JNK-IN-8 treatment improves ARDS-induced cognitive impairment by inhibiting JNK/NF-κB-mediated NLRP3 inflammasome

PURPOSE

Cognitive impairment is a critical complication of acute respiratory distress syndrome (ARDS). However, effective interventions are lacking. Growing evidence demonstrates that c-Jun N-terminal kinase (JNK)-mediated neuroinflammation is involved in the development of ARDS. Therefore, we hypothesized that the JNK pathway is involved in ARDS-induced cognitive impairment.

METHODS

An in vivo rat model of ARDS was established by treating it with lipopolysaccharide. The cognitive function was assessed by behavioral tests. The levels of pro-inflammatory cytokines, JNK and NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) were analyzed by enzyme-linked immunosorbent assay, western blot, or immunohistochemical analysis.

RESULTS

We found that JNK inhibitor 8 (JNK-IN-8) alleviated cognitive impairment, neuroinflammation, and NLRP3 inflammasome activation in the ARDS rat model. Additionally, an in vivo study showed that the protective effect of JNK-IN-8 on cognitive impairment was blocked by nigericin, an NLRP3 activator.

CONCLUSIONS

Our data suggest that JNK-IN-8 treatment improves ARDS-induced cognitive impairment by inhibiting the JNK/nuclear factor-κB-mediated NLRP3 inflammasome.

JNK-IN-8, a c-Jun N-terminal kinase inhibitor, improves functional recovery through suppressing neuroinflammation in ischemic stroke

C‐Jun N‐terminal kinase (JNK) is a pivotal MAPK (mitogen‐activated protein kinase), which activated by ischemia brain injury and plays a fairly crucial function in cerebral ischemic injury. Emerging studies demonstrated that JNK‐IN‐8 (a JNK inhibitor with high specificity) regulates traumatic brain injury through controlling neuronal apoptosis and inflammation. However, the function of JNK‐IN‐8 in ischemic stroke and the mechanisms underlying of JNK‐IN‐8 about neuroprotection are not well understood. In this work, male rats were treated with JNK‐IN‐8 after transient middle cerebral artery occlusion, and then the modified improved neurological function score (mNSS), the foot‐fault test (FFT), interleukin‐1β (IL‐1β), IL‐6, and tumor necrosis factor‐α (TNF‐α) levels were assessed. We found that JNK‐IN‐8‐treated rats with MCAO exerted an observable melioration in space learning as tested by the improved mNSS, and showed sensorimotor functional recovery as measured by the FFT. JNK‐IN‐8 also played anti‐inflammatory roles as indicated through decreased activation of microglia and decreased IL‐6, IL‐1β, and TNF‐α expression. Furthermore, JNK‐IN‐8 suppressed the activation of JNK and nuclear factor‐κB (NF‐κB) signaling as indicated by the decreased level of phosphorylated‐JNK and p65. All data demonstrate that JNK‐IN‐8 inhibits neuroinflammation and improved neurological function by inhibiting JNK/NF‐κB and is a promising agent for the prevention of ischemic brain injury.