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Extracellular ASC exacerbated the recurrent ischemic stroke in an NLRP3-dependent manner.

ABSTRACT: Using a photothrombotic mouse model of single stroke, we show that a single stroke onset increases the nuclear factor-κB (NF-κB), NLR family CARD domain containing protein 4 (NLRC4), and absent in melanoma 2 (AIM2) inflammasomes, as well as the mRNA levels of NLRP3. Next, using a photothrombotic mouse model of recurrent stroke, we found that recurrent strokes increased the activation of NLRP3, exacerbated the brain damage and the pro-inflammatory response in wild type (WT) mice, but not in NLRP3 knockout (NLRP3 KO) mice. Additionally, we found that apoptosis-associated speck-like protein containing a CARD (ASC) protein level surrounding the infarct area was comparatively increased, but that ASC specks outside of microglia in both the ipsilateral and contralateral of stroke site were decreased in NLRP3 KO mice relative to wild-type (WT) controls, and the number of ASC specks surrounding the second infarct area was positively correlated to the damage scores. Mechanistically, we found that recombinant ASC (RecASC) activated NLRP3 and induced pro-inflammatory responses, exacerbating the outcome of ischemic stroke, in WT mice, but not in NLRP3 KO mice. We therefore conclude that the NLRP3 inflammasome is activated by two attacks of stroke, which act together with ASC to exacerbate recurrent strokes.

SUBMITTER: He XF

PROVIDER: S-EPMC7181081 | biostudies-literature | 2020 May

REPOSITORIES: biostudies-literature

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Extracellular ASC exacerbated the recurrent ischemic stroke in an NLRP3-dependent manner.

He Xiao-Fei XF Zeng Yi-Xuan YX Li Ge G Feng Yu-Kun YK Wu Cheng C Liang Feng-Yin FY Zhang Yu Y Lan Yue Y Lan Yue Y Xu Guang-Qing GQ Pei Zhong Z

Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism 20190619 5

Using a photothrombotic mouse model of single stroke, we show that a single stroke onset increases the nuclear factor-κB (NF-κB), NLR family CARD domain containing protein 4 (NLRC4), and absent in melanoma 2 (AIM2) inflammasomes, as well as the mRNA levels of NLRP3. Next, using a photothrombotic mouse model of recurrent stroke, we found that recurrent strokes increased the activation of NLRP3, exacerbated the brain damage and the pro-inflammatory response in wild type (WT) mice, but not in NLRP3 ...[more]

PMID: 31216943

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Project description:BackgroundSex differences in stroke outcomes have been noted, but whether this extends to stroke recurrence is unclear. We examined sex differences in recurrent stroke using data from the Platelet-Oriented Inhibition in New TIA and Minor Ischemic Stroke (POINT) trial.Patients and methodsWe assessed the risk of recurrent stroke in women compared to men using data from the POINT trial. Adults >18 years old were randomized within 12 hours of onset of minor ischemic stroke or transient ischemic attack (TIA), and followed for up to 90 days for ischemic stroke, our primary outcome. We used Cox proportional hazards model adjusted for demographics and stroke risk factors to evaluate the association between sex and stroke recurrence. We used interaction term testing and prespecified subgroup analyses to determine if the association between sex and recurrent stroke differed by age (<60 versus >60 years old), locale (US versus non-US), and index event type (stroke versus TIA). Last, we evaluated whether sex modified the effect of common stroke risk factors on stroke recurrence.ResultsOf 4,881 POINT trial participants with minor stroke or high-risk TIA, 2,195 (45%) were women. During the 90-day follow-up period, 267 ischemic strokes occurred; 121 were in women and 146 in men. The cumulative risk of recurrent ischemic stroke was not significantly different among women (5.76%; 95% CI, 4.84%-6.85%) compared to men (5.67%; 95% CI, 4.83%-6.63%). Women were not at a different risk of recurrent ischemic stroke compared to men (hazard ratio [HR], 1.02; 95% CI, 0.80-1.30) in unadjusted models or after adjusting for covariates. However, there was a significant interaction of age with sex (P=0.04). Among patients <60 years old, there was a non-significantly lower risk of recurrent stroke in women compared to men (HR 0.66; 95% CI 0.42-1.05). Last, sex did not modify the association between common stroke risk factors and recurrent stroke risk.Discussion and conclusionAmong patients with minor stroke or TIA, the risk of recurrent ischemic stroke and the impact of common stroke risk factors did not differ between men and women.

Project description:BackgroundHypertension is a common comorbidity of osteoarthritis (OA) with known autonomic dysregulation; thus, the autonomic nervous system may provide a shared underlying mechanism. The objective of this study was to examine the role of the autonomic nervous system in a preclinical model of OA and hypertension.MethodsExperiments were conducted in spontaneously hypertensive rats and a normotensive control strain, including male and female rats. OA was surgically induced via medial meniscus transection with skin incision used as a sham control (n = 7-8/strain/sex/surgery). Tactile sensitivity, anxiety-related behavior, and serum corticosterone were measured at baseline then bi-weekly across 8 weeks. At weeks 9-10, cardiovascular responses to a chemical vagal nerve agonist were determined to indirectly evaluate vagus nerve function. The joint structure was assessed via grading of histological sections.ResultsIn males, OA resulted in thinner cartilage in both hypertensive (OA vs. non-OA p < 0.001) and normotensive (OA vs. non-OA p < 0.001). Only females with comorbid hypertension and OA displayed thinner cartilage (p = 0.013). Male hypertensive OA animals had increased calcified subchondral bone compared to normotensive OA animals (p = 0.043) while female hypertensive OA animals had increased calcified subchondral bone compared to hypertensive sham animals (p < 0.001). All MCLT+MMT groups developed low-grade synovitis; interestingly, hypertensive OA females had higher synovitis scores than normotensive OA females (p = 0.046). Additionally, hypertension led to larger drops in blood pressure with vagal activation in both OA (hypertensive vs. normotensive p = 0.018) and sham (hypertensive vs. normotensive p < 0.001) male animals. In females, this trend held true only in OA animals (normotensive vs. hypertensive p = 0.005).ConclusionThese data provide preliminary evidence that hypertension influences OA progression and encourages further study into the autonomic nervous system as a possible mechanism.

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Extracellular ASC exacerbated the recurrent ischemic stroke in an NLRP3-dependent manner.

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Extracellular ASC exacerbated the recurrent ischemic stroke in an NLRP3-dependent manner.

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