Despina Komninou, Virginia L. Malloy, Jay A. Zimmerman, Raghu Sinha, John P. Richie Jr.
GeroScience. 2020 Feb
Dietary methionine restriction (MR) has been found to enhance longevity across many species. We hypothesized that MR might enhance longevity in part by delaying or inhibiting age-related disease processes. To this end, male Fischer 344 rats were fed control (CF, 0.86% methionine) or MR (0.17% methionine) diets throughout their life until sacrifice at approximately 30 months of age, and histopathology was performed to identify the incidence and progression of two important aging-related pathologies, namely, chronic progressive nephropathy (CPN) and testicular tumorigenesis. Although kidney pathology was observed in 87% CF rats and CPN in 62% of CF animals, no evidence of kidney disease was observed in MR rats. Consistent with the absence of renal pathology, urinary albumin levels were lower in the MR group compared to controls throughout the study, with over a six-fold difference between the groups at 30 months of age. Biomarkers associated with renal disease, namely, clusterin, cystatin C, and β-2 microglobulin, were reduced following 18 months of MR. A reduction in testicular tumor incidence from 88% in CF to 22% in MR rats was also observed. These results suggest that MR may lead to metabolic and cellular changes providing protection against age-related diseases.
Gao X, Sanderson SM, Dai Z, Reid MA, Cooper DE, Lu M, Richie JP Jr, Ciccarella A, Calcagnotto A, Mikhael PG, Mentch SJ, Liu J, Ables G, Kirsch DG, Hsu DS, Nichenametla SN, Locasale JW.
Nature. 2019 Aug;572(7769):397-401
Nutrition exerts considerable effects on health, and dietary interventions are commonly used to treat diseases of metabolic aetiology. Although cancer has a substantial metabolic component1, the principles that define whether nutrition may be used to influence outcomes of cancer are unclear2. Nevertheless, it is established that targeting metabolic pathways with pharmacological agents or radiation can sometimes lead to controlled therapeutic outcomes. By contrast, whether specific dietary interventions can influence the metabolic pathways that are targeted in standard cancer therapies is not known. Here we show that dietary restriction of the essential amino acid methionine-the reduction of which has anti-ageing and anti-obesogenic properties-influences cancer outcome, through controlled and reproducible changes to one-carbon metabolism. This pathway metabolizes methionine and is the target of a variety of cancer interventions that involve chemotherapy and radiation. Methionine restriction produced therapeutic responses in two patient-derived xenograft models of chemotherapy-resistant RAS-driven colorectal cancer, and in a mouse model of autochthonous soft-tissue sarcoma driven by a G12D mutation in KRAS and knockout of p53 (KrasG12D/+;Trp53-/-) that is resistant to radiation. Metabolomics revealed that the therapeutic mechanisms operate via tumour-cell-autonomous effects on flux through one-carbon metabolism that affects redox and nucleotide metabolism-and thus interact with the antimetabolite or radiation intervention. In a controlled and tolerated feeding study in humans, methionine restriction resulted in effects on systemic metabolism that were similar to those obtained in mice. These findings provide evidence that a targeted dietary manipulation can specifically affect tumour-cell metabolism to mediate broad aspects of cancer outcome.
Sebo ZL, Rendina-Ruedy E, Ables GP, Lindskog DM, Rodeheffer MS, Fazeli PK, Horowitz MC.
Endocr Rev. 2019 Oct 1;40(5):1187-1206
The presence of adipocytes in mammalian bone marrow (BM) has been recognized histologically for decades, yet, until recently, these cells have received little attention from the research community. Advancements in mouse transgenics and imaging methods, particularly in the last 10 years, have permitted more detailed examinations of marrow adipocytes than ever before and yielded data that show these cells are critical regulators of the BM microenvironment and whole-body metabolism. Indeed, marrow adipocytes are anatomically and functionally separate from brown, beige, and classic white adipocytes. Thus, areas of BM space populated by adipocytes can be considered distinct fat depots and are collectively referred to as marrow adipose tissue (MAT) in this review. In the proceeding text, we focus on the developmental origin and physiologic functions of MAT. We also discuss the signals that cause the accumulation and loss of marrow adipocytes and the ability of these cells to regulate other cell lineages in the BM. Last, we consider roles for MAT in human physiology and disease.