Objective: Stem cells are found in various tissues and under certain physiological or experimental conditions, they can be induced to differentiate into other cell types. Based on their origin, they can be divided into two groups, embryonic and adultstem cells. The major setbacks regarding embryonic stem cells are ethical concerns and their immunological incompatibility. Thus, there are extensive efforts to facilitate stem cell production by reprogramming the somatic or differentiated cells, which can be used both for research and therapeutic applications. Therefore, access to a suitable cell source, along with cost effective and safer methods for dedifferentiation and reprogramming are appealing to many researchers.keratinocytes exhibit high tendency to be reprogrammed in the presence of various inducers. Thus,in the current study, HaCaT keratinocytes were used as a model for cell reprogramming by co-culturing with a pluripotent tissue. Methods: In order to have access to the pluripotent tissue, white New Zealand rabbit's pinnaswere punched and after 48 hours, regenerating rings were obtained by a second punch around the first ones. HaCaT cells were co-cultured with these rings for 48 hours. Then total RNA ofHaCaT cells was extracted and changes in expression of some genes related topluripotency were assessed by real time- PCR. Results: The results showed that, expression of OCT4,NANOG,cMYC and KRT19 (a keratinocyte stemness marker) were induced in HaCaT cells after co-culturing with regenerating tissues originated from the pinnas. Conclusion: In conclusion, this regenerating tissue may secrete some small molecules which can induce dedifferentiation and pluripotentcy in HaCaT human keratinocytes. Finding these molecules and the mechanisms of their action can introduce new methods for cellular reprogramming which may also be useful in regenerative medicine.

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