Absence of evidence that Slc12a8 encodes a nicotinamide mononucleotide transporter

Schmidt MS, Brenner C · Nature Metabolism

A formal rebuttal arguing that the reported Slc12a8 data do not establish a dedicated NMN transporter, and that the prevailing model — NMN dephosphorylated to nicotinamide riboside before cell entry — remains unrefuted.

Limitations

A correspondence item presenting argument and reanalysis rather than new experiments. Its senior author declares that he owns stock in and is chief scientific adviser to ChromaDex, which sells the rival precursor nicotinamide riboside.