Micro-control of liver metabolism

Researchers at TIFR have discovered molecular anticipation of feeding in the liver that is essential to ensure that the body, after fasting, adapts to use incoming nutrients upon re-feeding. Their findings, published in the international journal Cell Reports, show that very small RNA molecules called microRNAs control major metabolic pathways by inhibiting synthesis of proteins, and thus contribute to maintenance of blood glucose levels.

The liver is one of the central metabolic organs that plays a pivotal role in maintaining organismal health and lifespan. All living organisms go through feed-fast cycles in which the body breaks down fats during fasting to meet energy demands and uses glucose or carbohydrates following food consumption. Inflexibility to oscillate between these processes comes from the failure of organs (or organisms) to switch metabolic pathways.

Both over- or under-utilization of either fat or glucose is known to affect health of all life forms. In highly evolved species, the liver acts as the primary organ to regulate both fat and glucose metabolism and ensure that there is neither over- nor under-utilization of these energy sources. Liver dysfunctions are known to be associated with obesity and diabetes. Abnormal liver metabolism is one of the primary drivers of fatty liver disease, which is highly prevalent, more so among Indians. Thus, molecular mechanisms within liver cells that bring about a global change in gene expression from a fasted to a re-fed state become critical. There has been a recent surge in the efforts by scientists all over the world to discover molecular factors that respond to food intake (including time of the day feeding) and circadian rhythm (light-dark cycles), specifically in the liver, and that affect whole body metabolism.

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