PT  - JOURNAL ARTICLE
AU  - Sharon Averill
AU  - Danny R. Davis
AU  - Peter J. Shortland
AU  - John V. Priestley
AU  - Stephen P. Hunt
TI  - Dynamic Pattern of Reg-2 Expression in Rat Sensory Neurons after Peripheral Nerve Injury
AID  - 10.1523/JNEUROSCI.22-17-07493.2002
DP  - 2002 Sep 01
TA  - The Journal of Neuroscience
PG  - 7493--7501
VI  - 22
IP  - 17
4099  - http://www.jneurosci.org/content/22/17/7493.short
4100  - http://www.jneurosci.org/content/22/17/7493.full
SO  - J. Neurosci.2002 Sep 01; 22
AB  - The 16 kDa pancreatitis-associated protein Reg-2 has recently been shown to facilitate the regeneration of motor and sensory neurons after peripheral nerve injury in the adult rat. Reg-2 has also been shown to be a neurotrophic factor that is an essential intermediate in the pathways through which CNTF supports the survival of motor neurons during development. Here we report the dynamic expression of Reg-2 in rat sensory neurons after peripheral nerve injury. Reg-2 is normally not expressed by dorsal root ganglion (DRG) cells, but we show, using immunocytochemistry, that Reg-2 is rapidly upregulated in DRG cells after sciatic nerve transection and after 24 hr recovery is expressed almost exclusively in small-diameter neurons that bind the lectin Griffonia simplicifolia IB4 and express the purinoceptor P2X3. However, by 7 d after axotomy, Reg-2 is expressed in medium to large neurons and coexists partly with the neuropeptides galanin and neuropeptide Y, which are also upregulated after peripheral nerve transection. At this time point, Reg-2 is no longer expressed in small neurons, and there is no colocalization with IB4 binding neurons, demonstrating a shift in Reg-2 expression from one subset of DRG neurons to another. We also show by double labeling for activating transcription factor 3, a transcription factor that is upregulated after nerve injury, that Reg-2 expression occurs predominantly in axotomized DRG cells but that a small percentage of uninjured DRG cells also upregulate Reg-2. The selective expression within IB4/P2X3 cells, and the dynamic shift from small to large cells, is unique among DRG peptides and suggests that Reg-2 has a distinctive role in the injury response.