Nitric oxide releasing nanofiber stimulates revascularization in response to ischemia via cGMP-dependent protein kinase.

Nitric oxide (NO) promotes angiogenesis via various mechanisms; however, the effective transmission of NO in ischemic diseases is unclear. Herein, we tested whether NO-releasing nanofibers modulate therapeutic angiogenesis in an animal hindlimb ischemia model. Male wild-type C57BL/6 mice with surgically-induced hindlimb ischemia were treated with NO-releasing 3-methylaminopropyltrimethoxysilane (MAP3)-derived or control (i.e., non-NO-releasing) nanofibers, by applying them to the wound for 20 min, three times every two days. The amount of NO from the nanofiber into tissues was assessed by NO fluorometric assay. The activity of cGMP-dependent protein kinase (PKG) was determined by western blot analysis. Perfusion ratios were measured 2, 4, and 14 days after inducing ischemia using laser doppler imaging. On day 4, Immunohistochemistry (IHC) with F4/80 and gelatin zymography were performed. IHC with CD31 was performed on day 14. To determine the angiogenic potential of NO-releasing nanofibers, aorta-ring explants were treated with MAP3 or control fiber for 20 min, and the sprout lengths were examined after 6 days. As per either LDPI (Laser doppler perfusion image) ratio or CD31 capillary density measurement, angiogenesis in the ischemic hindlimb was improved in the MAP3 nanofiber group; further, the total nitrate/nitrite concentration in the adduct muscle increased. The number of macrophage infiltrations and matrix metalloproteinase-9 (MMP-9) activity decreased. Vasodilator-stimulated phosphoprotein (VASP), one of the major substrates for PKG, increased phosphorylation in the MAP3 group. MAP3 nanofiber or NO donor SNAP (s-nitroso-n-acetyl penicillamine)-treated aortic explants showed enhanced sprouting in an ex vivo aortic ring assay, which was partially abrogated by KT5823, a potent inhibitor of PKG. These findings suggest that the novel NO-releasing nanofiber, MAP3 activates PKG and promotes therapeutic angiogenesis in response to hindlimb ischemia.

Effects of high-gravity acceleration forces and anti-gravity maneuver on the cardiac function of fighter pilots.

The fighter pilots exposed to high gravitational (G) acceleration must perform anti-G maneuvers similar to the Valsalva maneuver. However, the effects of high-G acceleration and anti-G maneuvers on cardiac function have rarely been studied. This study aimed to investigate the effects of high-G forces on cardiac function of fighter pilots. Fighter pilots who underwent regular health check-ups and echocardiography were included (n = 29; 100% men, 41 ± 10 years old; mean flight time, 1821 ± 1186 h). Trainees who had not experienced any flights were included in the control group (n = 16; 100% men, 36 ± 17 years old). Echocardiographic data included left ventricular chamber size, systolic and diastolic functions, right ventricular systolic pressure (RVSP), inferior vena cava (IVC) collapsibility, and tricuspid annular plane systolic excursion (TAPSE). No significant differences in left ventricular ejection fraction, RVSP, or IVC collapsibility were observed between two groups. In the multivariate linear regression analysis with total flight time as an independent continuous variable for fighter pilots, TAPSE was positively correlated with total flight time. The experience of fighter pilots who were exposed to high-G acceleration forces and anti-G maneuvers did not cause cardiac structural changes, but the exposure might be associated with right heart function changes.

Sex-Specific Disparities in Clinical Outcomes After Transcatheter Aortic Valve Replacement Among Different Racial Populations.

Background: Sex-related disparities in clinical outcomes following transcatheter aortic valve replacement (TAVR) and the impact of sex on clinical outcomes after TAVR among different racial groups are undetermined. Objectives: This study assessed whether sex-specific differences in baseline clinical and anatomical characteristics affect clinical outcomes after TAVR and investigated the impact of sex on clinical outcomes among different racial groups. Methods: The TP-TAVR (Trans-Pacific TAVR) registry is a multinational cohort study of patients with severe aortic stenosis who underwent TAVR at 2 major centers in the United States and 1 major center in South Korea. The primary outcome was a composite of death from any cause, stroke, or rehospitalization after 1 year. Results: The incidence of the primary composite outcome was not significantly different between sexes (27.9% in men vs 28% in women; adjusted HR: 0.97; 95% CI: 0.79-1.20). This pattern was consistent in Asian (23.5% vs 23.3%; adjusted HR: 0.99; 95% CI: 0.69-1.41) and non-Asian (30.8% vs 31.6%; adjusted HR: 0.95; 95% CI: 0.72-1.24) cohorts, without a significant interaction between sex and racial group (P for interaction = 0.74). The adjusted risk for all-cause mortality was similar between sexes, regardless of racial group. However, the adjusted risk of stroke was significantly lower in male patients than in female patients, which was more prominent in the non-Asian cohort. Conclusions: Despite significantly different baseline and procedural characteristics, there were no sex-specific differences in the adjusted 1-year rates of primary composite outcomes and all-cause mortality, regardless of different racial groups. (Transpacific TAVR registry [TP-TAVR]; NCT03826264).

Effect of psychosocial factors on autonomic nervous system activity in patients with heart failure.

Autonomic imbalance predicts worse clinical outcomes in patients with heart failure (HF). Managing the variables affecting heart rate variability (HRV) might improve the clinical outcomes of patients with HF. This study aimed to investigate variables affecting HRV. We assessed autonomic nervous system activity (low-frequency [Lf], high-frequency [Hf], and Lf/Hf ratio) in 60 patients with HF, employing standard measures to capture short-term HRV. To estimate the independent effects of variables such as well-known cardiac risk factors and psychosocial conditions on HRV, multivariate analyses were conducted. For psychosocial variables, we assessed depression and quality of life in patients and their family caregivers. We also assessed the self-care behavior of patients and their caregivers' burden. Depression in family caregivers and self-care behavior of patients were independently associated with a decreased Hf (ß-coefficient = 0.309, P = .039 and ß-coefficient = -0.029, P = .047, respectively). Depression of family caregivers and self-care behavior of patients may affect HRV in patients with HF.

Creatine supplementation with exercise reduces α-synuclein oligomerization and necroptosis in Parkinson's disease mouse model.

Parkinson's disease (PD) is an incurable neurological disorder that causes typical motor deficits. In this study, we investigated the effects of creatine supplementation and exercise in the subacute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD. We found that 2% creatine supplementation and/or exercise intervention for 4 weeks elicited neurobehavioral recovery and neuroprotective effects regarding dopaminergic cell loss in MPTP-treated mice; this effect implies functional preservation of dopaminergic cells in the substantia nigra, as reflected by tyrosine hydroxylase expression recovery. Creatine and exercise reduced necroptotic activity in dopaminergic cells by lowering mixed lineage kinase domain-like protein (MLKL) modification to active phenotypes (phosphorylation at Ser345 and oligomerization) and phosphorylated receptor-interacting protein kinase 1 (RIPK1) (Ser166-p) and RIPK3 (Ser232-p) levels. In addition, creatine and exercise reduced the MPTP-induced increase in pathogenic α-synuclein forms, such as Ser129 phosphorylation and oligomerization. Furthermore, creatine and exercise had anti-inflammatory and antioxidative effects in MPTP mice, as evidenced by a decrease in microglia activation, NF-κB-dependent pro-inflammatory molecule expression, and increase in antioxidant enzyme expression. These phenotypic changes were associated with the exercise/creatine-induced AMP-activated protein kinase (AMPK)/nuclear factor erythroid 2-related factor 2 (Nrf2) and sirtuin 3 (SIRT3)/forkhead box O3 (FoxO3a) signaling pathways. In all experiments, combining creatine with exercise resulted in considerable improvement over either treatment alone. Consequently, these findings suggest that creatine supplementation with exercise has anti-inflammatory, antioxidative, and anti-α-synucleinopathy effects, thereby reducing necroptotic cell death in a PD mouse model.

Low- or standard-dose edoxaban versus antiplatelet therapy for leaflet thrombus and cerebral thromboembolism after TAVR: A prespecified analysis of randomized ADAPT-TAVR trial.

BACKGROUND: The risks of leaflet thrombosis and the associated cerebral thromboembolism are unknown according to different anticoagulation dosing after transcatheter aortic valve replacement (TAVR). The aim was to evaluate the incidence of leaflet thrombosis and cerebral thromboembolism between low-dose (30 mg) or standard-dose (60 mg) edoxaban and dual antiplatelet therapy (DAPT) after TAVR. METHODS: In this prespecified subgroup analysis of the ADAPT-TAVR trial, the primary endpoint was the incidence of leaflet thrombosis on 4-dimensional computed tomography at 6-months. Key secondary endpoints were new cerebral lesions on brain magnetic resonance imaging and neurological and neurocognitive dysfunction. RESULTS: Of 229 patients enrolled in this study, 118 patients were DAPT group and 111 were edoxaban group (43 [39.1%] 60 mg vs 68 [61.3%] 30 mg). There was a significantly lower incidence of leaflet thrombosis in the standard-dose edoxaban group than in the DAPT group (2.4% vs 18.3%; odds ratio [OR] 0.11; 95% confidence interval [CI], 0.01-0.55; P = .03). However, no significant difference was observed between low-dose edoxaban and DAPT (15.0% vs 18.3%; OR 0.79; 95% CI, 0.32-1.81; P = .58). Irrespective of different antithrombotic regiments, the percentages of patients with new cerebral lesions on brain MRI and worsening neurological or neurocognitive function were not significantly different. CONCLUSIONS: In patients without an indication for anticoagulation after TAVR, the incidence of leaflet thrombosis was significantly lower with standard-dose edoxaban but not with low-dose edoxaban, as compared with DAPT. However, this differential effect of edoxaban on leaflet thrombosis was not associated with a reduction of new cerebral thromboembolism and neurological dysfunction.

Frequency, Predictors, and Clinical Impact of Valvular and Perivalvular Thrombus After Transcatheter Aortic Valve Replacement.

BACKGROUND: Subclinical aortic valve complex (valvular and perivalvular) thrombus is not rare after transcatheter aortic valve replacement (TAVR). The risk factors and clinical implications of these findings remain uncertain. OBJECTIVES: This study sought to evaluate the frequency, predictors, and clinical outcome of aortic valve complex thrombus after TAVR. METHODS: In the ADAPT-TAVR (Anticoagulation Versus Dual Antiplatelet Therapy for Prevention of Leaflet Thrombosis and Cerebral Embolization After Transcatheter Aortic Valve Replacement) trial comparing edoxaban vs dual antiplatelet therapy in TAVR patients without an indication for chronic anticoagulation, the frequency of valvular (subclinical leaflet thrombus) and perivalvular (supravalvular, subvalvular, and sinus of Valsalva) thrombus was evaluated by 4-dimensional computed tomography at 6 months. The association of these phenomena with new cerebral thromboembolism on brain magnetic resonance imaging, neurologic and neurocognitive dysfunction, and clinical outcomes was assessed. RESULTS: Among 211 patients with 6-month computed tomography evaluations, 91 patients (43.1%) had thrombus at any aortic valve complex, 30 (14.2%) patients had leaflet thrombus, and 78 (37.0%) patients had perivalvular thrombus. A small maximum diameter of the stent at the valve level and low body surface area were independent predictors of aortic valve complex and perivalvular thrombus, and decreased renal function was an independent predictor of leaflet thrombus. No significant differences were observed in new cerebral lesions, neurologic or neurocognitive functions, or clinical outcomes among patients with or without valvular or perivalvular thrombus. CONCLUSIONS: Subclinical aortic valve complex (valvular and perivalvular) thrombus was common in patients who had undergone successful TAVR. However, these imaging phenomena were not associated with new cerebral thromboembolism, neurologic or neurocognitive dysfunction, or adverse clinical outcomes. (Anticoagulation Versus Dual Antiplatelet Therapy for Prevention of Leaflet Thrombosis and Cerebral Embolization After Transcatheter Aortic Valve Replacement [ADAPT-TAVR]; NCT03284827).

Astrocytic Nrf2 Mediates the Neuroprotective and Anti-Inflammatory Effects of Nootkatone in an MPTP-Induced Parkinson's Disease Mouse Model.

This study aims to investigate the neuroprotective effects of nootkatone (NKT), a sesquiterpenoid compound isolated from grapefruit, in an MPTP-induced Parkinson's disease (PD) mouse model. NKT restored MPTP-induced motor impairment and dopaminergic neuronal loss and increased the expression of neurotrophic factors like BDNF, GDNF, and PGC-1α. In addition, NKT inhibited microglial and astrocyte activation and the expression of pro-inflammatory markers like iNOS, TNF-α, and IL-1ß and oxidative stress markers like 4-HNE and 8-OHdG. NKT increased the expression of nuclear factor erythroid 2-related factor 2 (Nrf2)-driven antioxidant enzymes like HO-1 and NQO-1 in astrocytes, but not in neurons or microglia in MPTP-treated mice. To investigate whether Nrf2 mediates the anti-inflammatory, antioxidant, or neuroprotective effects of NKT, mice were pretreated with Nrf2-specific inhibitor brusatol (BT) prior to NKT treatment. BT attenuated the NKT-mediated inhibition of 4-HNE and 8-OHdG and the number of Nrf2+/HO-1+/NQO1+ cells co-localized with GFAP+ astrocytes in the substantia nigra of MPTP-treated mice. In addition, BT reversed the effects of NKT on dopaminergic neuronal cell death, neurotrophic factors, and pro-/anti-inflammatory cytokines in MPTP-treated mice. Collectively, these data suggest that astrocytic Nrf2 and its downstream antioxidant molecules play pivotal roles in mediating the neuroprotective and anti-inflammatory effects of NKT in an MPTP-induced PD mouse model.

Sustained beneficial effect of ß-blockers on clinical outcomes after discontinuation in patients with ST elevation myocardial infarction.

Our previous study demonstrated that beneficial effect of ß-blockers on clinical outcomes in patients with ST elevation myocardial infarction (STEMI). In clinical practice, ß-blocker treatment is occasionally discontinued due to their side effect. The purpose of this study is to assess the impact of discontinuation of ß-blockers on long-term clinical outcomes in patients with STEMI. We analyzed the data and clinical outcomes of 901 patients (716 males, 58 ± 13-year-old) STEMI patients who underwent successful primary percutaneous coronary intervention. At discharge of index STEMI, 598 patients were treated with ß-blockers (491 males, 56 ± 12-year-old). After more than 1-month ß-blocker treatment, ß-blockers were stopped in 188 patients for any reason. We classified patients into continuation of ß-blockers (410 patients, 56 ± 12-year-old) and discontinuation of ß-blockers groups (188 patients, 57 ± 11-year-old) according to discontinuation of ß-blockers. Occurrence of major adverse cardiovascular events (MACEs; death, recurrent MI and target vessel revascularization) during up to 10 years of follow-up was evaluated. Mean follow-up month was 56 ± 28 month. In 132 patients (22%), MACEs were occurred. The MACE-free survival rates in the 2 groups were not statistically different (log-rank P = .461). Adjusted hazard ratio (HR) of discontinuation of ß-blockers for MACEs was 1.006 (95% confidence interval (CI) 0.701-1.445, P = .973; all cause of death, HR = 0.942, 95% CI = 0.547-1.622, P = .828; recurrent MI, HR = 0.476, 95% CI = 0.179-1.262, P = .136; target vessel revascularization, HR = 1.417, 95% CI = 0.865-2.321, P = .166). The MACE-free survival and survival rates of the non ß-blockers treatment group was significantly worse than the discontinuation of ß-blockers group (log-rank P = .003 and < 0.001, respectively). This study demonstrated that discontinuation of ß-blockers was not associated with adverse cardiovascular outcomes after STEMI. The beneficial effect of ß-blockers on clinical outcomes may persist in patients with initial ß-blockers treatment at index STEMI.

Impact of Optimal Medical Therapy on Long-Term Outcomes After Myocardial Revascularization for Multivessel Coronary Disease.

Although optimal medical therapy (OMT) after coronary revascularization is advocated for intensive secondary prevention, its criteria and effect on long-term outcomes are uncertain. Using data from the ASAN-Multivessel (Asan Medical Center-Multivessel Revascularization) registry, we identified 8,311 patients who underwent coronary artery bypass grafting (CABG) (n = 3,115) or percutaneous coronary intervention (PCI) (n = 5,196). OMT was defined as the combination of minimum of 3 medications in 4 drug classes (antiplatelet drugs, statins, ß blockers, and angiotensin-converting enzyme inhibitors or angiotensin receptor blockers). Two primary outcomes were all-cause mortality and serious composite outcome of death, spontaneous myocardial infarction, or stroke at 10 years. Of 8,311 patients, 4,321 (52.0%) followed OMT. In the 3,397 propensity-score-matched cohort, OMT status compared with non-OMT status was significantly associated with a lower risk of all-cause mortality (10.7% vs 18.7%; hazard ratio [HR] 0.55, 95% confidence interval [CI] 0.47 to 0.65) and serious composite outcome (14.5% vs 22.5%, HR 0.635, 95% CI 0.55 to 0.73) at 10 years. The association on 10-year mortality was more prominent in the PCI group (HR 0.45, 95% CI 0.36 to 0.56) than in the CABG group (HR 0.72, 95% CI 0.58 to 0.90) with a significant interaction (p = 0.001). Overall findings were consistent using different OMT criteria (all 4 types of medications). In conclusion, OMT significantly lowered the risks of mortality and major cardiovascular events at 10 years in patients with multivessel revascularization. The OMT impact on mortality was more remarkable in the PCI group than in the CABG group. This work was registered at http://ClinicalTrials.gov (Identifier: NCT02039752).

Validation of Academic Research Consortium for High Bleeding Risk Definition in East-Asian Patients.

Background: Clinical applicability of the Academic Research Consortium High Bleeding Risk (ARC-HBR) criteria in East-Asian patients receiving potent antiplatelet therapy for acute coronary syndromes (ACS) is still undetermined. Objectives: The purpose of this study was to validate the ARC definition for HBR in East-Asian patients with ACS for invasive management. Methods: We analyzed data from the TICAKOREA (Ticagrelor Versus Clopidogrel in Asian/Korean Patients With ACS Intended for Invasive Management) trial and randomly assigned 800 Korean ACS subjects to receive, in a 1:1 ratio, ticagrelor or clopidogrel. Patients were considered HBR if they met at least 1 major or 2 minor ARC-HBR criteria. The primary bleeding endpoint was Bleeding Academic Research Consortium 3 or 5 bleeding and the primary ischemic endpoint was a major adverse cardiovascular event (MACE) (a composite of cardiovascular death, myocardial infarction, or stroke) at 12 months. Results: Among 800 randomized patients, 129 (16.3%) were categorized HBR patients. HBR patients, compared with non-HBR patients, had a higher incidence of Bleeding Academic Research Consortium 3 or 5 bleeding (10.0% vs 3.7%; HR: 2.98; 95% CI: 1.52-5.86; P < 0.001) and MACE (14.3% vs 6.1%; HR: 2.35; 95% CI: 1.35-4.10; P = 0.002). The relative treatment effect of ticagrelor or clopidogrel on primary bleeding and ischemic outcomes were different between each group. Conclusions: This study validates the ARC-HBR definition in Korean ACS patients. Approximately 15% of patients qualified as HBR patients who were at increased risk not only for bleeding but also for thrombotic events. The clinical application of ARC-HBR to determine the relative effect of different antiplatelet regiments should be further investigated. (Safety and Efficacy of Ticagrelor Versus Clopidogrel in Asian/KOREAn Patients with Acute Coronary Syndromes Intended for Invasive Management [TICA KOREA]; NCT02094963).

Race-Specific Impact of Conventional Surgical Risk Score on 1-Year Mortality After Transcatheter Aortic Valve Replacement.

Background: Interracial differences in the distribution and prognostic value of conventional Society of Thoracic Surgeons (STS) score on long-term mortality after transcatheter aortic valve replacement (TAVR) are uncertain. Objectives: This study aims to compare the impact of STS scores on clinical outcomes at 1-year after TAVR between Asian and non-Asian populations. Methods: We used the Trans-Pacific TAVR (TP-TAVR) registry, a multinational multicenter, observational registry involving patients undergoing TAVR at 2 major centers in the United States and 1 major center in Korea. Patients were classified into 3 groups (low, intermediate, and high-risk) according to the STS score and compared between STS risk groups and race. The primary outcome was all-cause mortality at 1-year. Results: Among 1,412 patients, 581 were Asian and 831 were non-Asian. The distribution of the STS risk score group was different between Asian and non-Asian groups (62.5% low-, 29.8% intermediate-, and 7.7% high-risk in Asian vs 40.6% low-, 39.1% intermediate-, and 20.3% high-risk in non-Asian). In the Asian population, the all-cause mortality at 1-year was substantially higher in the high-risk STS group than in the low- and intermediate-risk groups (3.6% low-risk, 8.7% intermediate-risk, and 24.4% high-risk; log-rank P < 0.001), which was primarily driven by noncardiac mortality. In the non-Asian group, there was a proportional increase in all-cause mortality at 1-year according to the STS risk category (5.3% low-risk, 12.6% intermediate-risk, and 17.8% high-risk; log-rank P < 0.001). Conclusions: In this multiracial registry of patients with severe aortic stenosis who underwent TAVR, we identified a differential proportion and prognostic impact of STS score on 1-year mortality between Asian and non-Asian patients (TP-TAVR [Transpacific TAVR Registry]; NCT03826264).

Suppression of neuroinflammation and α-synuclein oligomerization by rotarod walking exercise in subacute MPTP model of Parkinson's disease.

Parkinson's disease (PD) belongs to an α-synucleinopathy and manifests motor dysfunction attributed to nigrostriatal dopaminergic degeneration. In clinical practice, the beneficial role of physical therapy such as motor skill learning training has been recognized in PD-linked motor defects. Nevertheless, the disease-modifying effects of motor skill learning training on PD-related pathology remain unclear. Here, we investigated the disease-modifying effects of rotarod walking exercise (RWE), a modality of motor skill learning training, in a subacute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD. In motor function and dopaminergic degeneration, RWE improved MPTP-induced deficits. In addition, RWE enhanced the expression of neurotrophic factors BDNF/GDNF, PGC1-α, Nurr1, and p-AMPK, thereby recovering dopaminergic neuronal cell death. Moreover, RWE inhibited microglial activation and the expression of pro-inflammatory markers, such as p-IκBα, iNOS, IL-1ß, TNF-α, and cathepsin D, while elevating anti-inflammatory IL-10 and TGF-ß. RWE also decreased oxidative stress markers in the substantia nigra, such as 4-HNE and 8-OHdG-positive cells, while increasing Nrf2-controlled antioxidant enzymes. Regarding the effect of RWE on α-synuclein, it reduced the monomer/oligomer forms of α-synuclein and phosphorylation at serine 129. Further mechanistic studies revealed that RWE suppressed the expression of matrix metalloproteinase-3 and p-GSK3ß (Y216), which play key roles in α-synuclein aggregation. These data collectively suggest that inhibition of neuroinflammation and α-synuclein oligomerization by RWE may contribute to the improvement of PD pathology.

RIPK1 Regulates Microglial Activation in Lipopolysaccharide-Induced Neuroinflammation and MPTP-Induced Parkinson's Disease Mouse Models.

Increasing evidence suggests a pivotal role of receptor-interacting protein kinase 1 (RIPK1), an initiator of necroptosis, in neuroinflammation. However, the precise role of RIPK1 in microglial activation remains unclear. In the present study, we explored the role of RIPK1 in lipopolysaccharide (LPS)-induced neuroinflammation and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD model mice by using RIPK1-specific inhibitors necrostatin-1 (Nec-1) and necrostatin-1 stable (Nec-1s). Nec-1/Nec-1s or RIPK1 siRNA inhibited the production of proinflammatory molecules and the phosphorylation of RIPK1-RIPK3-MLKL and cell death in LPS-induced inflammatory or LPS/QVD/BV6-induced necroptotic conditions of BV2 microglial cells. Detailed mechanistic studies showed that Nec-1/Nec-1s exerted anti-inflammatory effects by modulating AMPK, PI3K/Akt, MAPKs, and NF-κB signaling pathways in LPS-stimulated BV2 cells. Subsequent in vivo studies showed that Nec-1/Nec-1s inhibited microglial activation and proinflammatory gene expression by inhibiting the RIPK1 phosphorylation in the brains of LPS-injected mice. Furthermore, Nec-1/Nec-1s exert neuroprotective and anti-inflammatory effects in MPTP-induced PD mice. We found that p-RIPK1 is mainly expressed in microglia, and thus RIPK1 may contribute to neuroinflammation and subsequent cell death of dopaminergic neurons in MPTP-induced PD model mice. These data suggest that RIPK1 is a key regulator of microglial activation in LPS-induced neuroinflammation and MPTP-induced PD mice.