The astrocyte marker Aldh1L1 does not reliably label enteric glial cells.

Enteric glial cells are increasingly acknowledged as important partners of enteric neurons in the control of gastrointestinal function. They share morphological features and expression of antigenic markers with astrocytes of the central nervous system. Recently, aldehyde dehydrogenase 1 family member L1 (Aldh1L1) has been proposed as a novel and specific marker for astrocytes. Taking the known similarities between astrocytes and enteric glia into account, we sought to investigate whether enteric glial cells also express Aldh1L1. To this end, we performed immunostaining on preparations of myenteric plexus obtained from adult Aldh1L1-eGFP bacterial artificial chromosome (BAC) transgenic mice and found that the Aldh1L1 promoter is indeed active in enteric glia, albeit mainly in cells residing outside the myenteric ganglia. Apart from enteric glia, we also observed eGFP expression in interstitial cells of Cajal. Furthermore, myenteric ganglia of the large intestine contained eGFP positive neurons. Taken together, our data indicate that Aldh1L1 is not a suitable marker for enteric glial cells.