CysLT1R downregulation reverses intracerebroventricular streptozotocin-induced memory impairment via modulation of neuroinflammation in mice

- STZ (ICV) microinjection induces memory deficit in mice through hippocampal CysLT1R upregulation.
- shRNA-mediated knockdown of CysLT1R reverses STZ-induced memory impairment.
- Pranlukast, a CysLT1R antagonist, reverses STZ-induced neuroinflammation by blocking NF-κB signaling.

Our previous studies showed that cysteinyl leukotrienes receptor 1 (CysLT1R) is upregulated in amyloid-β (Aβ)-induced neurotoxicity and that administration of CysLT1R antagonists such as pranlukast or montelukast can ameliorate memory impairment in mice. In the current study, we sought to explore the role of CysLT1R in intracerebroventricular streptozotocin (STZ-ICV)-induced mouse model of memory impairment and neuroinflammation through shRNA-mediated knockdown of CysLT1R and also its pharmacological blockade by pranlukast. ICR mice were infused with STZ (3.0 mg/kg) by a single bilateral stereotaxic ICV microinjection followed by administration of CysLT1R-shRNA (intra-hippocampal) or pranlukast (intragastric, IG). After 21 days, a set of behavioral and biochemical tests were performed in order to assess the degree of memory impairment and neuroinflammation in mice. STZ-infused mice spent less time in the target quadrant of Morris water maze test and took more time to find the shock-free arm in modified Y-maze test, which were rescued in the CysLT1R-knockdowned or pranlukast-treated mice. STZ-induced memory impairment was also accompanied by an elevated level of hippocampal CysLT1R, microglial activation, increased IL-1β, and TNF-α. Such elevation of these factors was found to be mediated through the classical NF-κB pathway and administration of CysLT1R-shRNA or pranlukast for 21 days reversed all these parameters, suggesting a role of CysLT1R in STZ-induced memory deficit and neuroinflammation.