Details

Autor(en) / Beteiligte

• Bouhy, Delphine
• Ghasemlou, Nader
• Lively, Starlee
• Redensek, Adriana
• Rathore, Khizr I
• Schlichter, Lyanne C
• David, Samuel

Titel

Inhibition of the Ca²⁺-dependent K⁺ channel, KCNN4/KCa3.1, improves tissue protection and locomotor recovery after spinal cord injury

Ist Teil von

• The Journal of neuroscience, 2011-11, Vol.31 (45), p.16298-16308

Ort / Verlag

United States: Society for Neuroscience

Erscheinungsjahr

2011

Quelle

MEDLINE

Beschreibungen/Notizen

• Spinal cord injury (SCI) triggers inflammatory responses that involve neutrophils, macrophages/microglia and astrocytes and molecules that potentially cause secondary tissue damage and functional impairment. Here, we assessed the contribution of the calcium-dependent K⁺ channel KCNN4 (KCa3.1, IK1, SK4) to secondary damage after moderate contusion lesions in the lower thoracic spinal cord of adult mice. Changes in KCNN4 mRNA levels (RT-PCR), KCa3.1 protein expression (Western blots), and cellular expression (immunofluorescence) in the mouse spinal cord were monitored between 1 and 28 d after SCI. KCNN4 mRNA and KCa3.1 protein rapidly increased after SCI; double labeling identified astrocytes as the main cellular source accounting for this upregulation. Locomotor function after SCI, evaluated for 28 d in an open-field test using the Basso Mouse Scale, was improved in a dose-dependent manner by treating mice with a selective inhibitor of KCa3.1 channels, TRAM-34 (triarylmethane-34). Improved locomotor function was accompanied by reduced tissue loss at 28 d and increased neuron and axon sparing. The rescue of tissue by TRAM-34 treatment was preceded by reduced expression of the proinflammatory mediators, tumor necrosis factor-α and interleukin-1β in spinal cord tissue at 12 h after injury, and reduced expression of inducible nitric oxide synthase at 7 d after SCI. In astrocytes in vitro, TRAM-34 inhibited Ca²⁺ signaling in response to metabotropic purinergic receptor stimulation. These results suggest that blocking the KCa3.1 channel could be a potential therapeutic approach for treating secondary damage after spinal cord injury.