Essentially, all human tissues and organs have the ability to heal themselves and to renew damaged or dying cells, in which case the human brain acts fundamentally differently. The vast majority of nerve cells are produced before birth, and the regenerative capacity of the human brain is limited to a few regions. So the average age of neurons in the adult brain is much higher than that of any other cell type in the body, but how do human neurons protect themselves from accidental cell death and maintain high levels of function throughout their lives?
Recently, a study published in the international journal "Diverse maturity-dependent and complementary anti-apoptotic brakes safeguard human iPSC-derived neurons from cell death" in Cell Death & Disease, Scientists from Germany have investigated the cellular adaptability of human neurons to ensure their resilience; They use human induced pluripotent stem cells (iPSCs) to produce human neurons in culture dishes, Over time these neuronal cells mature, And to produce models of brain development, This allows the researchers to directly compare young, newborn neurons and old, more mature, neuronal cells.
Professor Philipp Koch explained that if cells are under pressure or damaged, under normal circumstances will try to adapt to these conditions, for example, by activating the reactive repair program, under a certain degree of damage, a cell death program called apoptosis (apoptosis) can be activated to eliminate damaged cells or tissues, the researchers point out that this programmed cell death can be strictly controlled by various molecular pathways, and into cell death threshold is very high in human neurons.
In fact, once human neurons mature, they are endowed with complex and redundant preemptive strategies to protect against stress and cell death; major components of cell death machines such as Caspases are downregulated or completely closed, while protective pathways such as anti-apoptotic Bcl-2 family proteins of apoptotic proteins (IAPs) inhibitors are upregulated. It seems that the brain will develop a very refined, complex, and complementary network to protect cells from death, perhaps as an evolutionary adaptation to its reduced ability to regenerate. These protective mechanisms of mature neurons may also partially explain why most neurodegenerative diseases are often protected for decades and may only occur at older ages; neurodegenerative diseases may result from a combination of accumulated cellular stress and damage and the weakening of maturity-dependent protective mechanisms.
Taken together, the present results highlight how human neurons are endowed with complex and redundant preemptive strategies to protect cells against stress and cell death.
