Comparison of Local Metabolic Changes in Diabetic Rodent Kidneys Using Mass Spectrometry Imaging

Investigation of metabolite alterations in the kidneys of methionine-choline-deficient mouse by mass spectrometry imaging

Methionine and choline both are essential nutrients which are needed for methyl group metabolism. A methionine-choline-deficient (MCD) diet leads to pathological changes in the kidney. The mechanism of the MCD diet is complex, and fundamental research is still required to provide a better understanding of the driving forces behind it. We evaluated the regional effects of the MCD diet on the metabolites of mouse kidney tissue using desorption electrospray ionization mass spectrometry imaging technology. A total of 20, 17, and 13 metabolites were significantly changed in the cortex, outer medulla, and inner medulla, respectively, of the mouse kidney tissue after the administration of the MCD diet. Among the discriminating metabolites, only three metabolites (guanidoacetic acid, serine, and nicotinamide riboside) were significantly increased, and all the other metabolites showed a significant decrease. The results showed that there were significant region-specific changes in the serine metabolism, carnitine metabolism, choline metabolism, and arginine metabolism. This study presents unique regional metabolic data, providing a more comprehensive understanding of the molecular characteristics of the MCD diet in the kidney.

Spatially resolved visualization of reprogrammed metabolism in hepatocellular carcinoma by mass spectrometry imaging

BACKGROUND

Metabolic reprogramming refers to tumor-associated metabolic alterations during tumorigenesis and has been regarded as one of the most important features of cancer. Profiling the altered metabolites and lipids in hepatocellular carcinoma with spatial signature will not only enhance our understanding of tumor metabolic reprogramming, but also offer potential metabolic liabilities that might be exploited for hepatocellular carcinoma therapy.

METHODS

We perform matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) analysis on both hepatocellular carcinoma xenograft mouse model and hepatocellular carcinoma patients. Discriminatory metabolites that altered during the development of hepatocellular carcinoma are screened and imaged in xenograft mouse model and are further validated in 21 hepatocellular carcinoma patients.

RESULTS

We discover stepwise metabolic alterations and progressively increasing metabolic heterogeneity during the growth of hepatocellular carcinoma. Arginine and its metabolites spermine and spermidine, choline and phosphatidylcholine metabolism, and fatty acids were found to be significantly reprogrammed in hepatocellular carcinoma tissues.

CONCLUSIONS

The spatially resolved profiling of the metabolites and lipids in highly heterogeneous hepatocellular carcinoma tissue will contribute to obtaining precise metabolic information for the understanding of tumor metabolic reprogramming.