Age affects gene expression in mouse spermatogonial stem/progenitor cells.
Spermatogenesis in man starts with spermatogonial stem cells (SSCs), and leads to the production of sperm in approximately 64 days, common to old and young men. Sperm from elderly men are functional and able to fertilize eggs and produce offspring, even though daily sperm production is more than 50% lower and damage to sperm DNA is significantly higher in older men than in those who are younger. Our hypothesis is that the SSC/spermatogonial progenitors themselves age. To test this hypothesis, we studied the gene expression profile of mouse SSC/progenitor cells at several ages using microarrays. After sequential enzyme dispersion, we purified the SSC/progenitors with immunomagnetic cell sorting using an antibody to GFRA1, a known SSC/progenitor cell marker. RNA was isolated and used for the in vitro synthesis of amplified and labeled cRNAs that were hybridized to the Affymetrix mouse genome microarrays. The experiments were repeated twice with different cell preparations, and statistically significant results are presented. Quantitative RT-PCR analysis was used to confirm the microarray results. Comparison of four age groups (6 days, 21 days, 60 days, and 8 months old) showed a number of genes that were expressed specifically in the older mice. Two of them (i.e. Icam1 and Selp) have also been shown to mark aging hematopoietic stem cells. On the other hand, the expression levels of the genes encoding the SSC markers Gfra1 and Plzf did not seem to be significantly altered by age, indicating that age affects only certain SSC/progenitor properties.
Kokkinaki
Maria
M
Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, 3900 Reservoir Road NW, Washington, District of Columbia 20057, USA.
Lee
Tin-Lap
TL
He
Zuping
Z
Jiang
Jiji
J
Golestaneh
Nady
N
Hofmann
Marie-Claude
MC
Chan
Wai-Yee
WY
Dym
Martin
M
D000375:Aging / Q000235:genetics*; D000818:Animals; D002452:Cell Count; D016922:Cellular Senescence / Q000235:genetics; D015870:Gene Expression / Q000235:genetics*; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors / Q000032:analysis / Q000235:genetics; D006412:Hematopoietic Stem Cells / Q000737:chemistry / Q000378:metabolism; D018189:Immunomagnetic Separation; D018799:Intercellular Adhesion Molecule-1 / Q000235:genetics; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D020411:Oligonucleotide Array Sequence Analysis; D012313:RNA / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051149:Selenoprotein P / Q000235:genetics; D013093:Spermatogonia / Q000737:chemistry / Q000166:cytology / Q000378:metabolism*; D013234:Stem Cells / Q000737:chemistry / Q000166:cytology / Q000378:metabolism*; D013737:Testis / Q000166:cytology
C494988:Gfra1 protein, mouse; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; C090509:Icam1 protein, mouse; D051149:Selenoprotein P; D018799:Intercellular Adhesion Molecule-1; D012313:RNA