Rapamycin in preventive (very low) doses

Low-dose rapamycin prevents Ang-II-induced toxicity in Leydig cells and testicular dysfunction in hypertensive SHR model

Hypertension is a common chronic cardiovascular disease reported among both men and women. Hypertension in males affects the testis and reproduction function; however, the pathogenesis is poorly understood. Rapamycin has been reported to have a variety of beneficial pharmacological effects; however, high-doses rapamycin does have side effects such as immunosuppression. The present study investigates whether low-dose rapamycin can reduce the damage caused by hypertension to the testis of spontaneously hypertensive rats (SHRs) and further examines molecular mechanism of low-dose rapamycin in preventing testicular toxicity induced by angiotensin II (Ang II). Low rapamycin dose restores the testicle size, histological alterations, 3β-hydroxysteroid dehydrogenase (3β-HSD) expression, and prevents apoptosis in SHR rats. Ang II downregulates angiotensin-converting enzyme-2 (ACE2) expression through AT1R, p-ERK, and MAS receptor in LC-540 Leydig cells in a dose-dependent manner. Low doses of rapamycin effectively upregulate steroidogenic enzymes, steroidogenic acute regulatory protein and 3β-HSD expression in Leydig cells. Rapamycin upregulates ACE2 expression through p-PKAc and p-PI3k in Ang II-treated cells. Further, rapamycin curbs mitochondrial superoxide generation and depleted mitochondrial membrane potential induced by Ang II through activation of Nrf2-mediated Gpx4 and superoxide dismutase 2 expression. Our results revealed the involvement of ACE2, AT1R, AT2R, PKAc, and oxidative stress in Ang-II-induced testicular toxicity, suggesting low-dose rapamycin could be a potential therapeutic candidate to attenuate testicular toxicity.

The autophagy-activating kinase ULK1 mediates clearance of free α-globin in β-thalassemia

In β-thalassemia, accumulated free α-globin forms intracellular precipitates that impair erythroid cell maturation and viability. Protein quality control systems mitigate β-thalassemia pathophysiology by degrading toxic free α-globin, although the associated mechanisms are poorly understood. We show that loss of the autophagy-activating Unc-51-like kinase 1 (Ulk1) gene in β-thalassemic mice reduces autophagic clearance of α-globin in red blood cell precursors and exacerbates disease phenotypes, whereas inactivation of the canonical autophagy-related 5 (Atg5) gene has relatively minor effects. Systemic treatment with the mTORC1 inhibitor rapamycin reduces α-globin precipitates and lessens pathologies in β-thalassemic mice via an ULK1-dependent pathway. Similarly, rapamycin reduces free α-globin accumulation in erythroblasts derived from CD34⁺ cells of β-thalassemic individuals. Our findings define a drug-regulatable pathway for ameliorating β-thalassemia.

From rapalogs to anti-aging formula

Inhibitors of mTOR, including clinically available rapalogs such as rapamycin (Sirolimus) and Everolimus, are gerosuppressants, which suppress cellular senescence. Rapamycin slows aging and extends life span in a variety of species from worm to mammals. Rapalogs can prevent age-related diseases, including cancer, atherosclerosis, obesity, neurodegeneration and retinopathy and potentially rejuvenate stem cells, immunity and metabolism. Here, I further suggest how rapamycin can be combined with metformin, inhibitors of angiotensin II signaling (Losartan, Lisinopril), statins (simvastatin, atorvastatin), propranolol, aspirin and a PDE5 inhibitor. Rational combinations of these drugs with physical exercise and an anti-aging diet (Koschei formula) can maximize their anti-aging effects and decrease side effects.

The Role of the Mammalian Target of Rapamycin (mTOR) in Pulmonary Fibrosis

The phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR)-dependent pathway is one of the most integral pathways linked to cell metabolism, proliferation, differentiation, and survival. This pathway is dysregulated in a variety of diseases, including neoplasia, immune-mediated diseases, and fibroproliferative diseases such as pulmonary fibrosis. The mTOR kinase is frequently referred to as the master regulator of this pathway. Alterations in mTOR signaling are closely associated with dysregulation of autophagy, inflammation, and cell growth and survival, leading to the development of lung fibrosis. Inhibitors of mTOR have been widely studied in cancer therapy, as they may sensitize cancer cells to radiation therapy. Studies also suggest that mTOR inhibitors are promising modulators of fibroproliferative diseases such as idiopathic pulmonary fibrosis (IPF) and radiation-induced pulmonary fibrosis (RIPF). Therefore, mTOR represents an attractive and unique therapeutic target in pulmonary fibrosis. In this review, we discuss the pathological role of mTOR kinase in pulmonary fibrosis and examine how mTOR inhibitors may mitigate fibrotic progression.

Identification of Salvia haenkei as gerosuppressant agent by using an integrated senescence-screening assay

Cellular senescence is a stable cell cycle arrest that is the causative process of aging. The PI3K/AKT/mTOR pathway is implicated in the control of cellular senescence and inhibitors of this pathway have been successfully used for life span prolongation experiments in mammals. PTEN is the major regulator of the PI3K/AKT/mTOR pathway and loss of PTEN promotes a senescence response termed PICS. Here we report a novel-screening assay, for the identification of compounds that block different types of senescence response. By testing a library of more than 3000 natural and chemical compounds in PTEN deficient cells we have found that an extract from Salvia haenkei (SH), a native plant of Bolivia is a potent inhibitor of PICS. SH also decreases replicative and UV-mediated senescence in human primary fibroblasts and in a model of in vitro reconstructed human epidermis. Mechanistically, SH treatment affects senescence driven by UV by interfering with IL1-α signalling. Pre-clinical and clinical testing of this extract by performing toxicity and irritability evaluation in vitro also demonstrate the safety of SH extract for clinical use as anti-aging skin treatment.

Calorie restriction effects on circadian rhythms in gene expression are sex dependent

The rhythms in the expression of circadian clock genes are affected by calorie restriction (CR), a dietary paradigm known to increase lifespan. Many physiological effects of CR differ between males and females; here we investigated if the sex of animals affects the CR induced changes in the circadian rhythms. The liver expression of some circadian clock genes such as Bmal1 and three Periods (Per1, Per2 and Per3) and the effect of CR on the expression of these genes were sex independent, while the expression of Rev-Erb alpha, Ror gamma and both Cryptochome (Cry1 and Cry2) genes was different between males and females. The effect of CR on Rev-Erb alpha, Ror gamma and Cry1 gene expression was sex dependent. The expression and the effects of CR were sex-specific for several genes previously reported to be regulated by CR: Fmo3, Mup4, Serpina12 and Cyp4a12, while the expression of Cyp4a14a was sex independent. IGF signaling plays an important role in aging and CR effects. Igf-1 expression is regulated by CR and by the circadian clock, we found that rhythms in Igf-1 expression have sexual dimorphism. Our data provide molecular evidence that the sex of animals is an important modulator of circadian rhythms in gene expression and their response to CR.

Mammalian Target of Rapamycin Inhibition With Rapamycin Mitigates Radiation-Induced Pulmonary Fibrosis in a Murine Model

PURPOSE

Radiation-induced pulmonary fibrosis (RIPF) is a late toxicity of therapeutic radiation. Signaling of the mammalian target of rapamycin drives several processes implicated in RIPF, including inflammatory cytokine production, fibroblast proliferation, and epithelial senescence. We sought to determine if mammalian target of rapamycin inhibition with rapamycin would mitigate RIPF.

METHODS AND MATERIALS

C57BL/6NCr mice received a diet formulated with rapamycin (14 mg/kg food) or a control diet 2 days before and continuing for 16 weeks after exposure to 5 daily fractions of 6 Gy of thoracic irradiation. Fibrosis was assessed with Masson trichrome staining and hydroxyproline assay. Cytokine expression was evaluated by quantitative real-time polymerase chain reaction. Senescence was assessed by staining for β-galactosidase activity.

RESULTS

Administration of rapamycin extended the median survival of irradiated mice compared with the control diet from 116 days to 156 days (P=.006, log-rank test). Treatment with rapamycin reduced hydroxyproline content compared with the control diet (irradiation plus vehicle, 45.9 ± 11.8 μg per lung; irradiation plus rapamycin, 21.4 ± 6.0 μg per lung; P=.001) and reduced visible fibrotic foci. Rapamycin treatment attenuated interleukin 1β and transforming growth factor β induction in irradiated lungs compared with the control diet. Type II pneumocyte senescence after irradiation was reduced with rapamycin treatment at 16 weeks (3-fold reduction at 16 weeks, P<.001).

CONCLUSIONS

Rapamycin protected against RIPF in a murine model. Rapamycin treatment reduced inflammatory cytokine expression, extracellular matrix production, and senescence in type II pneumocytes.

Rejuvenating immunity: "anti-aging drug today" eight years later

The 2014 year ended with celebration: Everolimus, a rapamycin analog, was shown to improve immunity in old humans, heralding ‘a turning point’ in research and new era in human quest for immortality. Yet, this turning point was predicted a decade ago. But what will cause human death, when aging will be abolished?

Rapatar, a nanoformulation of rapamycin, decreases chemically-induced benign prostate hyperplasia in rats

Benign prostatic hyperplasia (BPH) is the most common age-related disease in men. Here we tested the efficacy of Rapatar, a micellar nanoformulation of rapamycin, in two rat models of BPH: testosterone-induced and sulpiride-induced hyperplasia in ventral lobes and lateral/dorsal lobes, respectively. We found that Rapatar prevented hypertrophic and hyperplastic abnormalities and degenerative alterations in both BPH models. Rapatar normalized weight of the lateral lobes in sulpiride-induced BPH, the most relevant animal model of human BPH. Unlike Finasteride, a standard therapy of BPH, Rapatar reduced inflammation caused by sulpiride. No obvious side effects of Rapatar were detected. Our data provide a rationale for clinical trials of Rapatar in patients suffering from BPH.

Serum level of hepatocyte growth factor is a novel marker of predicting the outcome and resistance to the treatment with trastuzumab in HER2-positive patients with metastatic gastric cancer

HER2-overexpression in tumor tissue is observed in 6 to 23% of advanced gastric cancer (GC) cases, and trastuzumab is an active molecular drug for these patients. There are no data available on whether serum levels of ligands are associated with the response and resistance to trastuzumab in HER2-positive patients with metastatic GC. HER2 screening of 502 patients with advanced gastric cancer was performed in our institution. Among these patients, 84 patients (16.8%) were diagnosed as HER2-positive, and those who were treated with trastuzumab and met the inclusion criteria were enrolled in the present study. Serum levels of ligands that affect the HER2 signal pathway were measured by an enzyme-linked immunosorbent assay. Forty-six HER2-positive patients were enrolled in this study, and 26 patients (56.5%) achieved a partial response to treatment with trastuzumab. Among several ligands, the serum level of hepatocyte growth factor (HGF) was significantly lower in responders compared with that in non-responders (p = 0.014). Multivariate analyses showed that a high level of serum HGF was a poor prognostic factor for overall survival (OS) compared with low levels of HGF (adjusted HR: 3.857, 95% CI: 1.309-11.361, p = 0.014). Among 25 patients without initial disease progression on the treatment with trastuzumab, the mean value of serum HGF at disease progression was significantly higher than that at pre-treatment (p = 0.041). As novel findings, our study indicated that serum level of HGF was associated with tumor shrinkage and time to progression of trastuzumab in HER2-positive patients with metastatic GC.

Gerosuppression in confluent cells

The most physiological type of cell cycle arrest - namely, contact inhibition in dense culture - is the least densely studied. Despite cell cycle arrest, confluent cells do not become senescent. We recently described that mTOR (target of rapamycin) is inactive in contact-inhibited cells. Therefore, conversion from reversible arrest to senescence (geroconversion) is suppressed. I this Perspective, we further extended the gerosuppression model. While causing senescence in regular cell density, etoposide failed to cause senescence in contact-inhibited cells. A transient reactivation of mTOR favored geroconversion in etoposide-treated confluent cells. Like p21, p16 did not cause senescence in high cell density. We discuss that suppression of geroconversion in confluent and contact-inhibited cultures mimics gerosuppression in the organism. We confirmed that levels of p-S6 were low in murine tissues in the organism compared with mouse embryonic fibroblasts in cell culture, whereas p-Akt was reciprocally high in the organism.

Comparison of rapamycin schedules in mice on high-fat diet

At a wide range of doses, rapamycin extends life span in mice. It was shown that intraperitoneal injections (i.p.) of rapamycin prevent weight gain in mice on high-fat diet (HFD). We further investigated the effect of rapamycin on weight gain in female C57BL/6 mice on HFD started at the age of 7.5 months. By the age of 16 and 23 months, mice on HFD weighed significantly more (52 vs 33 g; p = 0.0001 and 70 vs 38 g; p < 0.0001, respectively) than mice on low fat diet (LFD). The i.p. administration of 1.5 mg/kg rapamycin, 3 times a week every other week, completely prevented weight gain, whereas administration of rapamycin by oral gavash did not. Rapamycin given in the drinking water slightly decreased weight gain by the age of 23 months. In addition, metabolic parameters were evaluated at the age of 16 and 23 months, 6 and 13 days after last rapamycin administration, respectively. Plasma leptin levels strongly correlated with body weight, (P < 0.0001, r=0.86), suggesting that the difference in weight was due to fat tissue mass. Levels of insulin, glucose, triglycerides and IGF1 were not statistically different in all groups, indicating that these courses of rapamycin treatment did not impair metabolic parameters at least after rapamycin discontinuation. Despite rapamycin discontinuation, cardiac levels of phospho-S6 and pAKT(S473) were low in the i.p.-treated group. This continuous effect of rapamycin can be explained by prevention of obesity in the i.p. group. We conclude that intermittent i.p. administration of rapamycin prevents weight gain without causing gross metabolic abnormalities. Intermittent gavash administration minimally affected weight gain. Potential clinical applications are discussed.

Koschei the immortal and anti-aging drugs

In Slavic folklore, Koschei the Immortal was bony, thin and lean. Was his condition caused by severe calorie restriction (CR)? CR deactivates the target of rapamycin pathway and slows down aging. But the life-extending effect of severe CR is limited by starvation. What if Koschei's anti-aging formula included rapamycin? And was rapamycin (or another rapalog) combined with commonly available drugs such as metformin, aspirin, propranolol, angiotensin II receptor blockers and angiotensin-converting enzyme inhibitors.