Phenothiazine Inhibits Neuroinflammation and Inflammasome Activation Independent of Hypothermia After Ischemic Stroke

Abstract

A depressive or hibernation-like effect of chlorpromazine and promethazine (C + P) on brain activity was reported to induce neuroprotection, with or without induced-hypothermia. However, the underlying mechanisms remain unclear. The current study evaluated the pharmacological function of C + P on the inhibition of neuroin ammatory response and in ammasome activation after ischemia/reperfusion. A total of 72 adult male Sprague-Dawley rats were subjected to 2 h middle cerebral artery occlusion (MCAO) followed by 6 or 24 h reperfusion. At the onset of reperfusion, rats received C + P (8 mg/kg) with temperature control. Brain cell death was detected by measuring CD68 and myeloperoxidase (MPO) levels. In ammasome activation was measured by mRNA levels of NLRP3, IL-1β, and TXNIP, and protein quantities of NLRP3, IL-1β, TXNIP, cleaved-Caspase-1, and IL-18. Activation of JAK2/STAT3 pathway was detected by the phosphorylation of STAT3 (p-STAT3) and JAK2 (p-JAK2), and the co-localization of p-STAT3 and NLRP3. Activation of the p38 pathway was assessed with the protein levels of p-p38/p38.The mRNA and protein levels of HIF-1α, FoxO1, and p-FoxO1, and the co-localization of p-STAT3 with HIF-1α or FoxO1 were quantitated. As expected, C + P signi cantly reduced cell death and attenuated the neuroin ammatory response as determined by reduced CD68 and MPO. C + P decreased ischemiainduced in ammasome activation, shown by reduced mRNA and protein expressions of NLRP3, IL-1β, TXNIP, cleaved-Caspase-1, and IL-18. Phosphorylation of JAK2/STAT3 and p38 pathways and the colocalization of p-STAT3 with NLRP3 were also inhibited by C + P. Furthermore, mRNA levels of HIF-1α and FoxO1 were decreased in the C + P group. While C + P inhibited HIF-1α protein expression, it increased FoxO1 phosphorylation, which promoted the exclusion of FoxO1 from the nucleus and inhibited FoxO1 activity. At the same time, C + P reduced the co-localization of p-STAT3 with HIF-1α or FoxO1. In conclusion, C + P treatment conferred neuroprotection in stroke by suppressing neuroin ammation and NLRP3 in ammasome activation. The present study suggests that JAK2/STAT3/p38/HIF-1α/FoxO1 are vital regulators and potential targets for e cacious therapy following ischemic stroke.

Focus on the role of mitochondria in NLRP3 inflammasome activation: A prospective target for the treatment of ischemic stroke (Review)

“…Upon stroke attack, the interruption and reperfusion of blood flow in the brain tissue trigger the infiltration of inflammatory cells to induce neuronal death ( 60 ). Neuroinflammation is a primary pathological event involved in the process of ischemic injury and repair ( 61 ).…”

Novel small molecules inhibit proteotoxicity and inflammation: Mechanistic and therapeutic implications for Alzheimer’s Disease, healthspan and lifespan- Aging as a consequence of glycolysis

“…Tricyclic compounds constitute the major class of drugs to treat psychosis and depression [90]. The combination of two tricylic antipsychotic phenothiazines, chlorpromazine and promethazine, is reported to be neuroprotective in a rat model of stroke associated with reduction in neuroinflammation [91,92]. It is of particular interest that this reduction in neuroinflammation appears to be mediated by a reduction in "hyperglycolysis" [93] since reduction of glycolysis appears to play a major role in mediating the protective effects of dietary restriction during aging [13,[94][95][96].…”

Stellate ganglion block ameliorated central post-stroke pain with comorbid anxiety and depression through inhibiting HIF-1α/NLRP3 signaling following thalamic hemorrhagic stroke

“…We further found that pharmacological inhibition of thalamic HIF-1α and NLRP3 prevented peri-thalamic lesion site glial activation and inflammatory cytokine upregulation, demonstrating that HIF-1α/NLRP3 signaling causes the inflammatory response after thalamic hemorrhagic stroke. Actually, the HIF-1α/NLRP3 pathway has been recognized as a potential molecular target for treating ischemic stroke and traumatic brain injury because it regulates microglia activation and inflammatory cytokines release in the inflammatory cascade after brain injury [ 17 , 47 , 48 ]. Oxidative stress, a change in the pro-oxidant/antioxidant balance that promotes oxidation, also leads to stroke-related brain injury [ 49 , 50 ].…”