protein (BMP) type I family. However, the continuous and complex process of HO in FOP is not yet fully understood, which has impeded the development of therapeutic drugs. Despite surgical removal of HO, which often results in recurrence and expansion of ossification, there is currently no definitive drug treatment available to completely prevent, halt, or reverse the progression of HO in FOP. Currently, researchers are intensively studying the pathogenesis of FOP at various stages and developing promising drug candidates, including saracatinib, palovarotene, and rapamycin. This review provides an overview of progress in understanding the mechanism of FOP and the development of therapeutic drugs, with the goal of providing insights for further research and the development of new treatment methods.
Myositis Ossificans/genetics* ; Humans ; Activin Receptors, Type I/genetics* ; Ossification, Heterotopic ; Mutation ; Sirolimus/therapeutic use* ; Quinolones/therapeutic use* ; Benzodioxoles/therapeutic use* ; Animals ; Quinazolines/therapeutic use*

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*

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

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.

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

BACKGROUND: The HELIOS stent is a sirolimus-eluting stent with a biodegradable polymer and titanium oxide film as the tie-layer. The study aimed to evaluate the safety and efficacy of HELIOS stent in a real-world setting. METHODS: The HELIOS registry is a prospective, multicenter, cohort study conducted at 38 centers across China between November 2018 and December 2019. A total of 3060 consecutive patients were enrolled after application of minimal inclusion and exclusion criteria. The primary endpoint was target lesion failure (TLF), defined as a composite of cardiac death, non-fatal target vessel myocardial infarction (MI), and clinically indicated target lesion revascularization (TLR) at 1-year follow-up. Kaplan-Meier methods were used to estimate the cumulative incidence of clinical events and construct survival curves. RESULTS: A total of 2998 (98.0%) patients completed the 1-year follow-up. The 1-year incidence of TLF was 3.10% (94/2998, 95% closed interval: 2.54-3.78%). The rates of cardiac death, non-fatal target vessel MI and clinically indicated TLR were 2.33% (70/2998), 0.20% (6/2998), and 0.70% (21/2998), respectively. The rate of stent thrombosis was 0.33% (10/2998). Age ≥60 years, diabetes mellitus, family history of coronary artery disease, acute myocardial infarction at admission, and device success were independent predictors of TLF at 1 year. CONCLUSION: The 1-year incidence rates of TLF and stent thrombosis were 3.10% and 0.33%, respectively, in patients treated with HELIOS stents. Our results provide clinical evidence for interventional cardiologists and policymakers to evaluate HELIOS stent. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov, NCT03916432.
Humans ; Middle Aged ; Sirolimus/therapeutic use* ; Drug-Eluting Stents/adverse effects* ; Prospective Studies ; Cohort Studies ; Treatment Outcome ; Risk Factors ; Time Factors ; Percutaneous Coronary Intervention/adverse effects* ; Cardiovascular Agents/therapeutic use* ; Coronary Artery Disease/therapy* ; Myocardial Infarction/etiology* ; Thrombosis/complications* ; Polymers ; Registries