Novel immunomodulatory properties of adenosine analogs promote their antiviral activity against SARS-CoV-2.

The COVID-19 pandemic reminded us of the urgent need for new antivirals to control emerging infectious diseases and potential future pandemics. Immunotherapy has revolutionized oncology and could complement the use of antivirals, but its application to infectious diseases remains largely unexplored. Nucleoside analogs are a class of agents widely used as antiviral and anti-neoplastic drugs. Their antiviral activity is generally based on interference with viral nucleic acid replication or transcription. Based on our previous work and computer modeling, we hypothesize that antiviral adenosine analogs, like remdesivir, have previously unrecognized immunomodulatory properties which contribute to their therapeutic activity. In the case of remdesivir, we here show that these properties are due to its metabolite, GS-441524, acting as an Adenosine A2A Receptor antagonist. Our findings support a new rationale for the design of next-generation antiviral agents with dual - immunomodulatory and intrinsic - antiviral properties. These compounds could represent game-changing therapies to control emerging viral diseases and future pandemics.

N6-Methyladenosine Guides mRNA Alternative Translation during Integrated Stress Response.

The integrated stress response (ISR) facilitates cellular adaptation to stress conditions via the common target eIF2α. During ISR, the selective translation of stress-related mRNAs often relies on alternative mechanisms, such as leaky scanning or reinitiation, but the underlying mechanism remains incompletely understood. Here we report that, in response to amino acid starvation, the reinitiation of ATF4 is not only governed by the eIF2α signaling pathway, but is also subjected to regulation by mRNA methylation in the form of N6-methyladenosine (m6A). While depleting m6A demethylases represses ATF4 reinitiation, knocking down m6A methyltransferases promotes ATF4 translation. We demonstrate that m6A in the 5' UTR controls ribosome scanning and subsequent start codon selection. Global profiling of initiating ribosomes reveals widespread alternative translation events influenced by dynamic mRNA methylation. Consistently, Fto transgenic mice manifest enhanced ATF4 expression, highlighting the critical role of m6A in translational regulation of ISR at cellular and organismal levels.

Neuronal activity-induced, equilibrative nucleoside transporter-dependent, somatodendritic adenosine release revealed by a GRAB sensor.

The purinergic signaling molecule adenosine (Ado) modulates many physiological and pathological functions in the brain. However, the exact source of extracellular Ado remains controversial. Here, utilizing a newly optimized genetically encoded GPCR-Activation-Based Ado fluorescent sensor (GRABAdo), we discovered that the neuronal activity-induced extracellular Ado elevation is due to direct Ado release from somatodendritic compartments of neurons, rather than from the axonal terminals, in the hippocampus. Pharmacological and genetic manipulations reveal that the Ado release depends on equilibrative nucleoside transporters but not the conventional vesicular release mechanisms. Compared with the fast-vesicular glutamate release, the Ado release is slow (~40 s) and requires calcium influx through L-type calcium channels. Thus, this study reveals an activity-dependent second-to-minute local Ado release from the somatodendritic compartments of neurons, potentially serving modulatory functions as a retrograde signal.

Adenosinergic Modulation of Layer 6 Microcircuitry in the Medial Prefrontal Cortex Is Specific to Presynaptic Cell Type.

Adenosinergic modulation in the PFC is recognized for its involvement in various behavioral aspects including sleep homoeostasis, decision-making, spatial working memory and anxiety. While the principal cells of layer 6 (L6) exhibit a significant morphological diversity, the detailed cell-specific regulatory mechanisms of adenosine in L6 remain unexplored. Here, we quantitatively analyzed the morphological and electrophysiological parameters of L6 neurons in the rat medial prefrontal cortex (mPFC) using whole-cell recordings combined with morphological reconstructions. We were able to identify two different morphological categories of excitatory neurons in the mPFC of both juvenile and young adult rats with both sexes. These categories were characterized by a leading dendrite that was oriented either upright (toward the pial surface) or inverted (toward the white matter). These two excitatory neuron subtypes exhibited different electrophysiological and synaptic properties. Adenosine at a concentration of 30 µM indiscriminately suppressed connections with either an upright or an inverted presynaptic excitatory neuron. However, using lower concentrations of adenosine (10 µM) revealed that synapses originating from L6 upright neurons have a higher sensitivity to adenosine-induced inhibition of synaptic release. Adenosine receptor activation causes a reduction in the probability of presynaptic neurotransmitter release that could be abolished by specifically blocking A1 adenosine receptors (A1ARs) using 8-cyclopentyltheophylline (CPT). Our results demonstrate a differential expression level of A1ARs at presynaptic sites of two functionally and morphologically distinct subpopulations of L6 principal neurons, suggesting the intricate functional role of adenosine in neuronal signaling in the brain.

m6A Facilitates eIF4F-Independent mRNA Translation.

In eukaryotic cells, protein synthesis typically begins with the binding of eIF4F to the 7-methylguanylate (m7G) cap found on the 5' end of the majority of mRNAs. Surprisingly, overall translational output remains robust under eIF4F inhibition. The broad spectrum of eIF4F-resistant translatomes is incompatible with cap-independent translation mediated by internal ribosome entry sites (IRESs). Here, we report that N6-methyladenosine (m6A) facilitates mRNA translation that is resistant to eIF4F inactivation. Depletion of the methyltransferase METTL3 selectively inhibits translation of mRNAs bearing 5' UTR methylation, but not mRNAs with 5' terminal oligopyrimidine (TOP) elements. We identify ABCF1 as a critical mediator of m6A-promoted translation under both stress and physiological conditions. Supporting the role of ABCF1 in m6A-facilitated mRNA translation, ABCF1-sensitive transcripts largely overlap with METTL3-dependent mRNA targets. By illustrating the scope and mechanism of eIF4F-independent mRNA translation, these findings reshape our current perceptions of cellular translational pathways.

WTAP and m6A-modified circRNAs modulation during stress response in acute myeloid leukemia progenitor cells.

N6-methyladenosine (m6A) is one of the most prevalent and conserved RNA modifications. It controls several biological processes, including the biogenesis and function of circular RNAs (circRNAs), which are a class of covalently closed-single stranded RNAs. Several studies have revealed that proteotoxic stress response induction could be a relevant anticancer therapy in Acute Myeloid Leukemia (AML). Furthermore, a strong molecular interaction between the m6A mRNA modification factors and the suppression of the proteotoxic stress response has emerged. Since the proteasome inhibition leading to the imbalance in protein homeostasis is strictly linked to the stress response induction, we investigated the role of Bortezomib (Btz) on m6A regulation and in particular its impact on the modulation of m6A-modified circRNAs expression. Here, we show that treating AML cells with Btz downregulated the expression of the m6A regulator WTAP at translational level, mainly because of increased oxidative stress. Indeed, Btz treatment promoted oxidative stress, with ROS generation and HMOX-1 activation and administration of the reducing agent N-acetylcysteine restored WTAP expression. Additionally, we identified m6A-modified circRNAs modulated by Btz treatment, including circHIPK3, which is implicated in protein folding and oxidative stress regulation. These results highlight the intricate molecular networks involved in oxidative and ER stress induction in AML cells following proteotoxic stress response, laying the groundwork for future therapeutic strategies targeting these pathways.

Recombinant human soluble domain of CD39L3 and ticagrelor: cardioprotective effects in experimental myocardial infarction.

BACKGROUND AND AIMS: The ecto-nucleoside triphosphate diphosphohydrolases of the CD39 family degrade ATP and ADP into AMP, which is converted into adenosine by the extracellular CD73/ecto-5-nucleotidase. This pathway has been explored in antithrombotic treatments but little in myocardial protection. We have investigated whether the administration of solCD39L3 (AZD3366) confers additional cardioprotection to that of ticagrelor alone in a pre-clinical model of myocardial infarction (MI). METHODS: Ticagrelor-treated pigs underwent balloon-induced MI (90 min) and, before reperfusion, received intravenously either vehicle, 1 mg/kg AZD3366 or 3 mg/kg AZD3366. All animals received ticagrelor twice daily for 42 days. A non-treated MI group was run as a control. Serial cardiac magnetic resonance (baseline, Day 3 and Day 42 post-MI), light transmittance aggregometry, bleeding time, and histological and molecular analyses were performed. RESULTS: Ticagrelor reduced oedema formation and infarct size at Day 3 post-MI vs. controls. A 3 mg/kg AZD3366 provided an additional 45% reduction in oedema and infarct size compared with ticagrelor and a 70% reduction vs. controls (P < .05). At Day 42, infarct size declined in all ticagrelor-administered pigs, particularly in 3 mg/kg AZD3366-treated pigs (P < .05). Left ventricular ejection fraction was diminished at Day 3 in placebo pigs and worsened at Day 42, whereas it remained unaltered in ticagrelor ± AZD3366-administered animals. Pigs administered with 3 mg/kg AZD3366 displayed higher left ventricular ejection fraction upon dobutamine stress at Day 3 and minimal dysfunctional segmental contraction at Day 42 (χ2P < .05 vs. all). Cardiac and systemic molecular readouts supported these benefits. Interestingly, AZD3366 abolished ADP-induced light transmittance aggregometry without affecting bleeding time. CONCLUSIONS: Infusion of AZD3366 on top of ticagrelor leads to enhanced cardioprotection compared with ticagrelor alone.

Co-transcriptional R-loops-mediated epigenetic regulation drives growth retardation and docetaxel chemosensitivity enhancement in advanced prostate cancer.

R-loops are prevalent three-stranded nucleic acid structures, comprising a DNA-RNA hybrid and a displaced single-stranded DNA, that frequently form during transcription and may be attributed to genomic stability and gene expression regulation. It was recently discovered that RNA modification contributes to maintain the stability of R-loops such as N6-methyladenosine (m6A). Yet, m6A-modified R-loops in regulating gene transcription remains poorly understood. Here, we demonstrated that insulin-like growth factor 2 mRNA-binding proteins (IGF2BPs) recognize R-loops in an m6A-dependent way. Consequently, IGF2BPs overexpression leads to increased overall R-loop levels, cell migration inhibition, and cell growth retardation in prostate cancer (PCa) via precluding the binding of DNA methyltransferase 1(DNMT1) to semaphorin 3 F (SEMA3F) promoters. Moreover, the K homology (KH) domains of IGF2BPs are required for their recognition of m6A-containing R-loops and are required for tumor suppressor functions. Overexpression of SEMA3F markedly enhanced docetaxel chemosensitivity in prostate cancer via regulating Hippo pathway. Our findings point to a distinct R-loop resolution pathway mediated by IGF2BPs, emphasizing the functional importance of IGF2BPs as epigenetic R-loop readers in transcriptional genetic regulation and cancer biology.The manuscript summarizes the new role of N6-methyladenosine in epigenetic regulation, we introduce the distinct R-loop resolution mediated by IGF2BP proteins in an m6A-dependent way, which probably lead to the growth retardation and docetaxel chemotherapy resistance in prostate cancer. Moreover, our findings first emphasized the functional importance of IGF2BPs as epigenetic R-loop readers in transcriptional genetic regulation and cancer biology. In addition, our research provides a novel RBM15/IGF2BPs/DNMT1 trans-omics regulation m6A axis, indicating the new crosstalk between RNA m6A methylation and DNA methylation in prostate cancer.

Adenosine A2A receptor activation regulates the M1 macrophages activation to initiate innate and adaptive immunity in psoriasis.

Psoriasis is a common inflammatory systemic disease characterized by pro-inflammatory macrophages activation (M1 macrophage) infiltrated in the dermal layer. How M1 macrophage contributes to psoriasis remains unknown. In this study, we found that adenosine A2A receptor (A2AR) agonist CGS 21680 HCl alleviated the imiquimod (IMQ) and mouse IL-23 Protein (rmIL-23)-induced psoriasis inflammation through reducing infiltration of M1. Conversely, Adora2a deletion in mice exacerbated psoriasis-like phenotype. Mechanistically, A2AR activation inhibited M1 macrophage activation via the NF-κB-KRT16 pathway to reduce the secretion of CXCL10/11 and inhibit Th1/17 differentiation. Notably, the KRT16 expression was first found in M1 macrophage in our study, not only in keratinocytes (KCs). CXCL10/11 are first identified as primarily derived from macrophages and dendritic cells (DCs) rather than KCs in psoriasis using single cell RNA sequencing (scRNA-Seq). In total, the study emphasizes the importance of M1 as an innate immune cell in pathogenesis of psoriasis.

Cerebral sympatholysis: experiments on in vivo cerebrovascular regulation and ex vivo cerebral vasomotor control.

Whether cerebral sympathetic-mediated vasomotor control can be modulated by local brain activity remains unknown. This study tested the hypothesis that the application or removal of a cognitive task during a cold pressor test (CPT) would attenuate and restore decreases in cerebrovascular conductance (CVC), respectively. Middle cerebral artery blood velocity (transcranial Doppler) and mean arterial pressure (finger photoplethysmography) were examined in healthy adults (n = 16; 8 females and 8 males) who completed a control CPT, followed by a CPT coupled with a cognitive task administered either 1) 30 s after the onset of the CPT and for the duration of the CPT or 2) at the onset of the CPT and terminated 30 s before the end of the CPT (condition order was counterbalanced). The major finding was that the CPT decreased the index of CVC, and such decreases were abolished when a cognitive task was completed concurrently and restored when the cognitive task was removed. As a secondary experiment, vasomotor interactions between sympathetic transduction pathways (α1-adrenergic and Y1-peptidergic) and compounds implicated in cerebral blood flow control [adenosine, and adenosine triphosphate (ATP)] were explored in isolated porcine cerebral arteries (wire myography). The data reveal α1-receptor agonism potentiated vasorelaxation modestly in response to adenosine, and preexposure to ATP attenuated contractile responses to α1-agonism. Overall, the data suggest a cognitive task attenuates decreases in CVC during sympathoexcitation, possibly related to an interaction between purinergic and α1-adrenergic signaling pathways.NEW & NOTEWORTHY The present study demonstrates that the cerebrovascular conductance index decreases during sympathoexcitation and this response can be positively and negatively modulated by the application or withdrawal of a nonexercise cognitive task. Furthermore, isolated vessel experiments reveal that cerebral α1-adrenergic agonism potentiates adenosine-mediated vasorelaxation and ATP attenuates α1-adrenergic-mediated vasocontraction.

Seizure suppression and neuroprotection in soman-exposed rats following delayed intramuscular treatment of adenosine A1 receptor agonist as an adjunct to standard medical treatment.

Soman produces excitotoxic effects by inhibiting acetylcholinesterase in the cholinergic synapses and neuromuscular junctions, resulting in soman-induced sustained status epilepticus (SSE). Our previous work showed delayed intramuscular (i.m.) treatment with A1 adenosine receptor agonist N-bicyclo-[2.2.1]-hept-2-yl-5'-chloro-5'-deoxyadenosine (ENBA) alone suppressed soman-induced SSE and prevented neuropathology. Using this same rat soman seizure model, we tested if delayed therapy with ENBA (60 mg/kg, i.m.) would terminate seizure, protect neuropathology, and aid in survival when given in conjunction with current standard medical countermeasures (MCMs): atropine sulfate, 2-PAM, and midazolam (MDZ). Either 15- or 30-min following soman-induced SSE onset, male rats received atropine and 2-PAM plus either MDZ or MDZ + ENBA. Electroencephalographic (EEG) activity, physiologic parameters, and motor function were recorded. Either 2- or 14-days following exposure surviving rats were euthanized and perfused for histology. All animals treated with MDZ + ENBA at both time points had 100% EEG seizure termination and reduced total neuropathology compared to animals treated with MDZ (2-day, p = 0.015 for 15-min, p = 0.002 for 30-min; 14-day, p < 0.001 for 15-min, p = 0.006 for 30-min), showing ENBA enhanced MDZ's anticonvulsant and neuroprotectant efficacy. However, combined MDZ + ENBA treatment, when compared to MDZ treatment groups, had a reduction in the 14-day survival rate regardless of treatment time, indicating possible enhancement of MDZ's neuronal inhibitory effects by ENBA. Based on our findings, ENBA shows promise as an anticonvulsant and neuroprotectant in a combined treatment regimen following soman exposure; when given as an adjunct to standard MCMs, the dose of ENBA needs to be adjusted.

Glia-derived adenosine in the ventral hippocampus drives pain-related anxiodepression in a mouse model resembling trigeminal neuralgia.

Glial activation and dysregulation of adenosine triphosphate (ATP)/adenosine are involved in the neuropathology of several neuropsychiatric illnesses. The ventral hippocampus (vHPC) has attracted considerable attention in relation to its role in emotional regulation. However, it is not yet clear how vHPC glia and their derived adenosine regulate the anxiodepressive-like consequences of chronic pain. Here, we report that chronic cheek pain elevates vHPC extracellular ATP/adenosine in a mouse model resembling trigeminal neuralgia (rTN), which mediates pain-related anxiodepression, through a mechanism that involves synergistic effects of astrocytes and microglia. We found that rTN resulted in robust activation of astrocytes and microglia in the CA1 area of the vHPC (vCA1). Genetic or pharmacological inhibition of astrocytes and connexin 43, a hemichannel mainly distributed in astrocytes, completely attenuated rTN-induced extracellular ATP/adenosine elevation and anxiodepressive-like behaviors. Moreover, inhibiting microglia and CD39, an enzyme primarily expressed in microglia that degrades ATP into adenosine, significantly suppressed the increase in extracellular adenosine and anxiodepressive-like behaviors. Blockade of the adenosine A2A receptor (A2AR) alleviated rTN-induced anxiodepressive-like behaviors. Furthermore, interleukin (IL)-17A, a pro-inflammatory cytokine probably released by activated microglia, markedly increased intracellular calcium in vCA1 astrocytes and triggered ATP/adenosine release. The astrocytic metabolic inhibitor fluorocitrate and the CD39 inhibitor ARL 67156, attenuated IL-17A-induced increases in extracellular ATP and adenosine, respectively. In addition, astrocytes, microglia, CD39, and A2AR inhibitors all reversed rTN-induced hyperexcitability of pyramidal neurons in the vCA1. Taken together, these findings suggest that activation of astrocytes and microglia in the vCA1 increases extracellular adenosine, which leads to pain-related anxiodepression via A2AR activation. Approaches targeting astrocytes, microglia, and adenosine signaling may serve as novel therapies for pain-related anxiety and depression.

m 6 A reader IGF2BP1 reduces the sensitivity of nasopharyngeal carcinoma cells to Taxol by upregulation of AKT2.

Taxol is widely used in the treatment of nasopharyngeal carcinoma (NPC); nevertheless, the acquired resistance of NPC to Taxol remains one of the major obstacles in clinical treatment. In this study, we aimed to investigate the role and mechanism of insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) in Taxol resistance of NPC. Taxol-resistant NPC cell lines were established by exposing to gradually increased concentration of Taxol. Relative mRNA and protein levels were tested using qRT-PCR and western blot, respectively. NPC cell viability and apoptosis were assessed by cell counting kit-8 and flow cytometry analysis, respectively. Cell migration and invasion capacities were measured using transwell assay. Interaction between IGF2BP1 and AKT2 was examined by RNA immunoprecipitation assay. The N6-methyladenosine level of AKT2 was tested using methylated RNA immunoprecipitation-qPCR. IGF2BP1 expression was enhanced in Taxol-resistant NPC cell lines. Knockdown of IGF2BP1 strikingly enhanced the sensitivity of NPC cells to Taxol and repressed the migration and invasion of NPC cells. Mechanistically, IGF2BP1 elevated the expression of AKT2 by increasing its mRNA stability. Furthermore, overexpression of AKT2 reversed the inhibitory roles of IGF2BP1 silence on Taxol resistance and metastasis. Our results indicated that IGF2BP1 knockdown enhanced the sensitivity of NPC cells to Taxol by decreasing the expression of AKT2, implying that IGF2BP1 might be promising candidate target for NPC treatment.

CircUGGT2 downregulation by METTL14-dependent m6A modification suppresses gastric cancer progression and cisplatin resistance through interaction with miR-186-3p/MAP3K9 axis.

Chemoresistance is a major therapeutic challenge in advanced gastric cancer (GC). N6-methyladenosine (m6A) RNA modification has been shown to play fundamental roles in cancer progression. However, the underlying mechanisms by which m6A modification of circRNAs contributes to GC and chemoresistance remain unknown. We found that hsa_circ_0030632 (circUGGT2) was a predominant m6A target of METTL14, and METTL14 knockdown (KD) reduced circUGGT2 m6A levels but increased its mRNA levels. The expression of circUGGT2 was markedly increased in cisplatin (DDP)-resistant GC cells. CircUGGT2 KD impaired cell growth, metastasis and DDP-resistance in vitro and in vivo, but circUGGT2 overexpression prompted these effects. Furthermore, circUGGT2 was validated to sponge miR-186-3p and upregulate MAP3K9 and could abolish METTL14-caused miR-186-3p upregulation and MAP3K9 downregulation in GC cells. circUGGT2 negatively correlated with miR-186-3p expression and harbored a poor prognosis in patients with GC. Our findings unveil that METTL14-dependent m6A modification of circUGGT2 inhibits GC progression and DDP resistance by regulating miR-186-3p/MAP3K9 axis.

Coffee, adenosine, and the liver.

A variety of observational studies have demonstrated that coffee, likely acting through caffeine, improves health outcomes in patients with chronic liver disease. The primary pharmacologic role of caffeine is to act as an inhibitor of adenosine receptors. Because key liver cells express adenosine receptors linked to liver injury, regeneration, and fibrosis, it is plausible that the biological effects of coffee are explained by effects of caffeine on adenosinergic signaling in the liver. This review is designed to help the reader make sense of that hypothesis, highlighting key observations in the literature that support or dispute it.

N6 methyladenosine eraser FTO suppresses Staphylococcus aureus-induced ferroptosis of bone marrow mesenchymal stem cells to ameliorate osteomyelitis through regulating the MDM2/TLR4/SLC7A11 signaling pathway.

Osteomyelitis is a bone destructive inflammatory disease caused by infection. Ferroptosis is closely related to multiple inflammatory diseases, but the role of ferroptosis in Staphylococcus aureus (SA)-induced osteomyelitis remains unknown. In the present study, we found that SA treatment promoted the accumulation of iron, Fe2+ , lipid peroxide, and malondialdehyde, increased TFRC and reduced FTH1 and GPX4 to trigger ferroptosis in rat bone marrow mesenchymal stem cells (BMSCs). Interestingly, increased level of N6 methyl adenosine (m6A) modification along with decreased expression level of m6A eraser FTO were observed in SA-induced BMSCs, while upregulating FTO alleviated SA-triggered ferroptosis and protected cell viability in BMSCs. Mechanistically, MDM2 was identified as a target of FTO-mediated m6A demethylation, and FTO upregulation promoted MDM2 instability to downregulated TLR4 signal and elevate the expression of SLC7A11 and GPX4 in SA-induced BMSCs. Functional recovery experiments verified that overexpressing MDM2 or TLR4 reversed the inhibiting effect of FTO upregulation on ferroptosis in SA-treated BMSCs. Additionally, FTO upregulation restrained ferroptosis and pathological damage to bone tissue in SA-induced osteomyelitis model rats. Altogether, m6A eraser FTO alleviates SA-induced ferroptosis in osteomyelitis models partly through inhibiting the MDM2-TLR4 axis.

Cytotoxic effects of kinetin riboside and its selected analogues on cancer cell lines.

N6-[(Furan-2-yl)methyl]adenosine (kinetin riboside) and its seven synthesized analogues were examined for the ability to inhibit the growth of five human carcinoma cell lines and for comparison of normal human lung fibroblast cell line (MRC-5). Out of the compounds evaluated, 8-azakinetin riboside was shown to exhibit significant cytotoxic activity for 72 h treatment against ovarian OVCAR-3 and pancreatic MIA PaCa-2 cancer cells (IC50 = 1.1 µM) with an observed weaker effect against MRC-5 cells (IC50 = 4.6 µM). Kinetin riboside, as well as its N6-[(furan-3-yl)methyl]- and N6-[(thien-2-yl)methyl]- counterparts, also exhibited cytotoxic activities at low micromolar levels but were non-selective over MRC-5 cells.

Design and synthesis of a library of C2-substituted sulfamidoadenosines to probe bacterial permeability.

Antibiotic resistance is a major threat to public health, and Gram-negative bacteria pose a particular challenge due to their combination of a low permeability cell envelope and efflux pumps. Our limited understanding of the chemical rules for overcoming these barriers represents a major obstacle in antibacterial drug discovery. Several recent efforts to address this problem have involved screening compound libraries for accumulation in bacteria in order to understand the structural properties required for Gram-negative permeability. Toward this end, we used cheminformatic analysis to design a library of sulfamidoadenosines (AMSN) having diverse substituents at the adenine C2 position. An efficient synthetic route was developed with installation of a uniform cross-coupling reagent set using Sonogashira and Suzuki reactions of a C2-iodide. The potential utility of these compounds was demonstrated by pilot analysis of selected analogues for accumulation in Escherichia coli.

Enhancing spinal cord stimulation-induced pain inhibition by augmenting endogenous adenosine signalling after nerve injury in rats.

BACKGROUND: The mechanisms for spinal cord stimulation (SCS) to alleviate chronic pain are only partially known. We aimed to elucidate the roles of adenosine A1 and A3 receptors (A1R, A3R) in the inhibition of spinal nociceptive transmission by SCS, and further explored whether 2'-deoxycoformycin (dCF), an inhibitor of adenosine deaminase, can potentiate SCS-induced analgesia. METHODS: We used RNAscope and immunoblotting to examine the distributions of adora1 and adora3 expression, and levels of A1R and A3R proteins in the spinal cord of rats after tibial-spared nerve injury (SNI-t). Electrophysiology recording was conducted to examine how adenosine receptor antagonists, virus-mediated adora3 knockdown, and dCF affect SCS-induced inhibition of C-fibre-evoked spinal local field potential (C-LFP). RESULTS: Adora1 was predominantly expressed in neurones, whereas adora3 is highly expressed in microglial cells in the rat spinal cord. Spinal application of antagonists (100 µl) of A1R (8-cyclopentyl-1,3-dipropylxanthine [DPCPX], 50 µM) and A3R (MRS1523, 200 nM) augmented C-LFP in SNI-t rats (DPCPX: 1.39 [0.18] vs vehicle: 0.98 [0.05], P=0.046; MRS1523: 1.21 [0.07] vs vehicle: 0.91 [0.03], P=0.002). Both drugs also blocked inhibition of C-LFP by SCS. Conversely, dCF (0.1 mM) enhanced SCS-induced C-LFP inhibition (dCF: 0.60 [0.04] vs vehicle: 0.85 [0.02], P<0.001). In the behaviour study, dCF (100 nmol 15 µl-1, intrathecal) also enhanced inhibition of mechanical hypersensitivity by SCS in SNI-t rats. CONCLUSIONS: Spinal A1R and A3R signalling can exert tonic suppression and also contribute to SCS-induced inhibition of spinal nociceptive transmission after nerve injury. Inhibition of adenosine deaminase may represent a novel adjuvant pharmacotherapy to enhance SCS-induced analgesia.

Multi-Omics Integrated Analysis of the Protective Effect of EZH2 Inhibition in Mice with Renal Ischemia-Reperfusion Injury.

INTRODUCTION: Acute kidney injury (AKI) is a common clinical syndrome associated with high morbidity and mortality. Inhibition of the methyltransferase enhancer of zeste homolog 2 (EZH2) by its inhibitor 3-deazaneplanocin A (3-DZNeP) exerts renal benefits in acute renal ischemia-reperfusion injury (IRI). However, the underlying mechanisms are not completely known. This study aimed to elucidate the pathological mechanism of EZH2 in renal IRI by combination of multi-omics analysis and expression profiling in a public clinical cohort. METHODS: In this study, C57BL/6 J mice were used to establish the AKI model, which were treated with 3-DZNeP for 24 h. Kidney samples were collected for RNA-seq analysis, which was combined with publicly available EZH2 chromatin immunoprecipitation sequencing (ChIP-seq) data of mouse embryonic stem cell for a joint analysis to identify differentially expressed genes. Several selected differentially expressed genes were verified by quantitative PCR. Finally, single-nucleus sequencing data and expression profiling in public clinical datasets were used to confirm the negative correlation of the selected genes with EZH2 expression. RESULTS: 3-DZNeP treatment significantly improved renal pathology and function in IRI mice. Through RNA-seq analysis combined with EZH2 ChIP-seq database, 162 differentially expressed genes were found, which might be involved in EZH2-mediated pathology in IRI kidneys. Four differential expressed genes (Scd1, Cidea, Ghr, and Kl) related to lipid metabolism or cell growth were selected based on Gene Ontology and Kyoto Encyclopedia of Genes and Genome enrichment analysis, which were validated by quantitative PCR. Data from single-nucleus RNA sequencing revealed the negative correlation of these four genes with Ezh2 expression in different subpopulations of proximal tubular cells in IRI mice in a different pattern. Finally, the negative correlation of these four genes with EZH2 expression was confirmed in patients with AKI in two clinical datasets. CONCLUSIONS: Our study indicates that Scd1, Cidea, Ghr, and Kl are downstream genes regulated by EZH2 in AKI. Upregulation of EZH2 in AKI inhibits the expression of these four genes in a different population of proximal tubular cells to minimize normal physiological function and promote acute or chronic cell injuries following AKI.