
ジフルオロメチルオルニチン(DFMO)は、スナイダー-ロビンソン症候群患者由来の細胞において、スペルミジンの蓄積を減少させ、スペルミンの生成を促進することで、異常なスペルミジン/スペルミン比を是正する。


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Snyder-Robinson Syndrome (SRS) is caused by mutations in the spermine synthase ( SMS ) gene, the enzyme product of which converts the polyamine spermidine into spermine. Affecting primarily males, common manifestations of SRS include intellectual disability, osteoporosis, hypotonic musculature, and seizures, along with other, more variable symptoms. Currently, medical management focuses on treating symptoms without addressing the underlying molecular cause of the disease.

Reduced SMS catalytic activity in cells of SRS patients causes the accumulation of spermidine, while spermine levels are reduced. The resulting exaggeration in spermidine-to-spermine ratio is a biochemical hallmark of SRS that tends to correlate with symptom severity in the patient. Our studies aim to pharmacologically manipulate polyamine metabolism to correct this polyamine imbalance and investigate the potential of this approach as a therapeutic strategy for affected individuals.

Here we report the use of 2-difluoromethylornithine (DFMO; eflornithine), an FDA-approved inhibitor of polyamine biosynthesis, in re-establishing normal spermidine-to-spermine ratios in SRS patient cells. Through mechanistic studies, we demonstrate that, while reducing spermidine biosynthesis, DFMO also stimulates the conversion of existing spermidine into spermine in cell lines with hypomorphic variants of SMS . Further, DFMO treatment induces a compensatory uptake of exogenous polyamines, including spermine and spermine mimetics, cooperatively reducing spermidine and increasing spermine levels. In a Drosophila SRS model characterized by reduced lifespan, adding DFMO to the feed extends lifespan. As nearly all known SRS patient mutations are hypomorphic, these studies form a foundation for future translational studies with significant therapeutic potential.

### Competing Interest Statement

The Casero and Stewart Laboratory receive funding from Panbela Therapeutics, Inc. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.

Difluoromethylornithine rebalances aberrant polyamine ratios in Snyder-Robinson syndrome: mechanism of action and therapeutic potential

スナイダー-ロビンソン症候群における異常なポリアミン比を是正するジフルオロメチルオルニチン-作用機序と治療の可能性


スナイダー-ロビンソン症候群における異常なポリアミン比を是正するジフルオロメチルオルニチン: 作用機序と治療の可能性
