Journal: Cell reports

Article Title: Sarcosine Is Uniquely Modulated by Aging and Dietary Restriction in Rodents and Humans

doi: 10.1016/j.celrep.2018.09.065

Figure Lengend Snippet: (A) Mouse fibroblasts in culture (NIH 3T3 cells) expressing the tandem reporter mCherry-GFP-LC3 were exposed to the indicated concentrations of sarcosine for16 hr in the absence or presence of other autophagy inducers. Representative images of both controls and cells treated with 500 μM sarcosine in the presence or absence of serum are shown. (B) Quantification of autophagic flux (number of autophagosomes matured into autolysosomes) at the indicated sarcosine concentrations shows a dose responseto sarcosine (n > 2,500 cells). (C–E) Number of autophagic vacuoles (AVs; C), autophagosomes (APGs; D) and autolysosomes (AUTs; E) in cells treated with sarcosine (500 μM) show increased induction (vesicle count) and efficient clearance (AUT/APGs) of APGs (n > 2,500 cells). (F) Degradation of the autophagic cargo p62 in cells treated with increasing concentrations of sarcosine. Top: representative immunoblot. Bottom: quantification of the changes in p62 upon addition of lysosomal inhibitors ammonium chloride and leupeptin ammonium chloride and leupeptin (N/L) (n > 4 cells per condition). (G) A comparative analysis of several well-known inducers of autophagy with sarcosine. Sarcosine is more effective than metformin at inducing autophagy but less effective than rapamycin and spermidine (n > 2,500 cells). Quantification was done using high-content microscopy. Differences with untreated (“none”) are indicated. (H) Effect of the indicated treatments alone or in combination with 500 μM sarcosine on autophagic flux in cultured mouse fibroblasts. Several methods of autophagic induction were investigated, including oxidative damage (paraquat [PQ]), ER stress (thapsigargin [TG]) and lipotoxicity (oleic) in addition to serum-starved induction. Sarcosine showed an additive effect to serum starvation and paraquat, suggesting alternate mechanisms of activation, but not to thapsigargin or lipotoxicity (n > 2,500 cells). (I and J) Representative immunoblots (I) and densitometry analysis (J) in 3T3 cells demonstrate that sarcosine activates the mTOR signaling pathway in cells, but that this occurs in concert with Ulk and LAMP1 activation, suggesting that AMPK activity is also increased, thereby permitting increased autophagy in spite of mTOR activation. All results were obtained from a minimum of 3 independent experiments unless otherwise stated. Bars and lines indicate means ± SEMs (n = 3–4 per treatment). Significantly different from control: *p < 0.05, **p < 0.01, and ***p < 0.001.

Article Snippet: Human: NIH 3T3 mouse fibroblasts , Coriell Institute , N/A.

Techniques: Expressing, Western Blot, Microscopy, Cell Culture, Activation Assay, Activity Assay, Control

Journal: Cell reports

Article Title: Sarcosine Is Uniquely Modulated by Aging and Dietary Restriction in Rodents and Humans

doi: 10.1016/j.celrep.2018.09.065

Figure Lengend Snippet: (A) Autophagic flux increases in rat liver after short-term (10 days) dietary sarcosine feeding. Treatment with the inhibitors of lysosomal proteolysis (20 mM ammonium chloride and 100 μm leupeptin; N/L) revealed that degradation of LC3 and p62 in lysosomes was accelerated in the sarcosine-treated group. Representative immunoblot (left) and quantification of the levels and flux of LC3 and p62 (right) are both shown. n = 3 per group. (B) Effect of a short-term (10 days) dietary sarcosine treatment on the autophagic compartments in aged rat liver. Low-magnification images (left) and examples of the autophagic compartments more abundant in each of the groups (APGs in untreated and autolysosomes [AUTs] in sarcosine treated). Red arrows indicate AUTs, and yellow arrows indicate APGs. Quantification of the number of AVs, APGs, AUTs and lysosomes (LYSs) per section (left) and the percentage of AVs that display characteristics of APGs or AUTs (right) are shown. Data reveal improved maturation of APGs into AUTs after sarcosine treatment, which is indicative of increased autophagic flux (n = 20 sections from 3 different animals). More examples of each compartment are shown in Figure S7E. (C) Effect of old control and sarcosine-treated rat serum on autophagy. Heat-inactivated serum collected from old control or sarcosine-treated rats at 9 a.m. was added to the culture media of NIH 3T3 cells stably expressing the autophagy reporter mCherry-GFP-LC3. Cells were imaged, and the number per cell of AVs (mCherry+ vesicles), APGs (mCherry+ and GFP+ vesicles), and AUTs (ALs, mCherry+ GFP– vesicles) were quantified using high-content microscopy (n > 2,500 cells). Differences with controls (supplemented with serum from untreated rats) were significant at most serum concentrations tested. (D and E) Evaluation of signaling pathway activation in old rat liver following a short-term (10 days) dietary sarcosine treatment, as demonstrated by representative western blots (D) and the corresponding densitometry measurements (E), revealed that sarcosine increased pS6 in vivo, while a tendency toward increased activation of Akt and AMPK was observed (n = 8 per group). All results were obtained from a minimum of 3 independent experiments unless otherwise stated. Lines and bars indicate means ± SEMs. Significantly different from controls: *p < 0.05, **p < 0.01, and ***p < 0.001.

Article Snippet: Human: NIH 3T3 mouse fibroblasts , Coriell Institute , N/A.

Techniques: Western Blot, Control, Stable Transfection, Expressing, Microscopy, Activation Assay, In Vivo

Journal: Cell reports

Article Title: Sarcosine Is Uniquely Modulated by Aging and Dietary Restriction in Rodents and Humans

doi: 10.1016/j.celrep.2018.09.065

Figure Lengend Snippet: KEY RESOURCES TABLE

Article Snippet: Human: NIH 3T3 mouse fibroblasts , Coriell Institute , N/A.

Techniques: Virus, Recombinant, Protease Inhibitor, Staining, Western Blot, Fluorescence, Software, Modification, Microscopy, Imaging, Transmission Assay