Cyclic Adenosine Research Articles

PDE4D: A Multipurpose Pharmacological Target.

Phosphodiesterase 4 (PDE4) enzymes catalyze cyclic adenosine monophosphate (cAMP) hydrolysis and are involved in a variety of physiological processes, including brain function, monocyte and macrophage activation, and neutrophil infiltration. Among different PDE4 isoforms, Phosphodiesterases 4D (PDE4Ds) play a fundamental role in cognitive, learning and memory consolidation processes and cancer development. Selective PDE4D inhibitors (PDE4Dis) could represent an innovative and valid therapeutic strategy for the treatment of various neurodegenerative diseases, such as Alzheimer's, Parkinson's, Huntington's, and Lou Gehrig's diseases, but also for stroke, traumatic brain and spinal cord injury, mild cognitive impairment, and all demyelinating diseases such as multiple sclerosis. In addition, small molecules able to block PDE4D isoforms have been recently studied for the treatment of specific cancer types, particularly hepatocellular carcinoma and breast cancer. This review overviews the PDE4DIsso far identified and provides useful information, from a medicinal chemistry point of view, for the development of a novel series of compounds with improved pharmacological properties.

Genetically Encoded Sensors for the In Vivo Detection of Neurochemical Dynamics.

The ability to measure dynamic changes in neurochemicals with high spatiotemporal resolution is essential for understanding the diverse range of functions mediated by the brain. We review recent advances in genetically encoded sensors for detecting neurochemicals and discuss their in vivo applications. For example, notable progress has been made with respect to sensors for second messengers such as cyclic adenosine monophosphate, enabling in vivo real-time monitoring of these messengers at single-cell and even subcellular resolution. Moreover, the emergence of highly sensitive sensors for neurotransmitters and neuromodulators has greatly accelerated the study of these signaling molecules in a wide variety of behavioral models using an array of powerful imaging techniques. Finally, we discuss the future direction of neurochemical sensors, including their ability to measure neurochemical concentrations and the potential for multiplex imaging.

Aniquinazoline B, a Fungal Natural Product, Activates the μ-Opioid Receptor.

The development of new μ-opioid receptor (MOR) agonists without the undesirable side effects, such as addiction or respiratory depression, has been a difficult challenge over the years. In the search for new compounds, we screened our chemical database of over 40.000 substances and further assessed the best 100 through molecular docking. We selected the top 10 compounds and evaluated them for their biological activity and potential to influence cyclic adenosine monophosphate (cAMP) levels. From the tested compounds, compound 7, called aniquinazoline B, belonging to the quinazolinone alkaloids class and isolated from the marine fungus Aspergillus nidulans, showed promising results, by inhibiting cAMP levels and in vitro binding to MOR, verified through microscale thermophoresis. Transcriptomic data investigation profiled the genes affected by compound 7 and discovered activation of different pathways compared to opioids. The western blot analysis revealed compound 7 as a balanced ligand, activating both p-ERK1/2 and β-arrestin1/2 pathways, showing this is a favorable candidate to be further tested.

Computational and in vitro binding studies of theophylline against phosphodiesterases functioning in sperm in presence and absence of pentoxifylline

Fertility is a result of a synergy among the sperm's various functions including capacitation, motility, chemotaxis, acrosome reaction, and, finally, the fertilization of the oocyte. Subpar motility is the most common cause of infertility in males. Cyclic adenosine monophosphate (cAMP) signalling underlies motility and is depleted by the phosphodiesterases (PDEs) in sperm, such as PDE10A, PDE1, and PDE4. Therefore, the PDE inhibitor (PDEI) category of fertility drugs aim to enhance motility in assisted reproduction technologies (ARTs) through inhibition of PDEs, though they might have adverse effects on other physiological variables. For example, the popular drug pentoxifylline (PTX), widely used in ARTs, improves motility but causes premature acrosome reaction and exerts toxicity on the fertilized oocyte. Another xanthine-derived drug, theophylline (TP), has been repurposed for treating infertility, but its mechanism of PDE inhibition remains unexplored. Here, using biophysical and computational approaches, we identified that TP binds to the same binding pocket as PTX with higher affinity than PTX. We also found that PTX and TP co-bind to the same binding pocket, but at different sites.

Efficacy of forskolin as a promising therapy for chronic olfactory dysfunction post COVID-19.

Olfactory dysfunction is increasingly common among COVID-19 patients, impacting their well-being. Reports have demonstrated decreased levels of cyclic adenosine monophosphate and cyclic guanosine monophosphate among patients with chronic olfactory dysfunction. A prospective randomized clinical trial was developed to demonstrate the efficacy of an oral forskolin regimen treatment, an adenylyl cyclase activator that raises intracellular levels of cyclic adenosine monophosphate, for the treatment of olfactory dysfunction following COVID-19, compared to placebo regimen. The study enrolled 285 participants with persistent olfactory dysfunction post COVID-19 infection, randomly assigning them to receive either placebo capsules (n = 120) or oral forskolin capsules (n = 165). Follow-up was conducted to track progress, with 18 participants from the placebo group and 12 from the forskolin group lost during this period. Olfactory function was assessed using the "Sniffin' Sticks" test, measuring threshold, discrimination and identification scores before and after treatment. Subjects administered forskolin capsules demonstrated a significant enhancement in their composite TDI (threshold, discrimination and identification) score, suggesting a notable amelioration in olfactory functionality. Moreover, the discrimination and identification scores notably improved within the forskolin group. Conversely, no significant alterations were observed in the threshold scores. This study suggests that forskolin can contribute potentially to improve chronic olfactory dysfunction post COVID-19. DFM-IRB00012367-23-10-001.

Cannabielsoin (CBE), a CBD Oxidation Product, Is a Biased CB1 Agonist.

Cannabielsoin (CBE) is primarily recognized as an oxidation byproduct of cannabidiol (CBD) and a minor mammalian metabolite of CBD. The pharmacological interactions between CBE and cannabinoid receptors remain largely unexplored, particularly with respect to cannabinoid receptor type 1 (CB1). The present study aimed to elucidate the interaction dynamics of CBE in relation to CB1 by employing cyclic adenosine monophosphate (cAMP) and β-arrestin assays to assess its role as an agonist, antagonist, and positive allosteric modulator (PAM). To our knowledge, this is the first publication to investigate CBE's receptor activity in vitro. Our findings reveal that S-CBE acts as an agonist to CB1 with EC50 = 1.23 µg/mL (3.7 µM) in the cAMP assay. No agonist activity was observed in the β-arrestin assay in concentrations up to 12 µM, suggesting a noteworthy affinity towards G-protein activation and the cAMP signaling pathway. Furthermore, in silico molecular docking simulations were conducted to provide a structural basis for the interaction between CBE and CB1, offering insights into the molecular determinants of its receptor affinity and functional selectivity.

Induced pluripotent stem cells derived renal tubular cells from a patient with pseudohypoparathyroidism and its response to parathyroid hormone stimulation.

Creating induced pluripotent stem cells (iPSCs) from somatic cells of patients with genetic diseases offers a pathway to generate disease-specific iPSCs carrying genetic markers. Differentiating these iPSCs into renal tubular cells can aid in understanding the pathophysiology of rare inherited renal tubular diseases through cellular experiments. Two Japanese patients with Pseudohypoparathyroidism (PHP), a 49-year-old woman and a 71-year-old man, were studied. iPSC-derived tubular cells were established from their peripheral blood mononuclear cells (PBMCs). We examined changes in intracellular and extracellular cyclic adenosine monophosphate (cAMP) levels in these cells in response to parathyroid hormone (PTH) stimulation. Renal tubular cells, differentiated from iPSCs of a healthy control (648A1), showed a PTH-dependent increase in both intracellular and extracellular cAMP levels. However, the renal tubular cells derived from the PHP patients' iPSCs showed inconsistent changes in cAMP levels upon PTH exposure. We successfully created disease-specific iPSCs from PHP patients' PBMCs, differentiated them into tubular cells, and replicated the distinctive response of the disease to PTH in vitro. This approach could enhance our understanding of the pathophysiology of inherited renal tubular diseases and contribute to developing effective treatments.

Ion Signaling in Cell Motility and Development in Dictyostelium discoideum.

Cell-to-cell communication is fundamental to the organization and functionality of multicellular organisms. Intercellular signals orchestrate a variety of cellular responses, including gene expression and protein function changes, and contribute to the integrated functions of individual tissues. Dictyostelium discoideum is a model organism for cell-to-cell interactions mediated by chemical signals and multicellular formation mechanisms. Upon starvation, D. discoideum cells exhibit coordinated cell aggregation via cyclic adenosine 3',5'-monophosphate (cAMP) gradients and chemotaxis, which facilitates the unicellular-to-multicellular transition. During this process, the calcium signaling synchronizes with the cAMP signaling. The resulting multicellular body exhibits organized collective migration and ultimately forms a fruiting body. Various signaling molecules, such as ion signals, regulate the spatiotemporal differentiation patterns within multicellular bodies. Understanding cell-to-cell and ion signaling in Dictyostelium provides insight into general multicellular formation and differentiation processes. Exploring cell-to-cell and ion signaling enhances our understanding of the fundamental biological processes related to cell communication, coordination, and differentiation, with wide-ranging implications for developmental biology, evolutionary biology, biomedical research, and synthetic biology. In this review, I discuss the role of ion signaling in cell motility and development in D. discoideum.

Polygonati rhizoma fermentation by Monascus ruber and evaluation of fermentation products in vitro

This study investigated the conditions for polygonati rhizoma (PR) fermentation by Monascus ruber and the lipid-lowering activity of the resulting product. Monascus ruber was used for the solid-state fermentation of PR, and the response surface method was used to optimize the fermentation culture medium parameters. The optimal fermentation system yielded a maximum monacolin K concentration of 21.82 ± 0.34 mg/g. The fermentation conditions were as follows: 12.5 mmol/kg of L-glutamic acid, 0.64 mmol/kg of cyclic adenosine monophosphate, 3.0 wt% of yeast extract powder, a fermentation period of 15 days, and a fermentation temperature of 30 ℃. The binding capacities of unfermented PR, “Nine-Steam-Nine-Bask” processed Polygonati rhizoma (NPR), and Monascus ruber solid-state fermented polygonati rhizoma (MPR) to sodium cholate, sodium taurocholate, and sodium glycolate were determined. MPR showed a stronger bile acid-binding capacity than unfermented PR. In addition, MPR exhibited the highest cholesterol inhibitory capacity of 51.43±1.41 %. Thus, MPR can be used as a potential antilipemic agent with potent hypolipidemic effects.

Bisphenol S causes excessive estrogen synthesis by activating FSHR and the downstream cAMP/PKA signaling pathway

Estrogen excess in females has been linked to a diverse array of chronic and acute diseases. Emerging research shows that exposure to estrogen-like compounds such as bisphenol S leads to increases in 17β-estradiol levels, but the mechanism of action is unclear. The aim of this study was to reveal the underlying signaling pathway-mediated mechanisms, target site and target molecule of action of bisphenol S causing excessive estrogen synthesis. Human ovarian granulosa cells SVOG were exposed to bisphenol S at environmentally relevant concentrations (1 μg/L, 10 μg/L, and 100 μg/L) for 48 h. The results confirms that bisphenol S accumulates mainly on the cell membrane, binds to follicle stimulating hormone receptor (FSHR) located on the cell membrane, and subsequently activates the downstream cyclic adenosine monophosphate/protein kinase A (cAMP/PKA) signaling pathway, leading to enhanced conversion of testosterone to 17β-estradiol. This study deepens our knowledge of the mechanisms of environmental factors in pathogenesis of hyperestrogenism.

Neuroprotective effect of omidenepag on excitotoxic retinal ganglion cell death regulating COX-2–EP2–cAMP–PKA/Epac pathway via Neuron–Glia interaction

Glutamate excitotoxicity is involved in retinal ganglion cell (RGC) death in various retinal degenerative diseases, including ischemia–reperfusion injury and glaucoma. Excitotoxic RGC death is caused by both direct damage to RGCs and indirect damage through neuroinflammation of retinal glial cells. Omidenepag (OMD), a novel E prostanoid receptor 2 (EP2) agonist, is a recently approved intraocular pressure-lowering drug. The second messenger of EP2 is cyclic adenosine monophosphate (cAMP), which activates protein kinase A (PKA) and exchange protein directly activated by cAMP (Epac). In this study, we investigated the neuroprotective effects of OMD on excitotoxic RGC death by focusing on differences in cAMP downstream signaling from the perspective of glia–neuron interactions.We established a glutamate excitotoxicity model in vitro and NMDA intravitreal injection model in vivo. In vitro, rat primary RGCs were used in an RGC survival rate assay. MG5 cells (mouse microglial cell line) and A1 cells (astrocyte cell line) were used for immunocytochemistry and Western blotting to evaluate the expressions of COX-1/2, PKA, Epac1/2, pCREB, cleaved caspase-3, inflammatory cytokines, and neurotrophic factors. Mouse retinal specimens underwent hematoxylin and eosin staining, flat-mounted retina examination, and immunohistochemistry.OMD significantly suppressed excitotoxic RGC death, cleaved caspase-3 expression, and activated glia both in vitro and in vivo. Moreover, it inhibited Epac1 and inflammatory cytokine expression and promoted COX-2, pCREB, and neurotrophic factor expression.OMD may have neuroprotective effects through inhibition of the Epac pathway and promotion of the COX-2–EP2–cAMP–PKA pathway by modulating glia–neuron interaction.

Anti-thrombotic effects of arteanoflavone by regulating cyclic nucleotides and aggregation on human platelets

Excessive clotting or abnormal platelet accumulation can lead to serious cardiovascular disorders such as atherosclerosis, stroke, and thrombosis. Therefore, it is imperative to identify compounds capable of controlling or impeding platelet aggregation to prevent the onset of cardiovascular diseases. Arteanoflavone, a compound extracted from Artemisia iwayomogi, has not garnered scientific recognition for its potential health benefits, recent studies have substantiated its anti-inflammatory, antioxidant, and anti-allergic properties. However, the precise mechanisms by which arteanoflavone influences platelet aggregation and blood clot formation have not been conclusively established. This research investigates arteanoflavone’s role in these processes, particularly in platelets induced by collagen. The study reveals a significant increase in the production of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) correlating with the administered dosage of arteanoflavone. Concurrently, a noticeable escalation is observed in substrates of cAMP-dependent kinase and cGMP-dependent kinase, specifically VASP and inositol 1,4,5-trisphosphate receptor (IP3R).Arteanoflavone demonstrates its ability to limit Ca2+ movement in the dense tubular system through IP3R phosphorylation. Moreover, phosphorylated VASP inhibits the binding of fibrinogen to αIIb/β3, thus suppressing platelet activity. Arteanoflavone also stimulates the phosphorylation of PI3K/Akt, a protein linked to platelet granule release, and MAPK (ERK, JNK, and p38) protein, associated with both platelet granule release and TXA2 production.Lastly, arteanoflavone impedes collagen-induced platelet aggregation and blood clot formation by inhibiting fibrin production in thrombin-induced platelets. Hence, it is suggested that arteanoflavone could be valuable as an agent that effectively deters platelet inhibition and blood clot formation through antiplatelet mechanisms.

P-802 Exploring the effects of phthalate mixtures on human endometrial organoids: Insights into transcriptomic and proteomic profiles throughout the menstrual cycle

Abstract Study question Does the exposure of human endometrial organoids (hEOs) to phthalates influence their transcriptomic and proteomic profiles, particularly during the window of implantation? Summary answer The mixture of phthalates altered the expression of several genes which are essential during the window of implantation. What is known already hEOs display a robust responsiveness to steroid hormones and accurately reproduce essential morphological features observed in the receptive endometrium in vivo. The conventional approach to evaluating chemical health risks has predominantly been centered on the assessment of individual substances, overlooking the reality that individuals are regularly exposed to diverse mixtures of phthalates, a class of Endocrine Disrupting Chemicals (EDCs). There is a limited number of studies indicating that phthalates and their combinations can have a negative impact on the endometrium. To this purpose, we explore the effect of this mixture on endometrial receptivity during the Window Of Implantation (WOI). Study design, size, duration Endometrial tissues (n = 6) used for this study were obtained, with written informed consent from all participants. The endometrial organoids were generated from the biopsies and treated with hormones to mimic the WOI. Samples were then exposed with a mixture of phthalates in order to study the transcriptomic and proteomic changes on these cells throughout the menstrual cycle, especially the WOI. Participants/materials, setting, methods hEOs were generated from endometrial biopsies of healthy volunteers (n = 6). Organoids were cultured for 4 days and then divided into: untreated without any hormonal treatment; stimulated with 10 nM estrogen (E2); treated with 10 nM estrogen, 1μM progesterone (P4) and 1μM cyclic adenosine monophosphate (cAMP). EOs were further on exposed to the phthalate mixture. Proteomic profiling was performed using 2-D electrophoresis and Mass spectrometry. Samples were also subject to transcriptomic analysis, by RNA sequencing. Main results and the role of chance hEOs present a suitable in vitro model for the screening of the impact of phthalate mixtures on the endometrium throughout the menstrual cycle. Cytotoxicity test confirmed that the chosen concentration (100x of the value referring to the geometrical means in urine) of the mixture is not toxic for the cells. The transcriptomic and proteomic analyses revealed several up-regulated or down-regulated genes which are involved into pivotal pathways implicated to the WOI. Limitations, reasons for caution This study represents a preliminary experiment. All results need to be validated on an enlarged number of samples to provide more statistical strength. Wider implications of the findings hEOs offer a robust in vitro model to simulate and gain a more profound comprehension of the consequences arising from the combinatory effects of EDCs, on the endometrium. This model proves valuable in examining the impact of various EDCs across different phases of the menstrual cycle. Trial registration number not applicable

Preclinical antidiabetic and antioxidant effects of Erythrophleum africanum (benth.) harms in streptozotocin-induced diabetic nephropathy.

This study investigated the antidiabetic effects of the methanolic extract of E.africanum (MEEA) stem bark on streptozotocin (STZ)-induced diabetic nephropathy (DN) in Wistar rats. The invitro enzyme (α-amylase) inhibitory activity of MEEA was measured using a standard procedure. Diabetic rats with fasting blood glucose above 250 mg/dL were considered diabetic and were divided intothe following groups: control (distilled water-treated), diabetic-control, diabetic metformin (100 mg/kg), diabetes + MEEA (150 mg/kg), and diabetes + MEEA (300 mg/kg) via oral gavage once daily for 14days. At the end of the experimental period, kidney tissues were collected for biochemical and histological analyses. Kidney apoptosis and marker gene expression were measured by real-time quantitative PCR. MEEA exhibited α-amylase inhibitory effects. MEEA significantly (p<0.05) reduced the STZ-induced increases in blood glucose, serum urea, serum creatinine, uric acid, alanine aminotransferase, alkaline phosphatase, and malondialdehyde and increased the STZ-induced decreases in superoxide dismutase, catalase, and reduced glutathione. In addition, MEEA protects against DN by significantly downregulating the mRNA expression of cyclic adenosine monophosphate (cAMP), protein kinase A (PKA), cAMP-response binding protein (CREB), and cFOS and upregulating B-cell lymphoma 2 (Bcl-2), suggesting that the nephroprotective ability of MEEA is due to the modulation of the cAMP/PKA/CREB/cFOS signaling pathway. Furthermore, MEEA treatment protected against histopathological alterations observed in diabetic rats. The data from this study suggest that MEEA modulates glucose homeostasis and inhibits redox imbalance in DN rats.

Adenosine signalling to astrocytes coordinates brain metabolism and function

Brain computation performed by billions of nerve cells relies on a sufficient and uninterrupted nutrient and oxygen supply1,2. Astrocytes, the ubiquitous glial neighbours of neurons, govern brain glucose uptake and metabolism3,4, but the exact mechanisms of metabolic coupling between neurons and astrocytes that ensure on-demand support of neuronal energy needs are not fully understood5,6. Here we show, using experimental in vitro and in vivo animal models, that neuronal activity-dependent metabolic activation of astrocytes is mediated by neuromodulator adenosine acting on astrocytic A2B receptors. Stimulation of A2B receptors recruits the canonical cyclic adenosine 3′,5′-monophosphate–protein kinase A signalling pathway, leading to rapid activation of astrocyte glucose metabolism and the release of lactate, which supplements the extracellular pool of readily available energy substrates. Experimental mouse models involving conditional deletion of the gene encoding A2B receptors in astrocytes showed that adenosine-mediated metabolic signalling is essential for maintaining synaptic function, especially under conditions of high energy demand or reduced energy supply. Knockdown of A2B receptor expression in astrocytes led to a major reprogramming of brain energy metabolism, prevented synaptic plasticity in the hippocampus, severely impaired recognition memory and disrupted sleep. These data identify the adenosine A2B receptor as an astrocytic sensor of neuronal activity and show that cAMP signalling in astrocytes tunes brain energy metabolism to support its fundamental functions such as sleep and memory.

P-621 Rekovelle® vs Gonal-F®: in vitro characterization of intracellular signals induced by the two FSH preparations

Abstract Study question Do Rekovelle® and Gonal-F® modulate preparation-specific signalling? Summary answer Gonal-F® and Rekovelle® induce preparation-specific pattern of intracellular signalling. What is known already Rekovelle® and Gonal-F® are two commercial preparations of recombinant FSH used in assisted reproduction. These preparations differ in originator cells (PER.C6® cell line of human fetal retinal origin for Rekovlle®; modified Chinese Hamster Ovary cell line for Gonal-F®), likely reflecting glycosylation profiles impacting their mode of action. Study design, size, duration 3-year in vitro functional comparison of Rekovelle® and Gonal-F®, using the transfected HEK293 cell line expressing FSH receptor (FSHR). Participants/materials, setting, methods FSHR-expressing HEK293 cells were treated with increasing concentrations of GonalF® and Rekovelle® (pM-µM) to evaluate receptor-receptor interaction and trafficking, intracellular cyclic adenosine monophosphate (cAMP) and Ca2+ increase by bioimaging techniques, as well as phospho-protein by Western blotting, and genomic effects by CRE-luciferase reporter gene activity. Main results and the role of chance Both the preparations induced similar, dose-dependent increase of receptor trafficking through intracellular organelles. These data were obtained by evaluation of the interaction between FSHR and endosomal markers RAB-GTPases (Rab) 5 and 7. Rekovelle® induced more pronounced steroifogenic signals than Gonal-F®, detected as FSHR-FSHR interactions at the cell membrane, cAMP accumulation, cAMP-responsive elements binding protein (CREB) phosphorylation and CRE promoter activity. Interestingly, while cell treatment by Gonal-F® mediated complete dose-response of cAMP, consisting in the continuous increase of the second messenger together with the increase of FSH concentration, Rekovelle® had biphasic action where cAMP increased from 0 to 100 nM although decreased at 1 µM Rekovelle® dose. Moreover, Rekovelle® was 10-times more potent than Gonal-F® in activating intracellular Ca2+ activation. The two preparations induced similar pattern of extracellular signal-regulated kinases 1 and 2 (ERK1/2) phosphorylation. In conclusion, Rekovelle® has higher potency than Gonal-F® in activating cAMP- and Ca2+-dependent intracellular events, potentially resulting in preparation-specific steroidogenic pattern. Limitations, reasons for caution Experiments were performed in the transfected HEK293 cell line in vitro and should be confirmed by clinical observations. Wider implications of the findings We described different intracellular events mediated by Gonal-F® and Rekovelle® in vitro, likely originated by different glycan profiles and possibly impacting the ovarian response during assisted reproduction. Trial registration number Not Applicable

Increase in bile acids after sleeve gastrectomy improves metabolism by activating GPBAR1 to increase cAMP in mice with nonalcoholic fatty liver disease.

Bile acids (BAs) concentration can affect metabolic improvement caused by bariatric surgery and BA concentrations increase in patients after sleeve gastrectomy (SG). Here, how BAs after SG affect metabolism in nonalcoholic fatty liver disease (NAFLD) was studied. Mice were given high-fat diet (HFD) to induce NAFLD and received SG surgery. Hepatic and fecal BA concentrations in mice were detected by liquid chromatography-tandem mass spectrometry method. BA-related genes were detected by quantitative real-time polymerase chain reaction. G protein BA receptor 1 (GPBAR1) expression was identified using western blot analysis. NAFLD mice after SG received GPBAR1 inhibitor Triamterene. The weight of mice and mice liver was detected. Mouse liver tissue was observed by hematoxylin-eosin and Oil Red O staining. Triglyceride (TG), nonesterified fatty acid (NEFA), and cyclic adenosine monophosphate (cAMP) levels in mouse liver tissue were analyzed by metabolic assay and enzyme-linked immune sorbent assay. SG boosted increase in hepatic total/conjugated BAs and related genes and GPBAR1 expression, and attenuated increase in fecal total BAs/muricholic acid in HFD-induced mice and increased fecal taurine-BAs in HFD-induced mice. Triamterene (72 mg/kg) reversed the inhibitory role of SG in HFD-induced increase of body weight, lipid accumulation, inflammatory cell infiltration, and increase of hepatic weight and TG/NEFA content, and counteracted the positive role of SG in HFD-induced increase of hepatic cAMP concentration in mice. BAs improve metabolism via activating GPBAR1 to increase cAMP in NAFLD mice after SG.

A novel phosphodiesterase inhibitor for the treatment of chronic liver injury and metabolic diseases.

Chronic liver disease (CLD) leads to approximately two million deaths annually. Cyclic adenosine monophosphate (cAMP) signaling has long been studied in liver injury, particularly in the regulation of fatty acid (FA) β-oxidation and pro-inflammatory polarization of tissue-resident lymphocytes. Phosphodiesterase 4B (PDE4B) inhibition has been explored as a therapeutic modality, but these drugs have had limited success and are known to cause significant adverse effects. The PDE4 inhibitor 2-(4-([2-(5-Chlorothiophen-2-yl)-5-ethyl-6-methylpyrimidin-4-yl]amino)phenyl)acetic acid) (known as A-33) has yet to be explored for the treatment of metabolic diseases. Herein, we evaluated the efficacy of A-33 in the treatment of animal models of alcohol-associated liver disease (ALD) and steatotic liver disease (SLD). We demonstrated that A-33 effectively ameliorated the signs and symptoms of CLD, resulting in significant decreases in serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, decreased overall fat and collagen deposition in the liver, decreased intrahepatic triglyceride (TG) concentrations, and normalized expression of genes related to β-oxidation of fatty acids, inflammation, and extracellular matrix (ECM) deposition. We also designed and synthesized a novel analog of A-33, termed MDL3, which inhibited both PDE4B and PDE5A and was more effective in ameliorating pathophysiological signs and symptoms of liver injury and inflammation. In addition, MDL3 re-sensitized obese mice to glucose and significantly inhibited the pathological remodeling of adipose tissue, which was not observed with A-33 administration. In conclusion, we synthesized and demonstrated that MDL3, a novel PDE4B and PDE5A inhibitor, presents a promising avenue of exploration for treating CLD.

LncRNA CBR3-AS1 is associated with the BCR::ABL1 kinase independent mechanism of tyrosine kinase inhibitor (TKI) resistance in chronic myeloid leukemia patients.

It is difficult for chronic myeloid leukemia (CML) patients with BCR::ABL1 independent drug resistance to achieve optimal efficacy. The aim of this study is to investigate the BCR::ABL1 kinase independent mechanism of tyrosine kinase inhibitor (TKI) resistance in CML patients to develop targeted therapeutic strategy. Herein, we analyzed the long non-coding RNA (lncRNA) and messenger RNA (mRNA) expression profiles of patients who achieved sustained deep molecular response (DMR) after TKI treatment and patients with non-DMR using RNA-seqencing. Furthermore, the differentially expressed lncRNAs and mRNAs were identified. The expression of chosen lncRNA was validated in an expanded cohort, and bioinformatics analysis was performed to analyze the function of selected mRNA. LncRNA data analysis indicated the diversity lncRNA profiles among healthy individuals, CML patients with non-DMR, and CML patients with DMR. Differential expression analysis and Veen plot of up-regulated lncRNAs in patients with non-DMR (compared with healthy individuals) and down-regulated lncRNAs in patients with DMR (compared to patients with non-DMR) revealed that lncRNA CBR3-AS1 overexpression might be related to BCR::ABL1 independent TKI resistance of CML patients. The expression of CBR3-AS1 was then verified in an expanded cohort, suggesting that, compared with control group, there was no statistical difference of CBR3-AS1 expression in DMR group, whereas, CBR3-AS1 was up-regulated in non-DMR group. Moreover, the mRNA data analysis of RNA-sequencing was performed. We considered genes that up-regulated in non-DMR group (compared with control group), down-regulated in DMR group (compared with non-DMR group), showed no statistical difference between control and DMR group as the potential genes that associated with TKI resistance of CML patients. A total of 55 corresponding mRNAs were obtained including KCNA6, a target gene of CBR3-AS1. Further bioinformatics analysis showed that the major interacted genes of KCNA6 were enriched in several resistance-associated pathways including interleukin -17 signaling pathway and cyclic adenosine monophosphate signaling pathway. In conclusion, this work indicates that CBR3-AS1 might be involved in BCR::ABL1 independent TKI resistance of CML patients through targeting KCNA6, providing a novel target for intervention treatment of CML patients with BCR::ABL1 independent TKI resistance.

Phosphodiesterase 4D activity in acrodysostosis-associated neural pathology: too much or too little?

Members of the phosphodiesterase 4 (PDE4) enzyme family regulate the availability of the secondary messenger cyclic adenosine monophosphate (cAMP) and, by doing so, control cellular processes in health and disease. In particular, PDE4D has been associated with Alzheimer's disease and the intellectual disability seen in fragile X syndrome. Furthermore, single point mutations in critical PDE4D regions cause acrodysostosis type 2(ACRDYS2, also referred to as inactivating PTH/PTHrP signalling disorder 5 or iPPSD5), where intellectual disability is seen in ∼90% of patients alongside the skeletal dysmorphologies that are characteristic of acrodysostosis type 1 (ACRDYS1/iPPSD4) and ACRDYS2. Two contrasting mechanisms have been proposed to explain how mutations in PDE4D cause iPPSD5. The first mechanism, the 'over-activation hypothesis', suggests that cAMP/PKA (cyclic adenosine monophosphate/protein kinase A) signalling is reduced by the overactivity of mutant PDE4D, whilst the second, the 'over-compensation hypothesis' suggests that mutations reduce PDE4D activity. That reduction in activity is proposed to cause an increase in cellular cAMP, triggering the overexpression of other PDE isoforms. The resulting over-compensation then reduces cellular cAMP and the levels of cAMP/PKA signalling. However, neither of these proposed mechanisms accounts for the fine control of PDE activation and localization, which are likely to play a role in the development of iPPSD5. This review will draw together our understanding of the role of PDE4D in iPPSD5 and present a novel perspective on possible mechanisms of disease.