Although we did not observe functional differences in tight junction function in C9 mice (through assessing 14C-sucrose transport across the BBB), we were still interested to assess the abundance of major tight junction and gap junction proteins [44] in BMECs that were isolated from the C9 and WT mice, as altered expression of tight junction proteins in the spinal cords (though not in the brain) have been reported in individuals with ALS and in the SOD1G93A mouse model [45,46]. Here, C9 is linked to amyotrophic lateral sclerosis.