Programmed Celular Death: A key process in physiology and pathology.
The concept of death as an accidental and painful event, even when occurring at the cellular level, is changing. Developmental Biology studies in several model organisms have shown that cell death is a naturally occurring process during normal development of multicellular organisms, from worms to humans. Genetic analysis, originally performed in Caenorhabditis elegans, has revealed that cell death is a highly regulated process: cells express the molecular components of the pathway to commit suicide, depending of the balance of signals coming from their cellular environment. The elucidation of this pathway is changing the viewpoint on many diseases. Cancer, for instance, in often due to lack of cell death, while cell death in excess may trigger tissue degeneration. In this article we also present an overview of the mechanisms of programmed cell death, the most relevant biological aspect, based mainly on studies in the developing nervous system.