Potential Implications of Angiotensin-converting Enzyme 2 Blockades on Neuroinflammation in SARS-CoV-2 Infection.

BACKGROUND: Angiotensin-converting enzyme 2 (ACE2) has been reported as a portal for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Consequently, scientific strategies to combat coronavirus disease of 2019 (COVID-19) were targeted to arrest SARS-CoV-2 invasion by blocking ACE2. While blocking ACE2 appears a beneficial approach to treat COVID-19, clinical concerns have been raised primarily due to the various intrinsic roles of ACE2 in neurological functions. Selective reports indicate that angiotensin receptor blockers (ARBs) and angiotensin-converting enzyme inhibitors (ACEIs) upregulate ACE2 levels. ACE2 metabolizes angiotensin II and several peptides, including apelin-13, neurotensin, kinetensin, dynorphin, (des-Arg9) bradykinin, and (Lys-des-Arg9)-bradykinin, which may elicit neuroprotective effects. Since ARBs and ACEIs upregulate ACE2, it may be hypothesized that patients with hypertension receiving ARBs and ACEIs may have higher expression of ACE2 and thus be at a greater risk of severe disease from the SARS-CoV-2 infections. However, recent clinical reports indicate the beneficial role of ARBs/ACEIs in reducing COVID-19 severity. Together, this warrants a further study of the effects of ACE2 blockades in hypertensive patients medicated with ARBs/ACEIs, and their consequential impact on neuronal health. However, the associations between their blockade and any neuroinflammation also warrant further research. OBJECTIVE: This review collates mechanistic insights into the dichotomous roles of ACE2 in SARSCoV- 2 invasion and neurometabolic functions and the possible impact of ACE2 blockade on neuroinflammation. CONCLUSION: It has been concluded that ACE2 blockade imposes neuroinflammation.

Distinct Modulation of Wild-Type and Selective Gene Mutated Vitamin D Receptor by Essential Polyunsaturated Fatty Acids.

Vitamin-D deficiency is a global concern. Gene mutations in the vitamin D receptor's (VDR) ligand binding domain (LBD) variously alter the ligand binding affinity, heterodimerization with retinoid X receptor (RXR) and inhibit coactivator interactions. These LBD mutations may result in partial or total hormone unresponsiveness. A plethora of evidence reports that selective long chain polyunsaturated fatty acids (PUFAs), including eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and arachidonic acid (AA) bind to the ligand-binding domain of VDR and lead to transcriptional activation. We, therefore, hypothesize that selective PUFAs would modulate the dynamics and kinetics of VDRs, irrespective of the deficiency of vitamin-D. The spatial arrangements of the selected PUFAs in VDR active site were examined by in-silico docking studies. The docking results revealed that PUFAs have fatty acid structure-specific binding affinity towards VDR. The calculated EPA, DHA & AA binding energies (Cdocker energy) were lesser compared to vitamin-D in wild type of VDR (PDB id: 2ZLC). Of note, the DHA has higher binding interactions to the mutated VDR (PDB id: 3VT7) when compared to the standard Vitamin-D. Molecular dynamic simulation was utilized to confirm the stability of potential compound binding of DHA with mutated VDR complex. These findings suggest the unique roles of PUFAs in VDR activation and may offer alternate strategy to circumvent vitamin-D deficiency.

Caenorhabditis elegans as a possible model to screen anti-Alzheimer's therapeutics.

Alzheimer's disease (AD) is regarded as one of the significant health burdens, as the prevalence is raising worldwide and gradually reaching to epidemic proportions. Consequently, a number of scientific investigations have been initiated to derive therapeutics to combat AD with a concurrent advancement in pharmacological methods and experimental models. Whilst, the available experimental pharmacological approaches both in vivo and in vitro led to the development of AD therapeutics, the precise manner by which experimental models mimic either one or more biomarkers of human pathology of AD is gaining scientific attentions. Caenorhabditis elegans (C. elegans) has been regarded as an emerging model for various reasons, including its high similarities with the biomarkers of human AD. Our review supports the versatile nature of C. elegans and collates that it is a well-suited model to elucidate various molecular mechanisms by which AD therapeutics elicit their pharmacological effects. It is apparent that C. elegans is capable of establishing the pathological processes that links the endoplasmic reticulum and mitochondria dysfunctions in AD, exploring novel molecular cascades of AD pathogenesis and underpinning causal and consequential changes in the associated proteins and genes. In summary, C. elegans is a unique and feasible model for the screening of anti-Alzheimer's therapeutics and has the potential for further scientific exploration.

Cis-9, Trans-11 Conjugated Linoleic Acid Reduces Phosphoenolpyruvate Carboxykinase Expression and Hepatic Glucose Production in HepG2 Cells.

Dysregulated hepatic gluconeogenesis is a hallmark of insulin resistance and type 2 diabetes mellitus (T2DM). Although existing drugs have been proven to improve gluconeogenesis, achieving this objective with functional food is of interest, especially using conjugated linoleic acid (CLA) found in dairy products. Both cis-9, trans-11 (c9,t11) and trans-10, cis-12 (t10,c12) isomers of CLA were tested in human (HepG2) and rat (H4IIE) hepatocytes for their potential effects on gluconeogenesis. The hepatocytes exposed for 24 h with 20 µM of c9,t11-CLA had attenuated the gluconeogenesis in both HepG2 and H4IIE by 62.5% and 80.1%, respectively. In contrast, t10,c12-CLA had no effect. Of note, in HepG2 cells, the exposure of c9,t11-CLA decreased the transcription of gluconeogenic enzymes, cytosolic phosphoenolpyruvate carboxykinase (PCK1) by 87.7%, and glucose-6-phosphatase catalytic subunit (G6PC) by 38.0%, while t10,c12-CLA increased the expression of G6PC, suggesting the isomer-specific effects of CLA on hepatic glucose production. In HepG2, the peroxisome proliferator-activated receptor (PPAR) agonist, rosiglitazone, reduced the glucose production by 72.9%. However, co-administration of c9,t11-CLA and rosiglitazone neither exacerbated nor attenuated the efficacy of rosiglitazone to inhibit glucose production; meanwhile, t10,c12-CLA abrogated the efficacy of rosiglitazone. Paradoxically, PPARγ antagonist GW 9662 also led to 70.2% reduction of glucose production and near undetectable PCK1 expression by abrogating CLA actions. Together, while the precise mechanisms by which CLA isomers modulate hepatic gluconeogenesis directly or via PPAR warrant further investigation, our findings establish that c9,t11-CLA suppresses gluconeogenesis by decreasing PEPCK on hepatocytes.

The Link between Knowledge, Attitudes and Practices in Relation to Atmospheric Haze Pollution in Peninsular Malaysia.

Transboundary haze episodes caused by seasonal forest fires have become a recurrent phenomenon in Southeast Asia, with serious environmental, economic, and public health implications. Here we present a cross-sectional survey conducted among people in Kuala Lumpur and surrounds to assess the links between knowledge, attitudes, and practices in relation to the transboundary haze episodes. Of 305 respondents, 125 were amateur athletes participating in a duathlon event and the remainder were surveyed in an inner-city shopping mall. Across the whole sample, people who possessed more factual information about the haze phenomenon showed significantly higher levels of concern. Duathletes were more knowledgeable than non-duathletes and also more concerned about the negative effects of haze, especially on health. For all people who regularly practice outdoor sports (including people interviewed at the shopping mall), higher levels of knowledge and concerned attitudes translated into a greater likelihood of engaging in protective practices, such as cancelling their outdoor training sessions, while those with greater knowledge were more likely to check the relevant air pollution index on a daily basis. Our results indicate that the provision of accurate and timely information about air quality to residents will translate into beneficial practices, at least among particularly exposed individuals, such as amateur athletes who regularly practice outdoor sports.

The reduced proportion of New splenic T-cells in the zinc-deficient growing rat is not due to increased susceptibility to apoptosis.

Dietary zinc deficiency has been associated with an increased risk of infection. It has been reported that zinc-deficient rats have fewer New T-cells (TCRαß(+)CD90(+)) compared to diet-restricted and control rats, which over time could adversely affect the ability of the organism to fight off infections. We hypothesized that the lower proportion of New T-cells in zinc deficiency is due to an increased susceptibility to apoptosis. Weanling, Sprague Dawley rats were assigned to one of four dietary treatment groups for 3 weeks: zinc-deficient (ZD, <1mg zinc/kg, ad libitum), diet-restricted (DR, 30mg zinc/kg, limited to the amount of feed as consumed by ZD), marginally zinc-deficient (MZD, 10mg zinc/kg, ad libitum) or control (CTL, 30mg zinc/kg, ad libitum). Thymocytes and splenocytes were labeled for flow cytometric determination of cell surface markers and DNA staining (for simultaneous determination of the phenotype of apoptotic cells) and assessed by Western blotting for apoptotic markers. Cells were analyzed immediately, or after incubation for 7h with or without dexamethasone. There was no difference in the proportion of CD90(+) thymocytes; however ZD rats had a higher proportion of Cytotoxic (CD90(+)4(-)8(+)) thymocytes compared to MZD and CTL. ZD had a lower proportion of splenic New T-cells compared to DR, MZD and CTL. There was no effect of diet on the proportion of apoptotic thymocytes or splenocytes, except ZD splenoctyes had a lower Bax/Bcl-xl ratio compared to DR and CTL. We characterized the splenic New T-cells into Helper and Cytotoxic subsets and found that ZD had a higher ratio of Helper to Cytotoxic New T-cells compared to MZD and CTL. These results do not support the hypothesis of increased apoptotic removal of New T-cells in ZD in growing rats. The regulation of CD90 expression should be explored in future studies.

A diet high in α-linolenic acid and monounsaturated fatty acids attenuates hepatic steatosis and alters hepatic phospholipid fatty acid profile in diet-induced obese rats.

This study investigated the efficacy of the plant-based n-3 fatty acid, α-linolenic acid (ALA), a dietary precursor of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), for modulating hepatic steatosis. Rats were fed high fat (55% energy) diets containing high oleic canola oil, canola oil, a canola/flax oil blend (C/F, 3:1), safflower oil, soybean oil, or lard. After 12 weeks, C/F and weight-matched (WM) groups had 20% less liver lipid. Body mass, liver weight, glucose and lipid metabolism, inflammation and molecular markers of fatty acid oxidation, synthesis, desaturation and elongation did not account for this effect. The C/F group had the highest total n-3 and EPA in hepatic phospholipids (PL), as well as one of the highest DHA and lowest arachidonic acid (n-6) concentrations. In conclusion, the C/F diet with the highest content of the plant-based n-3 ALA attenuated hepatic steatosis and altered the hepatic PL fatty acid profile.

Activation of phosphatidylinositol-3 kinase, AMP-activated kinase and Akt substrate-160 kDa by trans-10, cis-12 conjugated linoleic acid mediates skeletal muscle glucose uptake.

Conjugated linoleic acid (CLA), a dietary lipid, has been proposed as an antidiabetic agent. However, studies specifically addressing the molecular dynamics of CLA on skeletal muscle glucose transport and differences between the key isomers are limited. We demonstrate that acute exposure of L6 myotubes to cis-9, trans-11 (c9,t11) and trans-10, cis-12 (t10,c12) CLA isomers mimics insulin action by stimulating glucose uptake and glucose transporter-4 (GLUT4) trafficking. Both c9,t10-CLA and t10,c12-CLA stimulate the phosphorylation of phosphatidylinositol 3-kinase (PI3-kinase) p85 subunit and Akt substrate-160 kDa (AS160), while showing isomer-specific effects on AMP-activated protein kinase (AMPK). CLA isomers showed synergistic effects with the AMPK activator, 5-aminoimidazole-4-carboxamide-1-ß-d-ribonucleoside (AICAR). Blocking PI3-kinase and AMPK prevented the stimulatory effects of t10,c12-CLA on AS160 phosphorylation and glucose uptake, indicating that this isomer acts via a PI3-kinase and AMPK-dependent mechanism, whereas the mechanism of c9,t11-CLA remains unclear. Intriguingly, CLA isomers sensitized insulin-Akt-responsive glucose uptake and prevented high insulin-induced Akt desensitisation. Together, these results establish that CLA exhibits isomer-specific effects on GLUT4 trafficking and the increase in glucose uptake induced by CLA treatment of L6 myotubes occurs via pathways that are distinctive from those utilised by insulin.

Dietary supplementation of trans-11-vaccenic acid reduces adipocyte size but neither aggravates nor attenuates obesity-mediated metabolic abnormalities in fa/fa Zucker rats.

Conjugated linoleic acid (CLA) present in dairy and ruminant fat has beneficial effects on metabolic syndrome characteristics in humans and some rodent models. Production practices to increase the milk content of CLA are also substantially elevating trans-11-vaccenic acid (VA). Questions are being raised whether VA has the same beneficial actions as CLA or has adverse biological effects similar to industrially produced trans-fatty acids. The present study examined the effects of dietary supplementation of either 0 or 1·5 % (w/w) VA for 8 weeks on lipidaemia, glycaemia, blood pressure, hepatic steatosis, adipocyte size and molecular markers of inflammation and insulin signalling in fa/fa Zucker rats. Dietary supplementation of VA did not alter feed intake, weight gain, blood pressure or organ:body weight (BW) ratios, except the epididymal fat:BW ratio which was lower in the VA group compared with the control group. The total liver lipid concentration as an indicator of hepatic steatosis was not different between the groups. Likewise, there were no changes in fasting lipidaemia, glycaemia or oral glucose tolerance. Although there were no physiological differences observed between the groups, animals supplemented with VA had smaller adipocytes (approximately 7 % smaller than the controls). The VA group also had higher adipophilin and IL-10 protein levels in epididymal adipose tissue (1·7- and 1·4-fold higher than the controls, respectively); however, there were no changes observed in critical nodes of insulin signalling. The present study provides evidence that supplementation with VA, a naturally produced trans-fat, has some positive effects on adipose tissue and did not exacerbate obesity-mediated metabolic abnormalities.

Acute exposure of L6 myotubes to cis-9, trans-11 and trans-10, cis-12 conjugated linoleic acid isomers stimulates glucose uptake by modulating Ca2+/calmodulin-dependent protein kinase II.

Conjugated linoleic acid (CLA), a dietary fat, has been considered beneficial in metabolic syndrome. Despite several findings indicating that CLA improves glucose clearance, little information is available regarding the cellular dynamics of CLA on skeletal muscle. We sought to investigate the role of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) in cis-9, trans-11(c9,t11) and trans-10, cis-12 (t10,c12) CLA isomer-mediated glucose transport by L6 myotubes. t10,c12-CLA stimulated both intracellular Ca(2+) release (Ca(i)(2+)) and CaMKII phosphorylation, whereas c9,t11-CLA showed only modest effects on both. Sequestering Ca(i)(2+) with BAPTA/AM abrogated the effect of both CLA isomers on Akt substrate-160 kDa (AS160) phosphorylation and glucose uptake by myotubes. Exposing myotubes to KN-93 or autocamtide 2-related inhibitory peptide to block CaMKII activity prevented both CLA isomers from inducing AS160 phosphorylation and glucose transport. Likewise, genetic knockdown of CaMKII in myotubes using siRNA completely abolished CLA isomer-mediated glucose uptake. These results indicate that CLA isomers require Ca(i)(2+)-CaMKII to mediate glucose uptake. Evidence that CaMKII blockers inhibit t10,c12-CLA-mediated AMP-activated protein kinase (AMPK) activation indicated that CaMKII acts upstream of AMPK in response to t10,c12-CLA. Lastly, CLA isomers stimulated the formation of reactive oxygen species but had no effect on stress-activated protein kinase/c-jun NH(2)-terminal kinase. These data establish that t10,c12-CLA acts via Ca(i)(2+)-CaMKII-AMPK-AS160 to stimulate skeletal muscle glucose transport, whereas the mechanism of c9,t11-CLA remains unclear. Given that impairments in muscle glucose utilisation are apparent in metabolic syndrome, delineating the molecular mechanisms by which CLA isomers mediate muscle glucose uptake may identify new approaches to manage this condition.

Insulinotrophic and insulin-like effects of a high molecular weight aqueous extract of Pterocarpus marsupium Roxb. hardwood.

ETHNOPHARMACOLOGICAL RELEVANCE: Pterocarpus marsupium Roxb. (PM) is an Ayurvedic traditional medicine well known for its antidiabetic potential. AIM: To fractionate the antidiabetic constituent(s) of the aqueous of extract of PM hardwood (PME). MATERIALS AND METHODS: Bio-assay methods including, insulin secretion from mouse pancreas and glucose uptake by mouse skeletal muscle, were used to determine and fractionate the antidiabetic activity of PME. Results obtained from the in vitro experiments were then verified by examining the effect of PME on glucose clearance in normoglycemic, non-diabetic sheep in vivo. RESULTS: Exposure of mouse pancreatic and muscle tissues to PME stimulated the insulin secretion and glucose uptake, respectively, in a concentration-dependent manner. PME-mediated muscle glucose uptake was not potentiated in the presence of insulin indicating that PME acts via pathways which are utilized by insulin. Bio-assay-guided fractionation of PME yielded a high molecular weight fraction which had potent antidiabetic properties in vitro, and in in vivo. CONCLUSIONS: Our findings, we believe for the first time, provide novel insights for the antidiabetic constituents of PM and demonstrate that a high molecular weight constituent(s) of PM has potent insulinotrophic and insulin-like properties.

Domain-dependent modulation of insulin-induced AS160 phosphorylation and glucose uptake by Ca2+/calmodulin-dependent protein kinase II in L6 myotubes.

In skeletal muscle, the molecular mechanisms by which insulin stimulates glucose transport remains incompletely understood. Our study investigated the cellular dynamics of intracellular Ca(2+) mobilisation and Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) activation on insulin-induced skeletal muscle glucose transport. L6 myotubes were treated without or with insulin [100 nM] for 15 min and subsequently monitored for glucose uptake using isotope-labelled 2-deoxyglucose (I-2DOG), intracellular Ca(2+) (Ca(i)(2+)) release using Fluo-4AM and protein phosphorylation using Western blotting. Acute exposure of myotubes to insulin increased both Akt substrate-160 kDa (AS160) phosphorylation and I-2DOG uptake. Insulin concurrently increased Ca(i)(2+) and activated CaMKII. Exposing myotubes to either BAPTA/AM to sequester Ca(i)(2+) or KN-93 to inhibit CaMKII activity, decreased insulin-induced glucose uptake without affecting AS160 phosphorylation. On the other hand, blocking either calmodulin or the autoregulatory domain of CaMKII blocked the effect of insulin on both AS160 phosphorylation and glucose transport. Likewise, genetic knockdown of CaMKII in myotubes using siRNA completely abolished insulin-mediated glucose uptake. These results illustrate impairments in Ca(i)(2+) mobilisation and CaMKII activation are sufficient to negatively influence insulin-dependent glucose transport by L6 myotubes. Additionally, our results show for the first time that Ca(i)(2+) and domain-dependent CaMKII signalling differentially affect insulin-induced AS160 phosphorylation, and establish that Ca(2+) and CaMKII are components of the insulin signalling pathway in L6 myotubes.

Treatment with low-dose resveratrol reverses cardiac impairment in obese prone but not in obese resistant rats.

We hypothesized that a low-dose resveratrol will reverse cardiovascular abnormalities in rats fed a high-fat (HF) diet. Obese prone (OP) and obese resistant (OR) rats were fed an HF diet for 17 weeks; Sprague-Dawley rats fed laboratory chow served as control animals. During the last 5 weeks of study, treatment group received resveratrol daily by oral gavage at a dosage of 2.5 mg/kg body weight. Assessments included echocardiography, blood pressure, adiposity, glycemia, insulinemia, lipidemia, and inflammatory and oxidative stress markers. Body weight and adiposity were significantly higher in OP rats when compared to OR rats. Echocardiographic measurements showed prolonged isovolumic relaxation time in HF-fed OP and OR rats. Treatment with resveratrol significantly improved diastolic function in OP but not in OR rats without affecting adiposity. OP and OR rats had increased blood pressure which remained unchanged with treatment. OP rats had elevated fasting serum glucose and insulin, whereas OR rats had increased serum glucose and normal insulin concentrations. Resveratrol treatment significantly reduced serum glucose while increasing serum insulin in both OP and OR rats. Inflammatory and oxidative stress markers, serum triglycerides and low-density lipoprotein were higher in OP rats, which were significantly reduced with treatment. In conclusion, HF induced cardiac dysfunction in both OP and OR rats. Treatment reversed abnormalities in diastolic heart function associated with HF feeding in OP rats, but not in OR rats. The beneficial effects of resveratrol may be mediated through regression of hyperglycemia, oxidative stress and inflammation.