Effects of interferon-gamma and tumor necrosis factor-alpha on survival and differentiation of oligodendrocyte progenitors.
OBJECTIVE
There is strong evidence from recent clinical studies that ascending intrauterine infection is associated with an increased incidence of periventricular leukomalacia in very premature fetuses. Periventricular leukomalacia is characterized by disrupted myelination from a loss of oligodendrocyte progenitors. We investigated the effects of proinflammatory cytokines on the survival and differentiation of this cell type.


METHODS
Cultures of more than 90% A2B5-positive progenitors were prepared from neonatal rats and kept for 3 days in medium supplemented with factors that stimulate cell proliferation. After 1 day in proliferation medium, cells were treated with interferon-gamma (100 U/mL) and tumor necrosis factor-alpha (100 ng/mL) for 48 hours triggering an increase in apoptotic A2B5 progenitor cells from 3.2 +/- 2.3% to 11.0 +/- 2.6%. After cytokine treatment cultures were transferred to medium containing factors to promote differentiation of progenitors into the myelinating phenotype.


RESULTS
In cytokine pretreated cultures, only 2.6 +/- 1.1% of total cells survived after a total of 9 days in vitro, whereas in untreated cultures most cells differentiated as shown by expression of myelin basic protein, myelin-associated glycoprotein, 2,3-cyclic nucleotide 3-phosphodiesterase, and myelin oligodendrocyte-specific protein. Using ten-fold reduced concentrations of combined interferon-gamma (10 U/mL) and tumor necrosis factor-alpha (10 ng/mL) pretreatment resulted in a survival to 11.2 +/- 4.9% of total cells with 36.3 +/- 11.6% A2B5-positive cells at day 9. This indicates a major enrichment of undifferentiated cells compared with untreated controls which harbored only 1.0 +/- 0.3% A2B5-positive cells.


CONCLUSIONS
Inflammatory cytokines not only induced apoptotic cell death but also prevented the differentiation of immature A2B5 oligodendrocyte progenitors into the myelinating phenotype.
Departments ofDepartment of Obstetrics and Gynecology, University of Bochum, Bochum, Germany.
Beatrix
B
Feldhaus
Irmgard D
ID
Dietzel
Rolf
R
Heumann
Richard
R
Berger
D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects*; D002478:Cells, Cultured; D006801:Humans; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D007231:Infant, Newborn; D007371:Interferon-gamma / Q000494:pharmacology*; D007969:Leukomalacia, Periventricular; D009186:Myelin Sheath / Q000502:physiology; D009836:Oligodendroglia / Q000166:cytology / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013234:Stem Cells / Q000166:cytology / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma