Piperlongumine Is an NLRP3 Inhibitor With Anti-inflammatory Activity

Piperlongumine (PL) is an alkaloid from Piper longum L. with anti-inflammatory and antitumor properties. Numerous studies have focused on its antitumor effect. However, the underlying mechanisms of its anti-inflammation remain elusive. In this study, we have found that PL is a natural inhibitor of Nod-like receptor family pyrin domain-containing protein-3 (NLRP3) inflammasome, an intracellular multi-protein complex that orchestrates host immune responses to infections or sterile inflammations. PL blocks NLRP3 activity by disrupting the assembly of NLRP3 inflammasome including the association between NLRP3 and NEK7 and subsequent NLRP3 oligomerization. Furthermore, PL suppressed lipopolysaccharide-induced endotoxemia and MSU-induced peritonitis in vivo, which are NLRP3-dependent inflammation. Thus, our study identified PL as an inhibitor of NLRP3 inflammasome and indicated the potential application of PL in NLRP3-relevant diseases.

Characterization of the PLN p.Arg14del Mutation in Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes

Phospholamban (PLN) is the natural inhibitor of the sarco/endoplasmic reticulum Ca2+ ATP-ase (SERCA2a). Heterozygous PLN p.Arg14del mutation is associated with an arrhythmogenic dilated cardiomyopathy (DCM), whose pathogenesis has been attributed to SERCA2a “superinhibition”. Aim: To test in cardiomyocytes (hiPSC-CMs) derived from a PLN p.Arg14del carrier whether (1) Ca2+ dynamics and protein localization were compatible with SERCA2a superinhibition and (2) if functional abnormalities could be reverted by pharmacological SERCA2a activation (PST3093). Methods: Ca2+ transients (CaT) were recorded at 36 °C in hiPSC-CMs clusters during field stimulation. SERCA2a and PLN where immunolabeled in single hiPSC-CMs. Mutant preparations (MUT) were compared to isogenic wild-type ones (WT), obtained by mutation reversal. Results: WT and MUT differed for the following properties: (1) CaT time to peak (tpeak) and half-time of CaT decay were shorter in MUT; (2) several CaT profiles were identified in WT, “hyperdynamic” ones largely prevailed in MUT; (3) whereas tpeak rate-dependently declined in WT, it was shorter and rate-independent in MUT; (4) diastolic Ca2+ rate-dependently accumulated in WT, but not in MUT. When applied to WT, PST3093 turned all the above properties to resemble those of MUT; when applied to MUT, PST3093 had a smaller or negligible effect. Preferential perinuclear SERCA2a-PLN localization was lost in MUT hiPSC-CMs. Conclusions: Functional data converge to argue for PLN p.Arg14del incompetence in inhibiting SERCA2a in the tested case, thus weakening the rationale for therapeutic SERCA2a activation. Mechanisms alternative to SERCA2a superinhibition should be considered in the pathogenesis of DCM, possibly including dysregulation of Ca2+-dependent transcription.

SERCA2a gain of function in patient-derived R14Del hiPSC-CMs

Phospholamban (PLN) is the natural inhibitor of the sarco/endoplasmic reticulum Ca2+ ATPase (SERCA2a). Heterozygous PLN-R14del mutation is associated with an arrhythmogenic dilated cardiomyopathy (DCM), whose pathogenesis has been attributed to SERCA2a “superinhibition.” The aim of the project is to test in human induced pluripotent stem cell–derived cardiomyocytes (hiPSC-CM) harvested from a PLN-R14del carrier whether (1) Ca2+ dynamics and protein localization were compatible with SERCA2a superinhibition and (2) functional abnormalities could be reverted by pharmacological SERCA2a activation with PST3093. Ca2+ transients (CaT) were recorded at 36°C in hiPSC-CMs clusters during field stimulation. SERCA2a and PLN were immunolabeled in single hiPSC-CMs. Mutant (MUT) preparations were compared with isogenic WT ones obtained by mutation reversal. WT and MUT differed for the following properties: (1) CaT time to peak (tpeak) and half-time of CaT decay were shorter in MUT, (2) several CaT profiles were identified in WT, whereas “hyperdynamic” ones largely prevailed in MUT, (3) whereas tpeak rate-dependently declined in WT, it was shorter and rate independent in MUT, and (4) diastolic Ca2+ rate-dependently accumulated in WT, but not in MUT. When applied to WT, PST3093 changed all of the above properties to resemble those of MUT; when applied to MUT, PST3093 had no effect. Preferential perinuclear SERCA2a-PLN localization was lost in MUT hiPSC-CMs. In conclusion, functional data converge to argue for PLN-R14del incompetence in inhibiting SERCA2a in the tested case, thus weakening the rationale for therapeutic SERCA2a activation. Mechanisms alternative to SERCA2a superinhibition should be considered in the pathogenesis of DCM, including dysregulation of Ca2+-dependent transcription.

Increased 20-HETE Signaling Suppresses Capillary Neurovascular Coupling After Ischemic Stroke in Regions Beyond the Infarct

Neurovascular coupling, the process by which neuronal activity elicits increases in the local blood supply, is impaired in stroke patients in brain regions outside the infarct. Such impairment may contribute to neurological deterioration over time, but its mechanism is unknown. Using the middle cerebral artery occlusion (MCAO) model of stroke, we show that neuronal activity-evoked capillary dilation is reduced by ∼75% in the intact cortical tissue outside the infarct border. This decrease in capillary responsiveness was not explained by a decrease in local neuronal activity or a loss of vascular contractility. Inhibiting synthesis of the vasoconstrictive molecule 20-hydroxyeicosatetraenoic acid (20-HETE), either by inhibiting its synthetic enzyme CYP450 ω-hydroxylases or by increasing nitric oxide (NO), which is a natural inhibitor of ω-hydroxylases, rescued activity-evoked capillary dilation. The capillary dilation unmasked by inhibiting 20-HETE was dependent on PGE2 activation of endoperoxide 4 (EP4) receptors, a vasodilatory pathway previously identified in healthy animals. Cortical 20-HETE levels were increased following MCAO, in agreement with data from stroke patients. Inhibition of ω-hydroxylases normalized 20-HETE levels in vivo and increased cerebral blood flow in the peri-infarct cortex. These data identify 20-HETE-dependent vasoconstriction as a mechanism underlying capillary neurovascular coupling impairment after stroke. Our results suggest that the brain’s energy supply may be significantly reduced after stroke in regions previously believed to be asymptomatic and that ω-hydroxylase inhibition may restore healthy neurovascular coupling post-stroke.

THE EXTRACTION OF EUCALYPTUS AS A NATURAL INHIBITOR FOR MILD STEEL IN HCL MEDIUM

This work concern with the electrochemical study related to eucalyptus leaves extract utilized as inhibitor towards mild steel' corrosion in various concentrations of HCl, at a temperature comparable to the average temperature in Iraq, at a temperature of 25°C.Electrochemical impedance spectroscopy and electrochemical polarization test methods were used to investigate this. The extract inhibition efficiencies and mild steel corrosion rate were calculated. The results show that the extract may be utilized as one of the effective inhibitors to prevent mild steel corrosion. The maximal efficiency of inhibition has been 99.77% at a concentration of 0.5 molarity, and the inhibition efficiency decreased with the increase in HCl concentration.

An Innovative Prosopis Cineraria Pod Aqueous Waste as Natural Inhibitor for Enhancing Unsaturated Lipids Production in Yeast Cell Using Banana Peel

Single cell oil (SCO) produced by yeast is an attractive alternative due to higher lipid yield in a limited space with naturally manipulating the quality. In the present study, the banana peel is used as a source of carbon for biotransformation by Rhodotorula mucilaginosa to lipid. Further, the quality and quantity of the lipid are enhanced using discarded aqueous Prosopis cinerareia pod extract as a natural inhibitor. P. cineraria aqueous extract was quantified using HPLC, and it was contained phenyl propenoids such as epicatechin (0.068%), gallic acid (0.29%), quercetin (0.34%), epigallocatechin (0.091%), rutin (0.141%), ellagic acid (0.141%), along with glucose (1.22%), and sucrose (2.36%). The sucrose and glucose were isolated from the aqueous extract, and further characterized through NMR and TGA. Hence, this natural inhibitor is found advantageous as compared to the chemical inhibitor (statin) in terms of lipid production with desirable quality. It is achieved by inhibitors blocking the yeast competitive mevalonate pathway to promote higher lipid accumulation in the microbial cells. The anti-chlostrolemic activity of this natural inhibitor might be influenced lipid accumulation by blocking the mevalonate pathway. Thus, the reducing sugars as well as phenylpropenoids were worked in synergy to enhance accumulation of unsaturated lipid in the microbial cells. Phenylpropenoids may inhibit the key enzyme HMG reductase, which controls the mevalonate pathway for ergosterol formation to induce lipid accumulation. This lipid isolation from yeast cell was improved using green solvent viz. liquid-CO2. This lquid-CO2extract was enriched with unsaturated lipid (46.96%) including w-fatty acids such as linoleic (17.61%) and linolenic (5.35%). Thus, the SCO is produced using food waste as the source of carbon as well as an inhibitor, and this lipid is treated as natural to find suitable for nutritional purposes.

Increased 20-HETE signaling suppresses neurovascular coupling after ischemic stroke in regions beyond the infarct

Neurovascular coupling, the process by which neuronal activity elicits increases in the local blood supply, is impaired in stroke patients in brain regions outside the infarct. Such impairment may contribute to neurological deterioration over time, but its mechanism is unknown. Using the middle cerebral artery occlusion (MCAO) model of stroke, we show that neuronal activity-evoked capillary dilation is reduced by ~75% in the intact cortical tissue outside the infarct border. This decrease in capillary responsiveness was not explained by a decrease in local neuronal activity or a loss of vascular contractility. Inhibiting synthesis of the vasoconstrictive molecule 20-HETE, either by inhibiting its synthetic enzyme CYP450 ω-hydroxylases or by increasing nitric oxide (NO), which is a natural inhibitor of ω-hydroxylases, rescued activity-evoked capillary dilation. The capillary dilation unmasked by inhibiting 20-HETE was dependent on PGE2 activation of EP4 receptors, a vasodilatory pathway previously identified in healthy animals. Cortical 20-HETE levels were increased following MCAO, in agreement with data from stroke patients. Inhibition of ω-hydroxylases normalized 20-HETE levels in vivo and increased cerebral blood flow in the peri-infarct cortex. These data identify 20-HETE-dependent vasoconstriction as a mechanism underlying neurovascular coupling impairment after stroke. Our results suggest that the brain's energy supply may be significantly reduced after stroke in regions previously believed to be asymptomatic and that ω-hydroxylase inhibition may restore healthy neurovascular coupling post-stroke.