Antiplatelet Action of Chloramine Derivatives of Adenosine Phosphates and Their Chemical Activity in Relation to Sulfur-Containing Compounds.

We studied the properties of N6-chloroadenosine phosphates (ATP, ADP, and AMP chloramines) as compounds with potentially increased antiplatelet efficacy determined by their binding to the plasma membrane of platelets. Chloramine derivatives of ATP, ADP, and AMP do not differ in their optical absorption characteristics: their absorption spectra are in the range of 220-340 nm with a maximum at 264 nm. Chloramines of adenosine phosphates are characterized by high reactivity with respect to thiol compounds. In particular, the rate constants of the reaction of N6-chloroadenosine-5'-diphosphate with N-acetylcysteine, reduced glutathione, dithiothreitol, and cysteine reach 59,000, 250,000, 340,000, and 1,250,000 M-1×sec-1, respectively, and only 1.10±0.02 M-1×sec-1 with methionine. It has been found that N6-chloradenosine-5'-triphosphate is a strong inhibitor of platelet functions: it effectively suppresses ADP-induced cell aggregation (IC50 in the whole blood is 5 µM) and inhibits aggregation of preactivated platelets and induces dissociation of their aggregates.

Novel Phenylethanoid Glycosides Improve Hippocampal Synaptic Plasticity via the Cyclic Adenosine Monophosphate-CREB-Brain-Derived Neurotrophic Growth Factor Pathway in APP/PS1 Transgenic Mice.

INTRODUCTION: Alzheimer's disease (AD) is a major public health concern worldwide, but there are still no drugs available that treat it effectively. Previous studies have shown that phenylethanoid glycosides have pharmacological effects, which include anti-AD properties, but the underlying mechanisms by which they ameliorate AD symptoms remain unknown. METHODS: In this study, we used an APP/PS1 AD mouse model to explore the function and mechanisms underlying savatiside A (SA) and torenoside B (TB) in the treatment of AD. SA or TB (100 mg·kg-1·d-1) was orally administered to 7-month-old APP/PS1 mice for 4 weeks. Cognitive and memory functions were measured using behavioral experiments (including the Morris water maze test and the Y-maze spontaneous alternation test). Molecular biology experiments (including Western blotting, immunofluorescence, and enzyme-linked immunosorbent assays) were used to detect any corresponding changes in signaling pathways. RESULTS: The results showed that SA or TB treatment could significantly reduce cognitive impairment in APP/PS1 mice. We also showed that chronic treatment with SA/TB could prevent spine loss, synaptophysin immunoreactivity, and neuronal loss in mice, thereby improving synaptic plasticity and moderating learning and memory deficits. SA/TB administration also promoted the expression of synaptic proteins in APP/PS1 mouse brains and upregulated phosphorylation of proteins in the cyclic adenosine monophosphate (cAMP)/CREB/brain-derived neurotrophic growth factor (BDNF) pathway that are responsible for synaptic plasticity. Additionally, chronic SA/TB treatment increased the levels of BDNF and nerve growth factor (NGF) in the brains of APP/PS1 mice. Both astrocyte and microglia volumes, as well as the generation of amyloid ß, were also decreased in SA/TB-treated APP/PS1 mice compared to control APP/PS1 mice. CONCLUSION: In summary, SA/TB treatment was associated with activation of the cAMP/CREB/BDNF pathway and increased BDNF and NGF expression, indicating that SA/TB improves cognitive functioning via nerve regeneration. SA/TB is a promising candidate drug for the treatment of AD.

Late remdesivir treatment initiation partially protects African green monkeys from lethal Nipah virus infection.

Remdesivir is a nucleotide prodrug with preclinical efficacy against lethal Nipah virus infection in African green monkeys when administered 1 day post inoculation (dpi) (Lo et al., 2019). Here, we determined whether remdesivir treatment was still effective when treatment administration initiation was delayed until 3 dpi. Three groups of six African green monkeys were inoculated with a lethal dose of Nipah virus, genotype Bangladesh. On 3 dpi, one group received a loading dose of 10 mg/kg remdesivir followed by daily dosing with 5 mg/kg for 11 days, one group received 10 mg/kg on 12 consecutive days, and the remaining group received an equivalent volume of vehicle solution. Remdesivir treatment initiation on 3 dpi provided partial protection from severe Nipah virus disease that was dose dependent, with 67% of animals in the high dose group surviving the challenge. However, remdesivir treatment did not prevent clinical disease, and surviving animals showed histologic lesions in the brain. Thus, early administration seems critical for effective remdesivir treatment during Nipah virus infection.

PFKFB2 Inhibits Ferroptosis in Myocardial Ischemia/Reperfusion Injury Through Adenosine Monophosphate-Activated Protein Kinase Activation.

ABSTRACT: Six-phosphofructo-2-kinase/fructose-2, 6-bisphosphatase 2 (PFKFB2) is a key regulator of glycolytic enzyme. This study identified whether PFKFB2 can regulate myocardial ferroptosis in ischemia/reperfusion (I/R) injury. Mice myocardial (I/R) injury and H9c2 cells oxygen-glucose deprivation/reperfusion (OGD/R) models were established. PFKFB2 expression was enhanced in I/R mice and OGD/R H9c2 cells. Overexpression of PFKFB2 improves heart function in I/R mice. Overexpression of PFKFB2 inhibits I/R and OGD/R-induced ferroptosis in mice and H9c2 cells. Mechanistically, overexpression of PFKFB2 activates the adenosine monophosphate-activated protein kinase (AMPK). AMPK inhibitor compound C reverses effect of PFKFB2 overexpression in reducing ferroptosis under OGD/R treatment. In conclusion, PFKFB2 protects hearts against I/R-induced ferroptosis through activation of the AMPK signaling pathway.

Platelet zinc status regulates prostaglandin-induced signaling, altering thrombus formation.

BACKGROUND: Approximately 17.3% of the global population exhibits an element of zinc (Zn2+) deficiency. One symptom of Zn2+ deficiency is increased bleeding through impaired hemostasis. Platelets are crucial to hemostasis and are inhibited by endothelial-derived prostacyclin (prostaglandin I2 [PGI2]), which signals via adenylyl cyclase (AC) and cyclic adenosine monophosphate signaling. In other cell types, Zn2+ modulates cyclic adenosine monophosphate concentrations by changing AC and/or phosphodiesterase activity. OBJECTIVES: To investigate if Zn2+ can modulate platelet PGI2 signaling. METHODS: Platelet aggregation, spreading, and western blotting assays with Zn2+ chelators and cyclic nucleotide elevating agents were performed in washed platelets and platelet-rich plasma conditions. In vitro thrombus formation with various Zn2+ chelators and PGI2 was assessed in whole blood. RESULTS: Incubation of whole blood or washed platelets with Zn2+ chelators caused either embolization of preformed thrombi or reversal of platelet spreading, respectively. To understand this effect, we analyzed resting platelets and identified that incubation with Zn2+ chelators elevated pVASPser157, a marker of PGI2 signaling. In agreement that Zn2+ affects PGI2 signaling, addition of the AC inhibitor SQ22536 blocked Zn2+ chelation-induced platelet spreading reversal, while addition of Zn2+ blocked PGI2-mediated platelet reversal. Moreover, Zn2+ specifically blocked forskolin-mediated AC reversal of platelet spreading. Finally, PGI2 inhibition of platelet aggregation and in vitro thrombus formation was potentiated in the presence of low doses of Zn2+ chelators, increasing its effectiveness in inducing platelet inhibition. CONCLUSION: Zn2+ chelation potentiates platelet PGI2 signaling, elevating PGI2's ability to prevent effective platelet activation, aggregation, and thrombus formation.

Remdesivir.

Remdesivir, marketed under the brand name Veklury, is an antiviral drug with a broad spectrum of activity. There were various countries where the use of Remdesivir for the treatment of COVID-19 was authorized during the pandemic. Remdesivir was first designed to treat hepatitis C, but it was later tested for Ebola virus sickness and Marburg virus infections. Remdesivir is a prodrug designed to facilitate the intracellular transport of GS-441524 monophosphate and its subsequent biotransformation into GS-441524 triphosphate, a ribonucleotide analogue inhibitor of viral RNA polymerase. The objective of this chapter is to provide a comprehensive review of Remdesivir (GS-5734), including its nomenclature, physiochemical properties, preparation methods, identification procedures, numerous qualitative and quantitative analytical techniques, ADME profiles, and pharmacological effects. In addition, the chapter provides a variety of chromatographic and spectroscopic techniques for separating brimonidine from other drugs in combination formulations.

Inhibition of melanogenesis by 3-(1'-methyltetrahydropyridinyl)-2,4-6-trihydroxy acetophenone via suppressing the activity of cAMP response element-binding protein (CREB) and nuclear exclusion of CREB-regulated transcription coactivator 1 (CRTC1).

Exposure to Ultraviolet radiation or α-melanocyte-stimulating hormone (α-MSH) stimulates the Cyclic Adenosine Monophosphate/Protein Kinase A signalling pathway, which leads to the synthesis and deposition of melanin granules in the epidermis. Skin pigmentation is the major physiological defence against inimical effects of sunlight. However, excessive melanin production and accumulation can cause various skin hyperpigmentation disorders. The present study involved the identification of 3-(1'-methyltetrahydropyridinyl)-2,4-6-trihydroxy acetophenone (IIIM-8) as an inhibitor of melanogenesis, IIIM-8 significantly inhibited pigment production both in vitro and in vivo without incurring any cytotoxicity in Human Adult Epidermal Melanocytes (HAEM). IIIM-8 repressed melanin synthesis and secretion both at basal levels and in α-MSH stimulated cultured HAEM cells by decreasing the levels of Cyclic Adenosine Monophosphate (cAMP) and inhibiting the phosphorylation of cAMP response element-binding (CREB) protein, coupled with restoring the phosphorylation of CREB-regulated transcription coactivator 1 (CRTC1) and its nuclear exclusion in HAEM cells. This impeding effect correlates with diminished expression of master melanogenic proteins including microphthalmia-associated transcription factor (MITF), Tyrosinase (TYR), Tyrosinase related protein 1 (TRP1), and Tyrosinase related protein 2 (TRP2). Additionally, topical application of IIIM-8 induced tail depigmentation in C57BL/6J mice. Furthermore, IIIM-8 efficiently mitigated the effect of ultraviolet-B radiation on melanin synthesis in the auricles of C57BL/6J mice. This study demonstrates that IIIM-8 is an active anti-melanogenic agent against ultraviolet radiation-induced melanogenesis and other hyperpigmentation disorders.

High fructose-induced skeletal muscle insulin resistance could be alleviated by berberine via AMPD1 and ADSL.

AMP-activated protein kinase (AMPK) is a master regulator of energy homeostasis that is activated in response to an elevated intracellular AMP/ATP ratio. Although many studies have shown berberine is an AMPK activator widely used in metabolic syndrome, how to properly control AMPK activity remains obscure. Our present study aimed to examine the protective effect of berberine against fructose-induced insulin resistance in rats and L6 cells, as well as its potential activation mechanism on AMPK. The results showed that berberine effectively reversed body weight gain, Lee's index, dyslipidemia and insulin intolerance. Moreover, berberine alleviated inflammatory response, antioxidant capacity and promoted glucose uptake in vivo and in vitro. The beneficial effect was associated with upregulation of both Nrf2 and AKT/GLUT4 pathways, which were regulated by AMPK. Notably, berberine could increase the level of AMP and the ratio of AMP/ATP, then further activate AMPK. Mechanistic experiments revealed that berberine suppressed the expression of adenosine monophosphate deaminase 1 (AMPD1) and promoted the expression of adenylosuccinate synthetase (ADSL). Taken together, berberine exerted excellent therapeutic effect on insulin resistance. And its mode of action may be related to the AMP-AMPK pathway by regulating AMPD1 and ADSL.

Perfluorooctane sulfonate-induced oxidative stress contributes to pancreatic ß-cell apoptosis by inhibiting cyclic adenosine monophosphate pathway: Prevention by pentoxifylline.

Endocrine-disrupting chemical perfluorooctane sulfonate (PFOS) acute exposure stimulates insulin secretion from pancreatic ß-cells. However, chronic exposure to PFOS on pancreatic ß-cells, its role in insulin secretion, and the underlying mechanisms have not been studied. We used rat insulinoma INS-1 and human 1.1b4 islet cells to investigate the chronic effects of PFOS on glucose-stimulated insulin secretion and toxicity implicated in the downregulation of ß-cell functionality. Chronic exposure of INS-1 cells or human pancreatic 1.1b4 ß-cells to PFOS stimulated the small G-protein RAC1-guanosine triphosphate-dependent nicotinamide adenine dinucleotide phosphate oxidase (NOX2/gp91phox) subunit expression and activation. Upregulated NOX2/gp91phox activation led to elevated reactive oxygen species (ROS) production with a decrease in the cyclic adenosine monophosphate/protein kinase A (cAMP/PKA) pathway in both cell types. Inhibition of cAMP/PKA signaling induces ß-cell mitochondrial dysfunction and endoplasmic stress via the loss of PDX1-SERCA2B and glucose-stimulated insulin release. Inhibiting RAC1-NOX2/gp91phox activation or elevating cAMP by pentoxifylline, a Food and Drug Administration-approved phosphodiesterase inhibitor, significantly reduced PFOS-induced ROS production and restored insulin secretory function of pancreatic ß-cells. Enhanced secretory function in pentoxifylline-treated cells was associated with increased stability of PDX1-SERCA2B protein levels. Intriguingly, inhibition of cAMP/PKA signaling impaired pentoxifylline-induced insulin secretion caused by the activation of ROS production and mitochondrial dysfunction. Overall, our findings show that PFOS has a new and first-ever direct chronic effect on pancreatic ß-cell failure through increased RAC1-NOX2/gp91phox activation and pentoxifylline-induced cAMP/PKA signaling, which inhibits PFOS-mediated mitochondrial dysfunction.

Antidepressant-like effect of acute dose of Naringin involves suppression of NR1 and activation of protein kinase A/cyclic adenosine monophosphate response element-binding protein/brain-derived neurotrophic factor signaling in hippocampus.

Naringin (Nr) has been identified to have antidepressant-like effects through repeated treatment. However, the underlying mechanism of the rapid antidepressant-like effects of Nr was still unclear. The present study used behavioral tests, classic depressive model and pharmacological methods to reveal the rapid antidepressant-like potential of Nr. We found that a single dose of Nr (20 mg/kg) produced antidepressant-like action after 2 h in the tail suspension test (TST) and forced swimming test (FST). Moreover, ketamine-like effects were also demonstrated by using the chronic mild stress model (CMS) and learned helplessness (LH), and the results showed that Nr reversed all behavioral defects, TST, FST, source preference test (SPT) in CMS, and LH testing, TST, FST in LH model, at 2 h after a single administration. In addition, Nr (20 mg/kg) could improve the abnormal expressions of NMDA receptor NR1 and PKA/CREB/BDNF pathway in hippocampus 2 h after a single administration in CMS mice. Further investigation revealed that activation of NMDA receptors by NMDA (750 mg/kg) could block the antidepressant effects of acute administration of Nr (20 mg/kg). However, the inhibition of NMDA receptors by MK-801 (0.05 mg/kg) promoted the subdose of Nr (10 mg/kg) to have antidepressant effect, which was similar to the effective dose Nr (20 mg/kg). Taken together, acute dose of Nr produces rapid antidepressant-like action, and the underlying mechanism could be through inhibiting NMDA receptors in the hippocampus.

Novel role of AMPK in cocaine reinforcement via regulating CRTC1.

Repeated cocaine exposure causes compensatory neuroadaptations in neurons in the nucleus accumbens (NAc), a region that mediates reinforcing effects of drugs. Previous studies suggested a role for adenosine monophosphate-activated protein kinase (AMPK), a cellular energy sensor, in modulating neuronal morphology and membrane excitability. However, the potential involvement of AMPK in cocaine use disorder is still unclear. The present study employed a cocaine self-administration model in rats to investigate the effect of AMPK and its target cyclic adenosine monophosphate response element binding protein-regulated transcriptional co-activator 1 (CRTC1) on cocaine reinforcement and the motivation for cocaine. We found that intravenous cocaine self-administration significantly decreased AMPK activity in the NAc shell (NAcsh), which persisted for at least 7 days of withdrawal. Cocaine reinforcement, reflected by self-administration behavior, was significantly prevented or enhanced by augmenting or suppressing AMPK activity pharmacologically and genetically, respectively. No difference in sucrose self-administration behavior was found after the same manipulations. The inhibition of AMPK activity in the NAcsh also increased the motivation for cocaine in progressive-ratio schedules of reinforcement, whereas the activation of AMPK had no effect. The knockdown of CRTC1 in the NAcsh significantly impaired cocaine reinforcement, which was rescued by pharmacologically increasing AMPK activity. Altogether, these results indicate that AMPK in the NAcsh is critical for cocaine reinforcement, possibly via the regulation of CRTC1 signaling. These findings may help reveal potential therapeutic targets and have important implications for the treatment of cocaine use disorder and relapse.

Dual effects of NV-CoV-2 biomimetic polymer: An antiviral regimen against COVID-19.

Remdesivir (RDV) is the only antiviral drug approved for COVID-19 therapy by the FDA. Another drug LAGEVRIO™ (molnupiravir) though has not been approved yet by FDA but has been authorized on December 23, 2021, for emergency use to treat adults with mild-to moderate COVID-19 symptoms and for whom alternative COVID-19 treatment options are not clinically appropriate. The fact is that the efficacy of RDV is, however, limited in vivo though it is highly promising in vitro against SARS-CoV-2 virus. In this paper we are focusing on the action mechanism of RDV and how it can be improved in vivo. The stability of RDV alone and on encapsulation with our platform technology based polymer NV-387 (NV-CoV-2), were compared in presence of plasma in vitro and in vivo. Furthermore, a non-clinical pharmacology study of NV-CoV-2 (Polymer) and NV CoV-2 (Polymer encapsulated Remdesivir) in both NL-63 infected and uninfected rats was done. In addition, the antiviral activity of NV-CoV-2 and NV-CoV-2-R was compared with RDV in a cell culture study. The results are (i) NV-CoV-2 polymer encapsulation protects RDV from plasma-mediated catabolism in both in vitro and in vivo, studies; (ii) Body weight measurements of the normal (uninfected) rats after administration of the test materials (NV-CoV-2 and NV-CoV-2-R) showed no toxic effects. (iii) Body weight measurements and survival rates of the NL-63 infected rats were similar to the uninfected rats after treatment with NV-CoV-2 and NV-CoV-2-R. Overall, the efficacy as an antiviral regimens were found in this order as below; NV-CoV-2-R > NV-CoV-2 > RDV. Our platform technology based NV-387-encapsulated-RDV (NV-CoV-2-R) drug has a dual effect against different variants of the coronaviruses. First, NV-CoV-2 is an antiviral regimen. Secondly, RDV is protected from plasma-mediated degradation in transit. All together, NV-CoV-2-R is the safest and efficient regimen against COVID-19.

Aronia melanocarpa polysaccharide ameliorates liver fibrosis through TGF-ß1-mediated the activation of PI3K/AKT pathway and modulating gut microbiota.

The purpose of this experiment was to investigate the anti-hepatic fibrosis effect of Aronia melanocarpa polysaccharide (AMP) on TAA-induced liver fibrosis mice and its mechanism, as well as the changes in intestinal flora in vivo. This was established with a dose of 200 mg/kg TAA (i.p) once every three days, lasting for eight weeks. Colchicine with 0.4 mg/kg, and AMP (200 and 400 mg/kg) were given by intragastric administration (i.g) after 28 days of intraperitoneal injection of TAA. AMP treatment significantly inhibited the activities of liver injury markers ALT and AST in serum. Histopathological staining demonstrated that AMP significantly reversed TAA-induced hepatocyte necrosis and collagen deposition. In addition, AMP treatment block TGF- ß1/Smads pathway inhibited the production of ECM and alleviates liver fibrosis. Furthermore, AMP treatment enhanced the phosphorylation of PI3K/AKT and decreased the expression of its downstream apoptosis-related proteins in liver, thus effectively alleviating TAA-induced liver fibrosis. In addition, 16S rDNA gene sequencing analysis showed that AMP treatment helped restore the imbalanced ecosystem of gut microbes, increased the proportion of Bacteroidetes and Proteobacteria, and increased species richness. Above findings clearly show that AMP is an effective method for treating liver fibrosis, possibly by improving the gut microbiota.

Synergistic drug combinations designed to fully suppress SARS-CoV-2 in the lung of COVID-19 patients.

Despite new antivirals are being approved against SARS-CoV-2 they suffer from significant constraints and are not indicated for hospitalized patients, who are left with few antiviral options. Repurposed drugs have previously shown controversial clinical results and it remains difficult to understand why certain trials delivered positive results and other trials failed. Our manuscript contributes to explaining the puzzle: this might have been caused by a suboptimal drug exposure and, consequently, an incomplete virus suppression, also because the drugs have mostly been used as add-on monotherapies. As with other viruses (e.g., HIV and HCV) identifying synergistic combinations among such drugs could overcome monotherapy-related limitations. In a cell culture model for SARS-CoV-2 infection the following stringent criteria were adopted to assess drug combinations: 1) identify robust, synergistic antiviral activity with no increase in cytotoxicity, 2) identify the lowest drug concentration inhibiting the virus by 100% (LIC100) and 3) understand whether the LIC100 could be reached in the lung at clinically indicated drug doses. Among several combinations tested, remdesivir with either azithromycin or ivermectin synergistically increased the antiviral activity with no increase in cytotoxicity, improving the therapeutic index and lowering the LIC100 of every one of the drugs to levels that are expected to be achievable and maintained in the lung for a therapeutically relevant period of time. These results are consistent with recent clinical observations showing that intensive care unit admission was significantly delayed by the combination of AZI and RDV, but not by RDV alone, and could have immediate implications for the treatment of hospitalized patients with COVID-19 as the proposed "drug cocktails" should have antiviral activity against present and future SARS-CoV-2 variants without significant overlapping toxicity, while minimizing the onset of drug resistance. Our results also provide a validated methodology to help sort out which combination of drugs are most likely to be efficacious in vivo, based on their in vitro activity, potential synergy and PK profiles.

Effects of the natural antimicrobial peptide aureocin A53 on cells of Staphylococcus aureus and Streptococcus agalactiae involved in bovine mastitis in the excised teat model.

Aureocin A53 is an N-formylated antimicrobial peptide (AMP) produced by Staphylococcus aureus. Aureocin A53 has a broad spectrum of antimicrobial activity against human and animal pathogens. In the present study, its antagonistic activity was investigated towards 30 strains of S. aureus and 30 strains of Streptococcus spp. isolated from bovine mastitis cases in Brazil. Bovine mastitis is a disease that causes a major economic impact worldwide. Aureocin A53 inhibited the growth of all 60 strains tested, including multidrug-resistant streptococcal isolates and strains of S. aureus belonging to different pulsotypes. This AMP proved to be bactericidal against the six target strains randomly selected among staphylococci and streptococci, also exhibiting a lytic mode of action against the staphylococcal cells. Furthermore, it was determined that 2,048 AU/mL of the AMP were required to inhibit 99.99% of the cell growth of the strain less sensitive to aureocin A53. Aureocin A53 was not toxic to bovine mammary gland epithelial cells after a 24-h exposure and maintained its antimicrobial activity when tested in the excised-teat model against strains of S. aureus and Streptococcus agalactiae, the species responsible for most intramammary infections, not only in Brazil but in other countries as well. Therefore, the use of aureocin A53 in the development of new pharmacological products for the prophylaxis and/or treatment of bovine mastitis was considered promising.

Adiponectin Protects Hypoxia/Reoxygenation-Induced Cardiomyocyte Injury by Suppressing Autophagy.

Adiponectin is a cytokine produced by adipocytes and acts as a potential cardioprotective agent and plays an important role in myocardial ischemia/reperfusion injury. In a myocardial hypoxia/reoxygenation model using neonatal rat ventricular myocytes, we investigated the contribution of adiponectin-mediated autophagy to its cardioprotective effects. Cardiomyocytes were exposed to hypoxia/reoxygenation pretreated with or without adiponectin in the presence of absence of rapamycin. Cell viability was analyzed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. Western blotting assay was used to determine the expression levels of microtubule-associated proteins 1A/1B light chain 3B (LC3B), adenosine monophosphate-activated protein kinase (AMPK), mammalian target of rapamycin (mTOR), p62/sequestosome 1, unc-51 like autophagy activating kinase 1 (ULK1), and Beclin-1. Autophagosome formation was detected by monodansylcadaverine staining. We found that hypoxia induced a time dependent decline in cardiomyocyte viability, and increase in autophagy and reoxygenation further augmented hypoxia-induced autophagy induction and consequently reduced cell viability. Adiponectin treatment alleviated hypoxia/reoxygenation-induced cellular damage and autophagy in cardiomyocytes. Adiponectin treatment also attenuated hypoxia/reoxygenation-promoted cardiomyocyte autophagy even in the presence of another autophagy stimulator rapamycin in part by inhibiting vacuolar hydron-adenosine triphosphatase. Additionally, autophagy suppression by adiponectin during hypoxia/reoxygenation was associated with the attenuated phosphorylation of AMPK and ULK1, augmented phosphorylation of mTOR, and the reduced protein expression levels of Beclin-1 in cardiomyocytes. Taken together, these results suggest that adiponectin protects ischemia/reperfusion-induced cardiomyocytes by suppressing autophagy in part through AMPK/mTOR/ULK1/Beclin-1 signaling pathway.

Alterations of Lipid Metabolism in the Heart in Spontaneously Hypertensive Rats Precedes Left Ventricular Hypertrophy and Cardiac Dysfunction.

Disturbances in cardiac lipid metabolism are associated with the development of cardiac hypertrophy and heart failure. Spontaneously hypertensive rats (SHRs), a genetic model of primary hypertension and pathological left ventricular (LV) hypertrophy, have high levels of diacylglycerols in cardiomyocytes early in development. However, the exact effect of lipids and pathways that are involved in their metabolism on the development of cardiac dysfunction in SHRs is unknown. Therefore, we used SHRs and Wistar Kyoto (WKY) rats at 6 and 18 weeks of age to analyze the impact of perturbations of processes that are involved in lipid synthesis and degradation in the development of LV hypertrophy in SHRs with age. Triglyceride levels were higher, whereas free fatty acid (FA) content was lower in the LV in SHRs compared with WKY rats. The expression of de novo FA synthesis proteins was lower in cardiomyocytes in SHRs compared with corresponding WKY controls. The higher expression of genes that are involved in TG synthesis in 6-week-old SHRs may explain the higher TG content in these rats. Adenosine monophosphate-activated protein kinase phosphorylation and peroxisome proliferator-activated receptor α protein content were lower in cardiomyocytes in 18-week-old SHRs, suggesting a lower rate of ß-oxidation. The decreased protein content of α/ß-hydrolase domain-containing 5, adipose triglyceride lipase (ATGL) activator, and increased content of G0/G1 switch protein 2, ATGL inhibitor, indicating a lower rate of lipolysis in the heart in SHRs. In conclusion, the present study showed that the development of LV hypertrophy and myocardial dysfunction in SHRs is associated with triglyceride accumulation, attributable to a lower rate of lipolysis and ß-oxidation in cardiomyocytes.

1'-Cyano Intermediate Enables Rapid and Stereoretentive Access to 1'-Modified Remdesivir Nucleosides.

While biochemical, structural, and computational studies have shown the importance of remdesivir's C1'-substituent in its perturbation of SARS-CoV-2 RdRp action, we recognized the paucity of methods to stereoselectively install substituents at this position as an obstacle to rigorous explorations of SAR and mechanism. We report the utilization of an anomerically pure 1'-cyano intermediate as an entry point to a chemically diverse set of substitutions, allowing for 1'diversification while obviating the need for the tedious separation of anomeric mixtures.

Remdesivir does not affect mitochondrial DNA copy number or deletion mutation frequency in aged male rats: A short report.

Remdesivir is a leading therapy in patients with moderate to severe coronavirus 2 (SARS-CoV-2) infection; the majority of whom are older individuals. Remdesivir is a nucleoside analog that incorporates into nascent viral RNA, inhibiting RNA-directed RNA polymerases, including that of SARS-CoV-2. Less is known about remdesivir's effects on mitochondria, particularly in older adults where mitochondria are known to be dysfunctional. Furthermore, its effect on age-induced mitochondrial mutations and copy number has not been previously studied. We hypothesized that remdesivir adversely affects mtDNA copy number and deletion mutation frequency in aged rodents. To test this hypothesis, 30-month-old male F333BNF1 rats were treated with remdesivir for three months. To determine if remdesivir adversely affects mtDNA, we measured copy number and mtDNA deletion frequency in rat hearts, kidneys, and skeletal muscles using digital PCR. We found no effects from three months of remdesivir treatment on mtDNA copy number or deletion mutation frequency in 33-month-old rats. These data support the notion that remdesivir does not compromise mtDNA quality or quantity at old age in mammals. Future work should focus on examining additional tissues such as brain and liver, and extend testing to human clinical samples.