Palmitic acid methyl ester is a novel neuroprotective agent against cardiac arrest

The role of serum/glucocorticoid-regulated kinase 1 in brain function following cerebral ischemia

Cardiopulmonary arrest (CA) is a major cause of death/disability in the U.S. with poor prognosis and survival rates. Current therapeutic challenges are physiologically complex because they involve hypoperfusion (decreased cerebral blood flow), neuroinflammation, and mitochondrial dysfunction. We previously discovered novel serum/glucocorticoid-regulated kinase 1 (SGK1) is highly expressed in brain of neurons that are susceptible to ischemia (hippocampus and cortex). We inhibited SGK1 and utilized pharmacological (specific inhibitor, GSK650394) and neuron-specific genetic approaches (shRNA) in rodent models of CA to determine if SGK1 is responsible for hypoperfusion, neuroinflammation, mitochondrial dysfunctional, and neurological deficits after CA. Inhibition of SGK1 alleviated cortical hypoperfusion and neuroinflammation (via Iba1, GFAP, and cytokine array). Treatment with GSK650394 enhanced mitochondrial function (via Seahorse respirometry) in the hippocampus 3 and 7 days after CA. Neuronal injury (via MAP2, dMBP, and Golgi staining) in the hippocampus and cortex was observed 7 days after CA but ameliorated with SGK1-shRNA. Moreover, SGK1 mediated neuronal injury by regulating the Ndrg1-SOX10 axis. Finally, animals subjected to CA exhibited learning/memory, motor, and anxiety deficits after CA, whereas SGK1 inhibition via SGK1-shRNA improved neurocognitive function. The present study suggests the fundamental roles of SGK1 in brain circulation and neuronal survival/death in cerebral ischemia-related diseases.

Comprehensive analysis of Eleutherococcus senticosus (Rupr. & Maxim.) Maxim. fruits based on UPLC-MS/MS and GC-MS: A rapid qualitative analysis

Eleutherococcus senticosus (Rupr. & Maxim.) Maxim. fruits (ESF), as a natural edible fruit, has long been popularized. However, few studies have conducted comprehensive chemical analyses of it. This study aimed to assess nonvolatile, volatile, and fatty oil components of ESF and to preliminarily explore the antioxidant activities. The qualitative and quantitative analyses of volatile and fatty oil components of ESF from 15 different regions were performed by the gas chromatography-mass spectrometry (GC-MS). Totally, 37 and 28 compounds were identified from volatile oil and fatty oil, respectively. The ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS/MS) was used to accurately detect 43 compounds of nonvolatile components. The volatile and fatty oil components and nonvolatile components of ESF were used as samples to determine the antioxidant activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) in vitro. The components of ESF had antioxidant activity, and the nonvolatile components had stronger antioxidant activity. The results revealed that the proposed method, which is of great significance for the screening of new active ingredients, is valuable for the identification of pharmaceutical component and further development of food industry.

Phytocompounds of Nigella sativa seeds extract and their neuroprotective potential via EGR1 receptor inhibition: A molecular docking study

Bioactivity of Nigella sativa seed extract has the potential as a neuro-protector, offering its promising utility in the clinical setting for brain injury management. This study aimed to identify the phytocompounds contained in the extract of N. sativa seeds and further screen their respective neuronal anti-inflammatory activities in silico. The extract of N. sativa seeds was prepared through successive maceration using non-polar to polar solvents (n-hexane and ethanol, respectively). The phytocompounds in the ethanolic extract were initially identified through qualitative analysis and further analyzed with gas chromatography-mass spectrometry (GC-MS). The spectral data were compared with the compound library for identification. The identified phytocompounds were then simulated computationally for their binding affinities toward the active pocket of early growth response-1 (EGR1) receptor (PDB: 14r2a). We found that the ethanolic extract of N. sativa seeds were predominantly constituted of hexadecanoic acid, ethyl ester (17.15%); linoleic acid ethyl ester (15.0%); octadecanoic acid (13.26%); and ethyl oleate (10.38%). The binding affinity of the phytocompounds ranged from -7.49 kcal/mol (methyl palmitoleate) to -14.31 kcal/mol (9-hexadecanoic acid, methyl ester), with 12 compounds having binding affinity < -10 kcal/mol. In conclusion, ethanolic extract of N. sativa seeds are rich with fatty acids that have active as anti-inflammatory and may exert neuronal protection by inhibiting EGR1 receptor. Studies using animal models to confirm the activity are warranted.

Methyl Palmitate Modulated NMDA-Induced Cerebral Hyperemia in Hypertensive Rats

N-methyl-D-aspartate (NMDA) receptors were found to be dysfunctional in hypertensive rats. Methyl palmitate (MP) has been shown to diminish the nicotine-induced increase in blood flow in the brainstem. The aim of this study was to determine how MP modulated NMDA-induced increased regional cerebral blood flow (rCBF) in normotensive (WKY), spontaneously hypertensive (SHR), and renovascular hypertensive (RHR) rats. The increase in rCBF after the topical application of experimental drugs was measured using laser Doppler flowmetry. Topical NMDA application induced an MK-801-sensitive increase in rCBF in anesthetized WKY rats, which was inhibited by MP pretreatments. This inhibition was prevented by pretreatment with chelerythrine (a PKC inhibitor). The NMDA-induced increase in rCBF was also inhibited by the PKC activator in a concentration-dependent manner. Neither MP nor MK-801 affected the increase in rCBF induced by the topical application of acetylcholine or sodium nitroprusside. Topical application of MP to the parietal cortex of SHRs, on the other hand, increased basal rCBF slightly but significantly. MP enhanced the NMDA-induced increase in rCBF in SHRs and RHRs. These results suggested that MP had a dual effect on the modulation of rCBF. MP appears to play a significant physiological role in CBF regulation.

Perivascular Adipose Tissue and Vascular Smooth Muscle Tone: Friends or Foes?

Perivascular adipose tissue (PVAT) is a specialized type of adipose tissue that surrounds most mammalian blood vessels. PVAT is a metabolically active, endocrine organ capable of regulating blood vessel tone, endothelium function, vascular smooth muscle cell growth and proliferation, and contributing critically to cardiovascular disease onset and progression. In the context of vascular tone regulation, under physiological conditions, PVAT exerts a potent anticontractile effect by releasing a plethora of vasoactive substances, including NO, H₂S, H₂O₂, prostacyclin, palmitic acid methyl ester, angiotensin 1-7, adiponectin, leptin, and omentin. However, under certain pathophysiological conditions, PVAT exerts pro-contractile effects by decreasing the production of anticontractile and increasing that of pro-contractile factors, including superoxide anion, angiotensin II, catecholamines, prostaglandins, chemerin, resistin, and visfatin. The present review discusses the regulatory effect of PVAT on vascular tone and the factors involved. In this scenario, dissecting the precise role of PVAT is a prerequisite to the development of PVAT-targeted therapies.

Faveleira (Cnidoscolus quercifolius Pohl) seed press cake flour: production, characterization and application for use in cookies

BACKGROUND

Food processing produces large volumes of waste that can be transformed into useful and relevant ingredients. The by-product of oil extraction from faveleira seeds is a potentially low-cost raw material that can be used for obtaining functional foods. This study aimed to analyze the physicochemical properties, chemical composition, and antioxidant activity of faveleira (Cnidoscolus quercifolius Pohl) seed press cake flour (FSPCF). Additionally, the chemical composition, antioxidant activity, and physical, microbiological, and sensory aspects of cookies with 0, 25%, or 50% substitution of refined wheat flour (RWF) with FSPCF (0-FSPCF, 25-FSPCF, and 50-FSPCF cookies, respectively) were evaluated.

RESULTS

FSPCF exhibited good physicochemical properties, high antioxidant activity (0.45 ± 0.00 and 42.83 ± 1.30 g TE g^-1 for the DPPH and ABTS methods, respectively), and high polyphenol content (particularly gallic acid at 21015.85 ± 4981.76 g kg^-1 ) and is also rich in minerals and fiber (359.40 ± 1.10 g kg^-1 ). Replacement of RWF with FSPCF increased the activity of antioxidants and the levels of polyphenols, ash, lipids, proteins, and fibers. The 50-FSPCF cookie possessed the highest linoleic acid content (97.50 ± 8.47 g kg^-1 ). Flour replacement influenced the weight of the cookies without affecting the other physical characteristics. The cookies yielded good sensory acceptance and purchase intentions. Contamination was not detected.

CONCLUSION

Faveleira flour possesses high nutritional and bioactive value and can be used as a functional ingredient in cookies and possibly in other bakery products such as bread, cakes, and pastas. © 2022 Society of Chemical Industry.

Palmitic acid methyl ester induces cardiac hypertrophy through activating the GPR receptor-mediated changes of intracellular calcium concentrations and mitochondrial functions

Myocardial hypertrophy is associated with a significant increase in intracellular Ca²⁺ , which can be induced by long-chain fatty acid. Palmitic acid methyl ester (PAME), a fatty acid ester released from adipose tissue, superior cervical ganglion, and retina, has been found to have anti-inflammation, antifibrosis, and peripheral vasodilation effects. However, the effects of PAME on cardiomyocytes are still unclear. The aim of this study was to determine whether PAME could disrupt the intracellular Ca²⁺ balance, leading to cardiomyocyte hypertrophy. Neonatal rat cardiomyocytes were treated with various concentrations (10-100 μM) of PAME for 1-4 days. Cytosolic Ca²⁺ and mitochondrial Ca²⁺ concentrations were examined using Fura-2 AM and Rhod-2, respectively. After treatment with PAME for 4 days, mitochondrial Ca²⁺ , an indicator of the state of mitochondrial permeability transition pore (MPTP), and cell death were monitored by flow cytometric analysis. ATP levels were detected using the ATP assay kit. Cardiomyocyte hypertrophy was analyzed by measuring the cardiac hypertrophy biomarker and cell area using quantitative real time-polymerase chain reaction, Western Blot analysis and immunofluorescence analysis. Our results show that PAME concentration- and time-dependently increased cytosolic and mitochondria Ca²⁺ through the mitochondrial calcium uniporter. Moreover, treatment with PAME for 4 days caused MPTP opening, thereby reducing ATP production and enhancing reactive oxygen species (ROS) generation, and finally led to cardiomyocyte hypertrophy. These effects caused by PAME treatment were attenuated by the G-protein coupled receptor 40 (GPR40) inhibitor. In conclusion, PAME impaired mitochondrial function, which in turn led to cardiomyocyte hypertrophy through increasing the mitochondrial Ca²⁺ levels mediated by activating the GPR40 signaling pathway.

A review on garcinia kola heckel: traditional uses, phytochemistry, pharmacological activities, and toxicology

PURPOSE

Garcinia kola is a medicinal plant commonly known as bitter kola. It is utilised in ethnomedicine for the treatment of diarrhoea, bronchitis, bacterial infection, cough, hepatitis, gonorrhoea, laryngitis, food poison, liver and gastric diseases.

OBJECTIVE

This study reviewed the phytochemistry, pharmacological activities, and ethnomedicinal potentials of G. kola.

MATERIALS AND METHODS

An extensive review was performed using electronic literature collated from ScienceDirect, Springer, Wiley, and PubMed databases.

RESULTS

Phytochemical analysis revealed the isolation of several chemical compounds including 9-octadecenoic acid, linoleic acid, 14-methylpentadecanoic acid, 1-butanol, hexadecanamide, I-4',II-4',I-5,II-5,I-7,II-7-hexahydroxy-I-3,II-8-biflavanone, lanost-7-en-3-one, kolaflavanone (8E)-4-geranyl-3,5-dihydroxybenzophenone, glutinol, Garcinia biflavonoid (GB-2a-II-4'-OMe), 9,19-cyclolanost-24-en-3-ol, 24-methylene, tirucallol, lupeol, β-amyrin, obtusifoliol and Kolaviron. Diverse pharmacological in-vivo and in vitro investigations revealed that G. kola has anti-inflammatory, antimalarial, hepatoprotective, cardioprotective, anti-asthmatic, neuroprotective, antioxidant, and antidiabetic activities.

CONCLUSION

The present study revealed that G. kola has preventive and therapeutic potentials against various diseases in both in vivo and in vitro studies and therefore can be utilised as a raw material in the pharmaceutical industries for the development of therapeutic products. However, there is a need for clinical trial experiments to validate and provide accurate and substantial information on the required safe dosage and efficacy for the treatment of several diseases.

Protein arginine methyltransferase 8 modulates mitochondrial bioenergetics and neuroinflammation after hypoxic stress

Protein arginine methyltransferases (PRMTs) are a family of enzymes involved in gene regulation and protein/histone modifications. PRMT8 is primarily expressed in the central nervous system, specifically within the cellular membrane and synaptic vesicles. Recently, PRMT8 has been described to play key roles in neuronal signaling such as a regulator of dendritic arborization, synaptic function and maturation, and neuronal differentiation and plasticity. Here, we examined the role of PRMT8 in response to hypoxia-induced stress in brain metabolism. Our results from liquid chromatography mass spectrometry, mitochondrial oxygen consumption rate (OCR), and protein analyses indicate that PRMT8(-/-) knockout mice presented with altered membrane phospholipid composition, decreased mitochondrial stress capacity, and increased neuroinflammatory markers, such as TNF-α and ionized calcium binding adaptor molecule 1 (Iba1, a specific marker for microglia/macrophage activation) after hypoxic stress. Furthermore, adenovirus-based overexpression of PRMT8 reversed the changes in membrane phospholipid composition, mitochondrial stress capacity, and neuroinflammatory markers. Together, our findings establish PRMT8 as an important regulatory component of membrane phospholipid composition, short-term memory function, mitochondrial function, and neuroinflammation in response to hypoxic stress.

Activation of Neuropeptide Y2 Receptor Can Inhibit Global Cerebral Ischemia-Induced Brain Injury

Cardiopulmonary arrest (CA) can greatly impact a patient's life, causing long-term disability and death. Although multi-faceted treatment strategies against CA have improved survival rates, the prognosis of CA remains poor. We previously reported asphyxial cardiac arrest (ACA) can cause excessive activation of the sympathetic nervous system (SNS) in the brain, which contributes to cerebral blood flow (CBF) derangements such as hypoperfusion and, consequently, neurological deficits. Here, we report excessive activation of the SNS can cause enhanced neuropeptide Y levels. In fact, mRNA and protein levels of neuropeptide Y (NPY, a 36-amino acid neuropeptide) in the hippocampus were elevated after ACA-induced SNS activation, resulting in a reduced blood supply to the brain. Post-treatment with peptide YY_3-36 (PYY_3-36), a pre-synaptic NPY2 receptor agonist, after ACA inhibited NPY release and restored brain circulation. Moreover, PYY_3-36 decreased neuroinflammatory cytokines, alleviated mitochondrial dysfunction, and improved neuronal survival and neurological outcomes. Overall, NPY is detrimental during/after ACA, but attenuation of NPY release via PYY_3-36 affords neuroprotection. The consequences of PYY_3-36 inhibit ACA-induced 1) hypoperfusion, 2) neuroinflammation, 3) mitochondrial dysfunction, 4) neuronal cell death, and 5) neurological deficits. The present study provides novel insights to further our understanding of NPY's role in ischemic brain injury.

Palmitic acid methyl ester inhibits cardiac arrest-induced neuroinflammation and mitochondrial dysfunction

We previously discovered that palmitic acid methyl ester (PAME) is a potent vasodilator released from the sympathetic ganglion with vasoactive properties. Post-treatment with PAME can enhance cortical cerebral blood flow and functional learning and memory, while inhibiting neuronal cell death in the CA1 region of the hippocampus under pathological conditions (i.e. cerebral ischemia). Since mechanisms underlying PAME-mediated neuroprotection remain unclear, we investigated the possible neuroprotective mechanisms of PAME after 6 min of asphyxial cardiac arrest (ACA, an animal model of global cerebral ischemia). Our results from capillary-based immunoassay (for the detection of proteins) and cytokine array suggest that PAME (0.02 mg/kg) can decrease neuroinflammatory markers, such as ionized calcium binding adaptor molecule 1 (Iba1, a specific marker for microglia/macrophage activation) and inflammatory cytokines after cardiopulmonary resuscitation. Additionally, the mitochondrial oxygen consumption rate (OCR) and respiratory function in the hippocampal slices were restored following ACA (via Seahorse XF24 Extracellular Flux Analyzer) suggesting that PAME can ameliorate mitochondrial dysfunction. Finally, hippocampal protein arginine methyltransferase 1 (PRMT1) and PRMT8 are enhanced in the presence of PAME to suggest a possible pathway of methylated fatty acids to modulate arginine-based enzymatic methylation. Altogether, our findings suggest that PAME can provide neuroprotection in the presence of ACA to alleviate neuroinflammation and ameliorate mitochondrial dysfunction.

Upregulation of serum and glucocorticoid-regulated kinase 1 exacerbates brain injury and neurological deficits after cardiac arrest

Cardiopulmonary arrest (CA) is the leading cause of death and disability in the United States. CA-induced brain injury is influenced by multifactorial processes, including reduced cerebral blood flow (hypoperfusion) and neuroinflammation, which can lead to neuronal cell death and functional deficits. We have identified serum and glucocorticoid-regulated kinase-1 (SGK1) as a new target in brain ischemia previously described in the heart, liver, and kidneys (i.e., diabetes and hypertension). Our data suggest brain SGK1 mRNA and protein expression (i.e., hippocampus), presented with hypoperfusion (low cerebral blood flow) and neuroinflammation, leading to further studies of the potential role of SGK1 in CA-induced brain injury. We used a 6-min asphyxia cardiac arrest (ACA) rat model to induce global cerebral ischemia. Modulation of SGK1 was implemented via GSK650394, a SGK1-specific inhibitor (1.2 μg/kg icv). Accordingly, treatment with GSK650394 attenuated cortical hypoperfusion and neuroinflammation (via Iba1 expression) after ACA, whereas neuronal survival was enhanced in the CA1 region of the hippocampus. Learning/memory deficits were observed 3 days after ACA but ameliorated with GSK650394. In conclusion, SGK1 is a major contributor to ACA-induced brain injury and neurological deficits, while inhibition of SGK1 with GSK650394 provided neuroprotection against CA-induced hypoperfusion, neuroinflammation, neuronal cell death, and learning/memory deficits. Our studies could lead to a novel, therapeutic target for alleviating brain injury following cerebral ischemia.NEW & NOTEWORTHY Upregulation of SGK1 exacerbates brain injury during cerebral ischemia. Inhibition of SGK1 affords neuroprotection against cardiac arrest-induced hypoperfusion, neuroinflammation, neuronal cell death, and neurological deficits.

Stearic acid methyl ester affords neuroprotection and improves functional outcomes after cardiac arrest

Cardiac arrest causes neuronal damage and functional impairments that can result in learning/memory dysfunction after ischemia. We previously identified a saturated fatty acid (stearic acid methyl ester, SAME) that was released from the superior cervical ganglion (sympathetic ganglion). The function of stearic acid methyl ester is currently unknown. Here, we show that SAME can inhibit the detrimental effects of global cerebral ischemia (i.e. cardiac arrest). Treatment with SAME in the presence of asphyxial cardiac arrest (ACA) revived learning and working memory deficits. Similarly, SAME-treated hippocampal slices after oxygen-glucose deprivation inhibited neuronal cell death. Moreover, SAME afforded neuroprotection against ACA in the CA1 region of the hippocampus, reduced ionized calcium-binding adapter molecule 1 expression and inflammatory cytokines/chemokines, with restoration in mitochondria respiration. Altogether, we describe a unique and uncharted role of saturated fatty acids in the brain that may have important implications against cerebral ischemia.

SC411 treatment can enhance survival in a mouse model of sickle cell disease

Sickle cell disease (SCD) is one of the most common inherited blood disorder among African Americans affecting 70,000-100,000 individuals in the United States. It is characterized by abnormal hemoglobin (HbS) which develops into severe hemolytic anemia and vaso-occlusive crisis. Therefore, patients with SCD suffer from a chronic state of inflammation, which is responsible for multiple organ damage, ischemic attacks, and premature death. Another major hallmark of SCD patients is the abnormally low levels of omega-3 fatty acids, especially docosahexaenoic acid (DHA) in their red blood cell membranes. Treatment with DHA can reduce red blood cell adhesion and enhance cerebral blood flow, thus, our main goal is to investigate the effect of SC411, which is a novel, highly purified DHA ethyl ester formulation with a proprietary delivery platform in SCD. Utilizing a transgenic mouse model of SCD (HbSS-Townes) and recurrent hypoxic challenges (10%O₂, 0.5% CO₂ and balance N₂ for 3 h) to mimic ischemic-like conditions, our data suggest that SC411 can elevate blood DHA and eicosapentaenoic acid (EPA) levels after 8 weeks of treatment. SC411 can also decrease arachidonic acid (AA) and sickling of red blood cells. In addition, SC411-treated SCD mice showed presented with cerebral blood flow, alleviated neuroinflammation, and revived working memory which ultimately enhanced overall survival. In summary, this study suggests that treatment with SC411 improves cellular and functional outcomes in SCD mice. This finding may provide novel therapeutic opportunities in the treatment against ischemic injury elicited by SCD.

Protein Arginine Methyltransferases in Cardiovascular and Neuronal Function

The methylation of arginine residues by protein arginine methyltransferases (PRMTs) is a type of post-translational modification which is important for numerous cellular processes, including mRNA splicing, DNA repair, signal transduction, protein interaction, and transport. PRMTs have been extensively associated with various pathologies, including cancer, inflammation, and immunity response. However, the role of PRMTs has not been well described in vascular and neurological function. Aberrant expression of PRMTs can alter its metabolic products, asymmetric dimethylarginine (ADMA), and symmetric dimethylarginine (SDMA). Increased ADMA levels are recognized as an independent risk factor for cardiovascular disease and mortality. Recent studies have provided considerable advances in the development of small-molecule inhibitors of PRMTs to study their function under normal and pathological states. In this review, we aim to elucidate the particular roles of PRMTs in vascular and neuronal function as a potential target for cardiovascular and neurological diseases.

Palmitic Acid Methyl Ester Induces G2/M Arrest in Human Bone Marrow-Derived Mesenchymal Stem Cells via the p53/p21 Pathway

Bone marrow-derived mesenchymal cells (BM-MSCs) are able to differentiate into adipocytes, which can secrete adipokines to affect BM-MSC proliferation and differentiation. Recent evidences indicated that adipocytes can secrete fatty acid metabolites, such as palmitic acid methyl ester (PAME), which is able to cause vasorelaxation and exerts anti-inflammatory effects. However, effects of PAME on BM-MSC proliferation remain unclear. The aim of this study was to investigate the effect of PAME on human BM-MSC (hBM-MSC) proliferation and its underlying molecular mechanisms. hBM-MSCs were treated with PAME for 48 h and then subjected to various analyses. The results from the present study show that PAME significantly reduced the levels of G₂/M phase regulatory proteins, cyclin-dependent kinase 1 (Cdk1), and cyclin B1 and inhibited proliferation in hBM-MSCs. Moreover, the level of Mdm2 protein decreased, while the levels of p21 and p53 protein increased in the PAME-treated hBM-MSCs. However, PAME treatment did not significantly affect apoptosis/necrosis, ROS generation, and the level of Cdc25C protein. PAME also induced intracellular acidosis and increased intracellular Ca²⁺ levels. Cotreatment with PAME and Na⁺/H⁺ exchanger inhibitors together further reduced the intracellular pH but did not affect the PAME-induced decreases of cell proliferation and increases of the cell population at the G₂/M phase. Cotreatment with PAME and a calcium chelator together inhibited the PAME-increased intracellular Ca²⁺ levels but did not affect the PAME-induced cell proliferation inhibition and G₂/M cell cycle arrest. Moreover, the half-life of p53 protein was prolonged in the PAME-treated hBM-MSCs. Taken together, these results suggest that PAME induced p53 stabilization, which in turn increased the levels of p53/p21 proteins and decreased the levels of Cdk1/cyclin B1 proteins, thereby preventing the activation of Cdk1, and eventually caused cell cycle arrest at the G₂/M phase. The findings from the present study might help get insight into the physiological roles of PAME in regulating hBM-MSC proliferation.