scholarly journals End-of-life targeted degradation of DAF-2 insulin/IGF-1 receptor promotes longevity free from growth-related pathologies

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Richard Venz ◽  
Tina Pekec ◽  
Iskra Katic ◽  
Rafal Ciosk ◽  
Collin Yvès Ewald
Keyword(s):  
Caenorhabditis Elegans ◽  
Growth Factor ◽  
Growth Retardation ◽  
Brood Size ◽  
Early Adulthood ◽  
Proof Of Concept ◽  
Time Points ◽  
Protein Levels ◽  
Egg Retention ◽  
Temporal And Spatial

Preferably, lifespan-extending therapies should work when applied late in life without causing undesired pathologies. Reducing insulin/insulin-like growth factor (IGF)-1 signaling (IIS) increases lifespan across species, but the effects of reduced IIS interventions in extreme geriatric ages remains unknown. Using the nematode Caenorhabditis elegans, we engineered the conditional depletion of the DAF-2/insulin/IGF-1 transmembrane receptor using an auxin-inducible degradation (AID) system. This allowed for the temporal and spatial reduction in DAF-2 protein levels at time points after which interventions such as RNAi become ineffective. Using this system, we found that AID-mediated depletion of DAF-2 protein surpasses the longevity of daf-2 mutants. Depletion of DAF-2 during early adulthood resulted in multiple adverse phenotypes, including growth retardation, germline shrinkage, egg retention, and reduced brood size. By contrast, AID-mediated depletion of DAF-2 post-reproduction, or specifically in the intestine in early adulthood, resulted in an extension of lifespan without these deleterious effects. Strikingly, at geriatric ages, when 75% of the population had died, AID-mediated depletion of DAF-2 protein resulted in a doubling in lifespan. Thus, we provide a proof-of-concept that even close to the end of an individual’s lifespan, it is possible to slow aging and promote longevity.

scholarly journals End-of-life targeted auxin-mediated degradation of DAF-2 Insulin/IGF-1 receptor promotes longevity free from growth-related pathologies

2021 ◽  
Author(s):  
Richard Venz ◽  
Tina Pekec ◽  
Iskra Katic ◽  
Rafal Ciosk ◽  
Collin Y Ewald
Keyword(s):  
End Of Life ◽  
Growth Retardation ◽  
Early Adulthood ◽  
Time Points ◽  
C Elegans ◽  
Protein Levels ◽  
Specific Targeting ◽  
Egg Retention ◽  
Median Lifespan ◽  
Temporal And Spatial

Preferably, lifespan-extending therapies should work when applied late in life without causing undesired pathologies. However, identifying lifespan-extending interventions that are effective late in life and which avoid undesired secondary pathologies remains elusive. Reducing Insulin/IGF-1 signaling (IIS) increases lifespan across species, but the effects of reduced IIS interventions in extreme geriatric ages remains unknown. Using the nematode C. elegans, we engineered the conditional depletion of the DAF-2/insulin/IGF-1 transmembrane receptor using an auxin-inducible degradation (AID) system that allows for the temporal and spatial reduction in DAF-2 protein levels at time points after which interventions such as RNAi may lose efficacy. Using this system, we found that AID-mediated depletion of DAF-2 protein efficiently extends animal lifespan. Depletion of DAF-2 during early adulthood resulted in multiple adverse phenotypes, including growth retardation, germline shrinkage, egg-retention, and reducing offspring. By contrast, however, AID-mediated depletion of DAF-2 specifically in the intestine resulted in an extension of lifespan without these deleterious effects. Importantly, AID-mediated depletion of DAF-2 protein in animals past their median lifespan allowed for an extension of lifespan without affecting growth or behavioral capacity. Thus, both late-in-life targeting and tissue-specific targeting of IIS minimize the deleterious effects typically seen with interventions that reduced IIS, suggesting potential therapeutic methods by which longevity and healthspan can be increased in even geriatric populations.

scholarly journals Caenorhabditis elegans Inositol 5-Phosphatase Homolog Negatively Regulates Inositol 1,4,5-Triphosphate Signaling in Ovulation

2002 ◽  
Vol 13 (5) ◽  
pp. 1641-1651 ◽  
Author(s):  
Yen Kim Bui ◽  
Paul W. Sternberg
Keyword(s):  
Caenorhabditis Elegans ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Signaling Pathway ◽  
Deletion Mutant ◽  
Egf Receptor ◽  
Type I ◽  
Spatial Expression ◽  
Epidermal Growth ◽  
Temporal And Spatial

Ovulation in Caenorhabditis elegans requires inositol 1,4,5-triphosphate (IP3) signaling activated by the epidermal growth factor (EGF)-receptor homolog LET-23. We generated a deletion mutant of a type I 5-phosphatase,ipp-5, and found a novel ovulation phenotype whereby the spermatheca hyperextends to engulf two oocytes per ovulation cycle. The temporal and spatial expression of IPP-5 is consistent with its proposed inhibition of IP3 signaling in the adult spermatheca. ipp-5 acts downstream oflet-23, and interacts withlet-23–mediated IP3 signaling pathway genes. We infer that IPP-5 negatively regulates IP3signaling to ensure proper spermathecal contraction.

PHOTACs Enable Optical Control of Protein Degradation

2019 ◽  
Author(s):  
Martin Reynders ◽  
Bryan Matsuura ◽  
Marleen Bérouti ◽  
Daniele Simoneschi ◽  
Antonio Marzio ◽  
...  
Keyword(s):  
Protein Degradation ◽  
E3 Ligase ◽  
Optical Control ◽  
Cellular Proteins ◽  
Bifunctional Molecules ◽  
Protein Levels ◽  
Lead Compounds ◽  
Subsequent Degradation ◽  
Temporal And Spatial ◽  
Precision Therapeutics

<p><i>PROTACs (proteolysis targeting chimeras) are bifunctional molecules that tag proteins for ubiquitylation by an E3 ligase complex and subsequent degradation by the proteasome. They have emerged as powerful tools to control the levels of specific cellular proteins and are on the verge of being clinically used. We now introduce photoswitchable PROTACs that can be activated with the temporal and spatial precision that light provides. These trifunctional molecules, which we named PHOTACs, consist of a ligand for an E3 ligase, a photoswitch, and a ligand for a protein of interest. We demonstrate this concept by using PHOTACs that target either BET family proteins (BRD2,3,4) or FKBP12. Our lead compounds display little or no activity in the dark but can be reversibly activated to varying degrees with different wavelengths of light. Our modular and generalizable approach provides a method for the optical control of protein levels with photopharmacology and could lead to new types of precision therapeutics that avoid undesired systemic toxicity.</i><b></b></p>

Long-term treadmill training ameliorates endothelium-dependent vasorelaxation mediated by insulin and insulin-like growth factor-1 in hypertension

2015 ◽  
Vol 119 (6) ◽  
pp. 663-669 ◽  
Author(s):  
Yi-Yuan Lin ◽  
Shin-Da Lee ◽  
Chia-Ting Su ◽  
Tsung-Lin Cheng ◽  
Ai-Lun Yang
Keyword(s):  
Growth Factor ◽  
Insulin Receptor ◽  
Treadmill Training ◽  
Control Group ◽  
Insulin Like Growth Factor ◽  
Hypertensive Rats ◽  
Protein Levels ◽  
Significant Difference ◽  
Nos Inhibitors

Dysfunction of insulin and insulin-like growth factor-1 (IGF-1) is associated with the pathophysiology of hypertension. The influence of long-term exercise on vascular dysfunction caused by hypertension remains unclear. We investigated whether long-term treadmill training improved insulin- and IGF-1-mediated vasorelaxation in hypertensive rats. Eight-week-old male spontaneously hypertensive rats (SHR) were randomly divided into sedentary and exercise (SHR-EX) groups. The SHR-EX group was trained on a treadmill for 60 min/day, 5 days/wk, for 8 wk. Wistar-Kyoto rats (WKY) were used as the normal control group. After training, aortic insulin- and IGF-1-mediated vasorelaxation was evaluated in organ baths. Additionally, the roles of phosphatidylinositol 3-kinase (PI3K), nitric oxide synthase (NOS), and aortic protein expression were examined in the three groups. Compared with sedentary SHR and WKY groups, insulin- and IGF-1-mediated vasorelaxation was significantly enhanced to a nearly normal level in the SHR-EX group. After endothelial denudation, blunted and comparable vasorelaxation was found among the three groups. Pretreatment with selective PI3K and NOS inhibitors attenuated insulin- and IGF-1-mediated vasorelaxation, and no significant difference was found among the three groups after the pretreatment. The aortic protein levels of the insulin receptor (IR), IGF-1 receptor (IGF-1R), insulin receptor substrate-1 (IRS-1), and endothelial NOS (eNOS) were also significantly increased in the SHR-EX group compared with the other two groups. These results suggested that treadmill training elicited the amelioration of endothelium-dependent insulin/IGF-1-mediated vasorelaxation partly via the increased activation of PI3K and NOS, as well as the enhancement of protein levels of IR, IGF-1R, IRS-1, and eNOS, in hypertension.

scholarly journals Reprimo (RPRM) Is a Novel Tumor Suppressor in Pituitary Tumors and Regulates Survival, Proliferation, and Tumorigenicity

Endocrinology ◽  
2012 ◽  
Vol 153 (7) ◽  
pp. 2963-2973 ◽  
Author(s):  
Mei Xu ◽  
Aaron J. Knox ◽  
Katherine A. Michaelis ◽  
Katja Kiseljak-Vassiliades ◽  
Bette K. Kleinschmidt-DeMasters ◽  
...  
Keyword(s):  
Growth Factor ◽  
Tumor Suppressor ◽  
Cellular Stress ◽  
Pituitary Tumors ◽  
Tumor Formation ◽  
Gh3 Cells ◽  
Pituitary Cells ◽  
Null Cell ◽  
Human Pituitary ◽  
Protein Levels

Reprimo (RPRM), initially identified as a downstream effector of p53-induced cell cycle arrest at G2/M, is a putative tumor suppressor silenced in some types of cancer. In microarrays, the RPRM transcript was repressed 26-fold in gonadotrope (null cell) human pituitary tumors compared with normal pituitary but in the absence of changes in p53. Inhibition of RPRM mRNA was confirmed by RT-PCR in all gonadotrope tumors, most GH samples, and variably in other tumor types. Human pituitary tumors showed no evidence of abnormal promoter hypermethylation as a mechanism of RPRM repression. RPRM stable expression in gonadotrope (LβT2) and GH (GH3) pituitary cells resulted in decreased rates of cell proliferation by 55 and 30%, respectively; however, RPRM reexpression did not alter G2/M transition. In addition, RPRM increased rates of apoptosis in response to growth factor deprivation as assessed by caspase-3 cleavage and nuclear condensation. Clonagenic assays showed a 5.3- and 3.7-fold suppression of colony growth in RPRM-overexpressing LβT2 and GH3 cells, respectively, supporting its role as a tumor suppressor. In cells stably expressing RPRM mRNA, protein levels were actively suppressed due to rapid degradation through ubiquitination and proteasomal targeting. Growth factor withdrawal, as a model of cellular stress, stabilized RPRM protein levels. Together these data suggest that RPRM is transiently up-regulated at a posttranscriptional level in times of cellular stress to restrict cell survival, proliferation, and tumor formation. When RPRM is silenced as in human pituitary tumors, unrestrained growth and tumor progression may occur.

Spaceflight modulates insulin-like growth factor binding proteins and glucocorticoid receptor in osteoblasts

1998 ◽  
Vol 85 (1) ◽  
pp. 139-147 ◽  
Author(s):  
Yasuhiro Kumei ◽  
Hitoyata Shimokawa ◽  
Hisako Katano ◽  
Hideo Akiyama ◽  
Masahiko Hirano ◽  
...  
Keyword(s):  
Growth Factor ◽  
Glucocorticoid Receptor ◽  
Space Shuttle ◽  
Mrna Levels ◽  
Insulin Like Growth Factor ◽  
Factor Binding ◽  
Dihydroxyvitamin D ◽  
Protein Levels ◽  
Glucocorticoid Receptor Mrna ◽  
Cellular Dna

Rat osteoblasts were cultured for 4 or 5 days during a Space Shuttle mission. After 20-h treatment with 1α,25-dihydroxyvitamin D3, conditioned media were harvested and cellular DNA and/or RNA were fixed on board. The insulin-like growth factor binding protein (IGF BP)-3 levels in the media were three- and tenfold higher than in ground controls on the fourth and fifth flight days, as quantitated by Western ligand blotting and radioimmunoassay, respectively. The increased IGF BP-3 protein levels correlated with two- to threefold elevation of IGF BP-3 mRNA levels, obtained by reverse transcription-polymerase chain reaction. The IGF BP-5 mRNA levels in flight cultures were 33–69% lower than in ground controls. The IGF BP-4 mRNA levels in flight cultures were 75% lower than in ground controls on the fifth day but were not different on the fourth day. The glucocorticoid receptor mRNA levels in flight cultures were increased by three- to eightfold on the fourth and fifth days compared with levels in ground controls. These data suggest potential mechanisms underlying spaceflight-induced osteopenia.

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