NLRP3 inflammasome inhibitor(Exscientia/University of Oxford)

Cardiac hypertrophy is a leading risk factor for cardiovascular morbidity and mortality. Alpha-protein kinase 1 (ALPK1) is a novel essential player in innate immunity and inflammation. Therapeutic agents targeting ALPK1 have successively entered clinical trials and become research hotspots. However, the role of ALPK1 on cardiac hypertrophy remains unknown.

In the present study, transverse aortic constriction (TAC) was used to establish in vivo models of cardiac hypertrophy. Neonatal mouse cardiomyocytes (NMCMs) and AC16 human cardiomyocytes treated with angiotensin Ⅱ (Ang Ⅱ) were performed to mimic in vitro models of cardiac hypertrophy. ALPK1 gene expression was knocked down by small interfering RNAs (siRNAs) and overexpressed by transfection with plasmid, respectively.

ALPK1 was significantly upregulated in cardiac hypertrophy. ALPK1 knockdown effectively suppressed Ang Ⅱ-induced upregulated hypertrophic markers, enlarged cell surface area, decreased cell viability, increased lactate dehydrogenase release, enhanced caspase-1 activity, elevated positive pyroptotic cells, as well as the upregulation of p-NF-κB p65, NLRP3 inflammasome and pyroptosis markers in both NMCMs and AC16 cells. ALPK1 knockdown markedly suppressed the increased secretion of IL-1β and IL-18 induced by Ang Ⅱ in NMCMs. Consistently, ALPK1 over-expression significantly increased the expression of hypertrophic markers, enhanced the cell surface area, elevated the number of pyroptotic cells, upregulated the protein expression of NLRP3 inflammasome and pyroptosis markers, increased the secretion of IL-1β and IL-18, which were successfully reversed by the addition of MCC950, a selective NLRP3 inflammasome inhibitor. However, MCC950 treatment showed no effect on the upregulation of ALPK1 and p-NF-κB p65 induced by ALPK1 over-expression.

ALPK1 promotes cardiomyocyte hypertrophy by activating NF-κB/NLRP3 inflammasome-mediated pyroptosis, providing new potential applications for agents targeting ALPK1 in the immunotherapy of cardiac hypertrophy.

Quercetin (Qur), as a natural plant-derived flavonoid with antioxidant and neuroprotective properties, and MCC950, a selective NLRP3 inflammasome inhibitor, have each demonstrated notable pharmacological activities, including antioxidant and anti-inflammatory effects. The present study examined the combined impacts of Qur and MCC950 on oxidative stress, demyelination, and inflammation in the cuprizone (CPZ)-induced demyelination model. To induce demyelination, CPZ (0.2% w/w) was incorporated into the normal diet of male C57BL/6 mice for 42 days. Subsequently, animals received Qur (25 mg/kg/day, oral), MCC950 (5 mg/kg/day, i.p), or their combination for 14 days. Working memory was evaluated using the Y-maze test. FluoroMyelin staining and GFAP immunofluorescence were used to assess the extent of demyelination and astrocyte activation, respectively. Oxidative stress and antioxidant biomarkers, including MDA, TOS, TAC, SOD, CAT, and GPx, were measured using colorimetric techniques. The expression levels of oligodendrocyte markers, antioxidant signaling, and pro-inflammatory cytokines, including MBP, PDGFRα, Olig2, Nrf2, HO-1, NQO1, GSK3β, IL-1β, IL-18, and TNF-α, were assessed by qRT-PCR. Our results indicated that co-administration of Qur and MCC950 improved working memory and restored antioxidant capacity. A significant reduction was found in the extent of demyelination, astrocytic reactivity, and inflammatory mediator expression in treated mice. Moreover, combined treatment elevated the expression levels of pro-myelinating and antioxidant markers more effectively than either agent alone. Our findings indicate that inhibiting the NLRP3 inflammasome and enhancing antioxidant defenses promote remyelination and confer neuroprotective effects by reducing oxidative stress and inflammation, likely through modulation of glial responses.