No association between the CNTF null mutation and schizophrenia or personality

Astrocyte focal adhesion kinase reduces passive stress coping by inhibiting ciliary neurotrophic factor only in female mice

Astrocytes have been implicated in stress responses and produce ciliary neurotrophic factor (CNTF), which we have shown in the mouse medial amygdala (MeA) to promote passive stress coping response only in females. Pharmacological inhibition of focal adhesion kinase (FAK) upregulates CNTF expression. Here, we found that inducible knockout of FAK in astrocytes or systemic treatment with an FAK inhibitor increased passive coping behavior, i.e., immobility, in an acute forced swim stress test in female, but not male, mice. Strikingly, four weeks of chronic unpredictable stress (CUS) did not further increase passive coping in female astrocytic FAK knockout mice, whereas it exacerbated it in female wildtype mice and male mice of both genotypes. These data suggest that astrocyte FAK inhibition is required for chronic stress-induced passive coping in females. Indeed, CUS reduced phospho-FAK and increased CNTF in the female MeA. Progesterone treatment after ovariectomy activated amygdala FAK and alleviated ovariectomy-induced passive coping in wildtype, but not astrocytic FAK knockout females. This suggests that progesterone-mediated activation of FAK in astrocytes reduces female stress responses. Finally, astrocytic FAK knockout or FAK inhibitor treatment increased CNTF expression in the MeA of both sexes, although not in the hippocampus. As mentioned, MeA CNTF promotes stress responses only in females, which may explain the female-specific role of astrocytic FAK inhibition. Together, this study reveals a novel female-specific progesterone-astrocytic FAK pathway that counteracts CNTF-mediated stress responses and points to opportunities for developing treatments for stress-related disorders in women.

Ciliary neurotrophic factor is a key sex-specific regulator of depressive-like behavior in mice

Ciliary neurotrophic factor (CNTF) is produced by astrocytes and promotes neurogenesis and neuroprotection. Little is known about the role of CNTF in affective behavior. We investigated whether CNTF affects depressive- and anxiety-like behavior in adult mice as tested in the forced swim, sucrose preference and elevated-T maze tests. Female wild type CNTF+/+ mice more readily developed behavioral despair with increased immobility time and decreased latency to immobility in the forced swim test than male CNTF+/+ littermates. The lack of CNTF in CNTF-/- mice had an opposite effect on depressive-like behavior in female mice (reduced immobility time and increased sucrose preference) vs. male mice (increased immobility time). Female wildtype mice expressed more CNTF in the amygdala than male mice. Ovariectomy increased CNTF expression, as well as immobility time, which was significantly reduced in CNTF-/- mice, suggesting that CNTF mediates overiectomy-induced immobility time, possibly in the amygdala. Progesterone but not 17-β estradiol inhibited CNTF expression in cultured C6 astroglioma cells. Progesterone treatment also reduced CNTF expression in the amygdala and decreased immobility time in female CNTF+/+ but not in CNTF-/- mice. Castration did not alter CNTF expression in males nor their behavior. Lastly, there were no effects of CNTF on the elevated T-maze, a behavioral test of anxiety, suggesting that a different mechanism may underlie anxiety-like behavior. This study reveals a novel CNTF-mediated mechanism in stress-induced depressive-like behavior and points to opportunities for sex-specific treatments for depression, e.g. progesterone in females and CNTF-stimulating drugs in males.

Effect of a ciliary neurotrophic factor polymorphism on schizophrenia symptom improvement in an iloperidone clinical trial

AIMS

Presence of the null FS63TER allele of the rs1800169 polymorphism in the gene encoding the ciliary neurotrophic factor (CNTF) may increase the risk of schizophrenia. This study prospectively evaluated the CNTF rs1800169 genotype (G/G vs non-G/G) effects on response to iloperidone.

PATIENTS & METHODS

Iloperidone 24 mg/day was evaluated in a study of patients with schizophrenia. Efficacy measurements included Positive and Negative Syndrome Scale total (PANSS-T), Brief Psychiatric Rating Scale (BPRS) and Clinical, Global, Impression (CGI) scores. The step-down primary end point was the difference in PANSS-T scores based on CNTF rs1800169 G/G genotype.

RESULTS

This study genotyped 417 patients (279 iloperidone and 138 placebo) for the rs1800169 polymorphism. Iloperidone significantly improved PANSS-T, PANSS positive subscale (PANSS-P), PANSS negative subscale (PANSS-N), BPRS, Clinical Global Impression of Change (CGI-C) and Clinical Global Impression of Severity (CGI-S) scores versus placebo. G/G versus non-G/G patients had greater improvement with iloperidone versus placebo in PANSS, BPRS and CGI scores.

CONCLUSIONS

The relative treatment benefit of iloperidone compared with placebo in patients with schizophrenia is enhanced in patients homozygous G/G for the rs1800169 polymorphism.