CELLULAR SIGNALING MECHANISMS INVOLVED IN THE 3-DIMENSIONAL ASSEMBLY AND DIFFERENTIATION OF PC12 PHEOCHROMOCYTOMA CELLS UNDER SIMULATED MICROGRAVITY IN NASA ROTATING WALL VESSEL BIOREACTORS

Peter I. Lelkes, Brian R. Unsworth

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

Rotating Wall Vessel (RWV) Bioreactors simulate microgravity and facilitate 3-D tissue-like assembly through spatial co-localization and cell-cell interactions. This unique cell culture venue is well suited to assess the role of microenvironmental cues in the assembly and tissue-specific differentiation of cells in culture. Our long term goal is to use RWV Bioreactors for generating functional neuroendocrine 3-D constructs which may be useful as clinical replacement tissue in treating neurodegenerative diseases. As a model we are using PC 12 pheochromocytoma cells, a bipotential rat adrenal medullary tumor cell line. PC 12 cells differentiate, depending on exogenous factors, either along the neuronal or the neuroendocrine pathway. PC 12 cells, when maintained for up to 20 days in RWV Bioreactors, form macroscopic tissue-like aggregates which exhibit enhanced expression of neuroendocrine, adrenergic differentiation markers (Lelkes et al., In Vitro Devel. Biol, 1998, 34: 316 -325). We hypothesized that exposure of PC 12 cells to the “simulated microgravity” culture conditions in the RWV Bioreactors, might selectively activate signal transduction pathways leading to enhanced neuroendocrine adrenergic differentiation. Using quantitative RT-PCR we demonstrated rapid upregulation of an adrenergic marker, phenylethanolamine-N-methyl transferase (PNMT), in short term RWV cultures. Concomitantly, we found, by electrophoretic mobility shift assays, differential induction of nuclear transcription factors, such as GRE and SP-1, which are known to be involved in the glucocorticoid-induced activation of PNMT. Conversely, upon short term culture of PC 12 cells in RWV, the neuronal traits of the cells were impaired. Upon exposure to simulated microgravity, MAPK. signaling (erk and jnk) was constitutively activated, while nerve-growth factor (NGF)-induced activation of erk, was abrogated. These results suggest that the culture conditions in the RWV Bioreactors are sufficient to induce PC 12 cell differentiation towards the neuroendocrine, phenotype by upregulating “adrenergic” gene expression, while downregulating neurotrophin signaling pathways.

Original languageEnglish
Title of host publicationAdvances in Heat and Mass Transfer in Biotechnology
PublisherAmerican Society of Mechanical Engineers (ASME)
Pages35-41
Number of pages7
ISBN (Electronic)9780791815984
DOIs
StatePublished - 1998
Externally publishedYes
EventASME 1998 International Mechanical Engineering Congress and Exposition, IMECE 1998 - Anaheim, United States
Duration: Nov 15 1998Nov 20 1998

Publication series

NameASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE)
Volume1998-E

Conference

ConferenceASME 1998 International Mechanical Engineering Congress and Exposition, IMECE 1998
Country/TerritoryUnited States
CityAnaheim
Period11/15/9811/20/98

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