Disrupted-in-Schizophrenia-1 is essential for normal hypothalamic-pituitary-interrenal (HPI) axis function

Area of Science:

• Neuroscience
• Genetics
• Developmental Biology

Background:

• Psychiatric disorders involve genetic and environmental factors like stress.
• Disrupted-In-Schizophrenia-1 (DISC1) is a known genetic risk factor for mental illness.
• Mechanisms linking DISC1 to stress responses are not fully understood.

Purpose of the Study:

• Investigate the role of DISC1 in the hypothalamic-pituitary-interrenal (HPI) axis, the fish homolog of the HPA axis.
• Determine if DISC1's role in stress response is evolutionarily conserved.
• Elucidate how DISC1 influences behavioral and neuroendocrine stress responses.

Main Methods:

• Utilized two lines of zebrafish homozygous mutant for disc1.
• Examined behavioral responses to stress in adult mutant zebrafish.
• Analyzed hypothalamic development and gene expression in disc1 mutant embryos.
• Assessed neuroendocrine markers (CRH, cortisol) and social behavior (shoal cohesion) in mutant larvae.

Main Results:

• DISC1 is essential for normal HPI axis function and stress responses.
• disc1 mutant zebrafish exhibit aberrant behavioral responses to stress.
• Hypothalamic development is compromised in disc1 mutant embryos, affecting key neuronal populations (rx3+, ff1b+, CRH, POMC).
• Mutant larvae show altered CRH levels, failed cortisol upregulation under stress, and abnormal social behavior.

Conclusions:

• DISC1 plays a critical, evolutionarily conserved role in regulating stress responses.
• Proper hypothalamic development, regulated by DISC1, is essential for HPA/HPI axis function.
• DISC1 dysfunction contributes to abnormal stress-related behaviors and neuroendocrine responses, relevant to psychiatric disorders.