| dc.description | The signal transducer and activator of transcription 5 (STAT5) is a transcription factor recruited by numerous cytokines.
STAT5 is important for several physiological functions, including body and tissue growth, mammary gland development,
immune system and lipid metabolism. However, the role of STAT5 signaling for brain functions is still poorly investigated,
especially regarding cognitive aspects. Therefore, the objective of the present study was to investigate whether brain STAT5
signaling modulates learning and memory formation. For this purpose, brain-specific STAT5 knockout (STAT5 KO) mice
were studied in well-established memory tests. Initially, we confirmed a robust reduction in STAT5a and STAT5b mRNA
levels in different brain structures of STAT5 KO mice. STAT5 KO mice showed no significant alterations in metabolism,
growth, somatotropic axis and spontaneous locomotor activity. In contrast, brain-specific STAT5 ablation impaired learning
and memory formation in the novel object recognition, Barnes maze and contextual fear conditioning tests. To unravel
possible mechanisms that might underlie the memory deficits of STAT5 KO mice, we assessed neurogenesis in the hippocampus,
but no significant differences were observed between groups. On the other hand, reduced insulin-like growth
factor-1 (IGF-1) mRNA expression was found in the hippocampus and hypothalamus of STAT5 KO mice. These findings
collectively indicate that brain STAT5 signaling is required to attain normal learning and memory. Therefore, STAT5 is an
important downstream cellular mechanism shared by several cytokines to regulate cognitive functions. | |
