mTOR: A KEY GENE IN UNDERSTANDING THE GREATER PSYCHO-PHSYCIAL VULNERABILITY IN PEOPLE WITH INTELLECTUAL AND RELATIONAL DEVLEOPMENTAL DISORDERS - FIRST PART

In 2009, it was discovered that a substance of bacterial origin can significantly lengthen the duration of life of some mammals. This substance, named rapamycin from the indigenous name of the island (Rapa Nui) in which it was initially found, limits the activity of a gene called TOR, mTOR in mammals. An increasing number of research  is indicating that TOR has a key role in some of the principle regulatory mechanisms of cell physiology and systems with which they communicate: nervous, endocrine, and immune. TOR exerts its action by encoding for an enzyme that in the cytoplasm of cells combine itself with several other proteins forming a complex called TORC.

One of the main roles of TOR is a sensor of nutrients and is done with the support of insulin. When food is plentiful more insulin is produced and the activity of TORCincreases. This results in qualitative and quantitative consistent cell growth. The activity of TORC also produces a reduction of intracellular autophagic processes, aimed to eliminate damaged mitochondria and other intracellular waste. When nutrients are scarce, TORC is inhibited along with the growth and cell replication. Instead, this intensifies autophagy, in order to recycle nutrients and materials for cell maintenance.  

The stimulation of mTOR makes cells less sensitive to signals of insulin. Stable excessive food intake, therefore, makes the cells more insulin-resistant with the risk of developing diabetes.

The activity of mTOR is inhibited even by low availability of oxygen, DNA damage, or other forms of endocellular stress.  

The surge in growth regulated by mTOR is essential for individual development and reproduction but , once the maturity is reached, it also becomes the engine of aging. It contribute to the growth of smooth muscle of arteries and atherosclerotic plaques, to the accumulation of body fat, to the reduction of the glucose tolerance, to the multiplication of harmful cells such as osteoclasts that break down bone or tumor cells, and to the aggregation in neurons of proteins resistant toneurodegenerative processes such as the amyloid of Alzheimer’s or other.

In animal models of Rett syndrome and Down syndrome, including a relational or intellectual developmental disorder, mTOR appears to show an early hyperactivity. 

This article has been translated and adapted to English (American) by Courtney Diamond