Transdetermination: Function, Tasks, Role & Diseases

A transdetermination in biology represents the reprogramming of a differentiated somatic cell. In general, the process of differentiation of somatic cells from the fertilized egg to the fully formed organism is irreversible. However, under certain conditions, a cell determined in its differentiation can be reprogrammed.

What is transdetermination?

In general, the process of differentiation of somatic cells from the fertilized egg to the fully formed organism proceeds irreversibly. Transdetermination means the transformation from one determinate state to another determinate state. In biology, transdetermination is characterized by the reprogramming of an already differentiated body cell into another differentiated body cell. In the case of humans and most multicellular animals, the development of organisms begins with the fertilized egg cell. The entire organism develops from this first cell. As the cells divide, increasing differentiation or specialization of the individual cells occurs during embryogenesis. This is how the organs develop. Liver cells, for example, have the same genetic information as heart cells. In both cell types, however, the genetic information required in each case is called up by different genes. During differentiation, certain genes are silenced by methylations or modifications of histones. Differentiation occurs by silencing different genes from cell line to cell line. Thus, in transdetermination, inactive genes are reactivated and previously activated genes become inactive again. An example would be the complex transformation of a skin cell into a liver cell.

Function and task

The fertilized egg cell is the first cell of the organism. It is the original stem cell of all later highly differentiated cells. In this context, together with the first eight cells, it is called the totipotent stem cell. These first cells are still completely undifferentiated and can each develop into an independent organism. After the eighth cell division, pluripotent or embryonic stem cells are formed. These can still transform into the cells of all three germ layers (ectoderm, mesoderm, endoderm). However, they have already lost the ability to develop into independent organisms. Further development leads to the postembryonic stem cells, which are divided into fetal, neonatal, and adult stem cells depending on the stage of development. The postembryonic stem cells already represent different cell lineages that can transform into specific organ systems. They also still possess differentiation potential, which, however, is only related to specific cell types. They are referred to as multipotent stem cells. For example, neural stem cells can still transform into different forms of nerve cells, but no longer into blood cells. Transdifferentiation or transdetermination of the cells is possible. However, it is controversial whether a fully differentiated body cell can be reprogrammed. To do so, the expression of thousands of genes would have to be simultaneously activated and thousands of other genes simultaneously deactivated in order to transform a skin cell into a muscle cell, for example. Until now, it has been assumed that only adult stem cells are still capable of this. Their differentiation potential even transcends the cotyledon. The reprogramming usually occurs in two steps. First, dedifferentiation of the cell occurs. Then, after cell divisions, differentiation into another orientation occurs again. Within the organism, such transdetermination takes place, for example, in wound healing. Adult stem cells develop into a wide variety of cell types that are needed for the healing process. For medicine, this will presumably open up excellent prospects in the future as an alternative to today’s transplantation technology. Diseased organs could be grown directly from the patient’s own adult stem cells. Years of drug treatment to limit rejection reactions would become a thing of the past. In various in vitro studies of cell cultures, dedifferentiation and redifferentiation of cells could be achieved with the help of a growth factor.In the context of stem cell research, it was discovered that stem cells may be able to replace cells destroyed in myocardial infarction. However, the results also suggest that healing is not based on replacement by the trans-differentiated cells, but on stimulation to cell growth and differentiation processes. Adult stem cells also prove effective in regenerating cartilage and bone.

Diseases and ailments

In connection with transdetermination, serious diseases occur repeatedly. The development of cancer is based on the dedifferentiation of body cells. Changes within the cell can result in undifferentiated cell division, which can spread throughout the body by forming metastases. Causes may include somatic mutations, viruses, or out-of-control cell profiling during healing processes. Dedifferentiation can occur rapidly. However, there are also forms of cancer in which the tumor remains differentiated for quite a long time. However, no new differentiation then occurs after the phase of dedifferentiation. The dividing cells are degenerated and move further away from the initial state after each cell division. Genetic information is also subject to constant change. For example, wound healing is a natural process based on transdetermination. Here, adult stem cells transform into differentiated skin cells, connective tissue cells or cells of other types. In rare cases, however, a malignant tumor may form as a result of the constant cell divisions. A similar situation can also occur after immune reactions. Among other things, lymphomas are an expression of an immune system that is out of control.