Copper-iron metabolism interaction in rats

The prominent alteration in transcriptome and metabolome of Mycobacterium bovis BCG str. Tokyo 172 induced by vitamin B1

BACKGROUND

Vitamin B1 (VB1) is a crucial dietary nutrient and essential cofactor for several key enzymes in the regulation of cellular and metabolic processes, and more importantly in the activation of immune system. To date, the precise role of VB1 in Mycobacterium tuberculosis remains to be fully understood.

RESULTS

In this study, the transcriptional and metabolic profiles of VB1-treated Mycobacterium. bovis BCG were analyzed by RNA-sequencing and LC-MS (Liquid chromatography coupled to mass spectrometry). The selection of BCG strain was based on its common physiological features shared with M. tuberculosis. The results of cell growth assays demonstrated that VB1 inhibited the BCG growth rate in vitro. Transcriptomic analysis revealed that the expression levels of genes related to fatty acid metabolism, cholesterol metabolism, glycolipid catabolism, DNA replication, protein translation, cell division and cell wall formation were significantly downregulated in M. bovis BCG treated with VB1. In addition, the metabolomics LC-MS data indicated that most of the amino acids and adenosine diphosphate (ADP) were decreased in M. bovis BCG strain after VB1 treatment.

CONCLUSIONS

This study provides the molecular and metabolic bases to understand the impacts of VB1 on M.bovis BCG.

The impact of iron content in a diet high in fat, fructose, and salt on metabolic state and mineral status of rats

The purpose of the study was to assess the influence of dietary iron content on lipid and carbohydrate metabolism and on zinc and copper status in rats fed with a diet high in fat, fructose, and salt. Wistar rats were fed with diets high in fat, fructose, and salt, containing differing amounts of iron, namely, deficit, normal, and high levels. After 6 weeks, the animals were weighed and killed. The liver, heart, and pancreas were collected, as were blood samples. The total cholesterol, triglycerides, fasting glucose, and insulin levels in the serum were measured. The iron, zinc, and copper concentrations in tissues and serum were determined. It was found that in rats fed with the iron-deficit diet, cholesterol and glucose profiles improved. Both deficit and excess iron in the diet decreased insulin concentration in rats and disturbed iron, zinc, and copper status. High-iron level in the diet decreased the relative mass of the pancreas. In conclusion, the decrease in serum insulin concentration observed in rats fed with the modified diet high in iron was associated with iron and copper status disorders, and also, with a relatively diminished pancreas mass. A deficit of iron in the diet improved lipid and carbohydrate metabolism in rats.

The multi-layered regulation of copper translocating P-type ATPases

The copper-translocating Menkes (ATP7A, MNK protein) and Wilson (ATP7B, WND protein) P-type ATPases are pivotal for copper (Cu) homeostasis, functioning in the biosynthetic incorporation of Cu into copper-dependent enzymes of the secretory pathway, Cu detoxification via Cu efflux, and specialized roles such as systemic Cu absorption (MNK) and Cu excretion (WND). Essential to these functions is their Cu and hormone-responsive distribution between the trans-Golgi network (TGN) and exocytic vesicles located at or proximal to the apical (WND) or basolateral (MNK) cell surface. Intriguingly, MNK and WND Cu-ATPases expressed in the same tissues perform distinct yet complementary roles. While intramolecular differences may specify their distinct roles, cellular signaling components are predicted to be critical for both differences and synergy between these enzymes. This review focuses on these mechanisms, including the cell signaling pathways that influence trafficking and bi-functionality of Cu-ATPases. Phosphorylation events are hypothesized to play a central role in Cu homeostasis, promoting multi-layered regulation and cross-talk between cuproenzymes and Cu-independent mechanisms.