TY - JOUR
T1 - Upregulation of Vesicular Glutamate Transporter 2 and STAT3 Activation in the Spinal Cord of Mice Receiving 3,3′-Iminodipropionitrile
AU - Ohgomori, Tomohiro
AU - Yamasaki, Ryo
AU - Kira, Jun ichi
AU - Jinno, Shozo
N1 - Funding Information:
Grant Information This work was supported in part by JSPS KAKENHI Grant Numbers 25860234 (to T.O.), 17K00858 (to T.O.), 15H04267 (to S.J.), and Grants-in-Aid for Scientific Research on the Innovative Areas of “Deciphering sugar chain-based signals regulating integrative neuronal functions” (26110714 to S.J.).
Funding Information:
The authors thank Ms. Machiko Endoh for her technical and secretarial assistance. We also thank Editage (www.editage.jp) for English language editing. We also appreciate the technical assistance from The Research Support Center, Research Center for Human Disease Modeling, Kyushu University Graduate School of Medical Sciences. The Committee of Ethics on Animal Experiment in Kyushu University (No. A28-218-0) approved the procedure. The authors declare that they have no conflicts of interest.
PY - 2018/5/1
Y1 - 2018/5/1
N2 - Chronic administration of 3,3′-iminodipropionitrile (IDPN) causes axonal impairment. Although controversy still remains, it has been suggested that IDPN intoxication mimics the axonopathy of amyotrophic lateral sclerosis (ALS). Interestingly, recent studies including our own showed that signal transducer and activator of transcription 3 (STAT3) in spinal α-motoneurons was activated in both IDPN-treated mice and SOD1G93A mice, a genetic model of familial ALS. Because activation of STAT3 occurs in response to various stimuli, such as axonal injury, ischemia, and excessive glutamate, here we focused on a potential link between phosphorylated STAT3 (pSTAT3, an active form) and vesicular glutamate transporter 2 (VGluT2, a regulator of glutamate storage and release) in IDPN-treated mice and SOD1G93A mice. Impairment of axonal transport was confirmed by western blot analysis: the expression levels of phosphorylated neurofilament H were elevated in both models. As shown in SOD1G93A mice, the expression frequencies of VGluT2 in synaptophysin-positive (SYP)+ presynaptic terminals around spinal α-motoneurons were significantly higher in IDPN-treated mice than in vehicle controls. The coverages of spinal α-motoneurons by VGluT2+ presynaptic terminals were more elevated around pSTAT3+ cells than around pSTAT3− cells in IDPN-treated mice and SOD1G93A mice. Considering that excessive glutamate is shown to be involved in axonal impairment and STAT3 activation, the present results suggest that IDPN-induced upregulation of VGluT2 may result in an increase in glutamate, which might cause axonopathy and induction of pSTAT3. The link between upregulation of VGluT2 and activation of STAT3 via glutamate may represent a common pathological feature of IDPN-treated mice and SOD1G93A mice.
AB - Chronic administration of 3,3′-iminodipropionitrile (IDPN) causes axonal impairment. Although controversy still remains, it has been suggested that IDPN intoxication mimics the axonopathy of amyotrophic lateral sclerosis (ALS). Interestingly, recent studies including our own showed that signal transducer and activator of transcription 3 (STAT3) in spinal α-motoneurons was activated in both IDPN-treated mice and SOD1G93A mice, a genetic model of familial ALS. Because activation of STAT3 occurs in response to various stimuli, such as axonal injury, ischemia, and excessive glutamate, here we focused on a potential link between phosphorylated STAT3 (pSTAT3, an active form) and vesicular glutamate transporter 2 (VGluT2, a regulator of glutamate storage and release) in IDPN-treated mice and SOD1G93A mice. Impairment of axonal transport was confirmed by western blot analysis: the expression levels of phosphorylated neurofilament H were elevated in both models. As shown in SOD1G93A mice, the expression frequencies of VGluT2 in synaptophysin-positive (SYP)+ presynaptic terminals around spinal α-motoneurons were significantly higher in IDPN-treated mice than in vehicle controls. The coverages of spinal α-motoneurons by VGluT2+ presynaptic terminals were more elevated around pSTAT3+ cells than around pSTAT3− cells in IDPN-treated mice and SOD1G93A mice. Considering that excessive glutamate is shown to be involved in axonal impairment and STAT3 activation, the present results suggest that IDPN-induced upregulation of VGluT2 may result in an increase in glutamate, which might cause axonopathy and induction of pSTAT3. The link between upregulation of VGluT2 and activation of STAT3 via glutamate may represent a common pathological feature of IDPN-treated mice and SOD1G93A mice.
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U2 - 10.1007/s12640-017-9822-x
DO - 10.1007/s12640-017-9822-x
M3 - Article
C2 - 28965218
AN - SCOPUS:85030158416
VL - 33
SP - 768
EP - 780
JO - Neurotoxicity Research
JF - Neurotoxicity Research
SN - 1029-8428
IS - 4
ER -