Phosphodiesterase 3A Research Articles

Mapping the glial transcriptome in Huntington’s disease using snRNAseq: selective disruption of glial signatures across brain regions

Huntington’s disease (HD) is an autosomal dominant neurodegenerative disease with a fatal outcome. There is accumulating evidence of a prominent role of glia in the pathology of HD, and we investigated this by conducting single nuclear RNA sequencing (snRNAseq) of human post mortem brain in four differentially affected regions; caudate nucleus, frontal cortex, hippocampus and cerebellum. Across 127,205 nuclei from donors with HD and age/sex matched controls, we found heterogeneity of glia which is altered in HD. We describe prominent changes in the abundance of certain subtypes of astrocytes, microglia, oligodendrocyte precursor cells and oligodendrocytes between HD and control samples, and these differences are widespread across brain regions. Furthermore, we highlight possible mechanisms that characterise the glial contribution to HD pathology including depletion of myelinating oligodendrocytes, an oligodendrocyte-specific upregulation of the calmodulin-dependent 3’,5’-cyclic nucleotide phosphodiesterase 1 A (PDE1A) and an upregulation of molecular chaperones as a cross-glial signature and a potential adaptive response to the accumulation of mutant huntingtin (mHTT). Our results support the hypothesis that glia have an important role in the pathology of HD, and show that all types of glia are affected in the disease.

Anagrelide and idarubicin combination induces GSDME-mediated pyroptosis as a potential therapy for high-PDE3A acute myeloid leukemia.

Acute myeloid leukemia (AML) is an invasive hematopoietic malignancy requiring novel treatment strategies. In this study, we identified phosphodiesterase 3 A (PDE3A) as a potential new target for drug repositioning in AML. PDE3A was preferentially overexpressed in AML cells than in normal cells, and high expression of PDE3A was correlated with lower event-free survival (EFS) in de novo AML patients. The PDE3A inhibitor anagrelide (ANA) profoundly suppresses the proliferation of high PDE3A-expressing AML cells while exhibiting minimal impact on those with low PDE3A expression. Moreover, synergistic effect of ANA with other chemotherapeutic drugs in high PDE3A expression AML cells was observed. The ANA-idarubicin (IDA) combination showed the most remarkable synergistic effect among all ANA-chemotherapeutic drugs commonly used in AML cell line models. Mechanistically, the synergy between ANA and IDA inhibited the survival of PDE3Ahigh AML cell lines through pyroptosis. This mechanism was initiated by GSDME cleavage triggered by caspase-3 activation. In vivo combination treatment of leukemic animals with high PDE3A expression significantly reduced leukemia burden and prolonged survival time compared with single-drug and vehicle control treatments. Our findings suggest that combined ANA and IDA treatment is an innovative and promising therapeutic strategy for AML patients with high PDE3A expression.

Personal Genetic-Hypertension Odyssey From Phenotypes to Genotypes and Targets.

Hypertension requires increased systemic vascular resistance. Thus far, Mendelian hypertension-related genes are related to salt retention, an indirect regulatory effect. With the identification of mutated, overactive, PDE3A (phosphodiesterase 3A), we have uncovered a more direct vasoconstrictive mechanism. The autosomal-dominant syndrome features another specific phenotype, brachydactyly type E. Hypertension and the bony phenotype invariably occur together. We distinguished between these phenotypes by examining individual pedigrees. We implicated the gene encoding the parathyroid hormone-related peptide in the brachydactyly. We identified the hypertensive mechanisms as involving regulatory-region, gain-of-function, exon 4 rare pathogenic variants, in the cAMP-cGMP-catabolizing enzyme, PDE3A. We generated rodent models that recapitulate all human phenotypes. Comparisons not only allowed pathogenic insights into the human condition but also provided intervention models. Moreover, we identified rare pathogenic variants in exon 13 encoding the enzymatic pocket. These patients had identical phenotypes, also corroborated in a rodent model, which produced the same human phenotypes. These data could allow the differentiation between a target organ and blood pressure phenotype. The research allows visualization of enzymatic processes at the intracellular nanodomain level. The scope of this project has elucidated genetic mechanisms important to cartilage development, possibly cancer metastases, and findings relevant to cardiovascular regulation via systemic vascular resistance. For our team, the project was an educational/scientific adventure over a professional lifetime.

Secondary metabolites from the endophytic fungus Letendraea helminthicola A820 with Anti-inflammatory activity.

Two undescribed letendrones A-B (1-2), along with three known compounds, ZL-6 (3), dankasterone B (4) and minimoidione B (5) were isolated from the Aquilaria-derived fungus Letendraea helminthicola A820. The structures of 1 and 2 were established by analysis of spectroscopes including 1D/2D NMR, IR, UV, and HRESIMS. Among them, the configuration of 1 was further confirmed by single-crystal X-ray diffraction. Letendrones A and B were the new phenalenyl derivatives with radical form that were firstly found in nature. In addition, bioactivity of these compounds was evaluated and compounds 3-5 exhibited inhibitory activity against LPS-induced NO production in macrophages with IC50 values of 4.64, 13.90, and 34.07 μM. Furthermore, potential targets of the new compounds were analyzed by molecular docking in silico. As a result, compound 1 showed high binding with predicted 5-HT2c receptor (∆G=-8.2 kcal/mol) potentially associated with depression disease, and compound 2 showed significant connection with phosphodiesterase 3A (∆G=-9.4 kcal/mol) probably against cardiovascular disorders. Our findings firstly reported the high symmetry phenalenyl compounds from natural products which would provide a basis for further development and utilization of the secondary metabolites from the endophytic fungus Letendraea helminthicola A820.

Development of Nitric Oxide-Donating Netarsudil Derivatives as a Synergistic Therapy for Glaucoma with Reduced Ocular Irritation.

Based on the synergistic therapeutic effect of nitric oxide (NO) and Rho-associated protein kinase (ROCK) inhibitors on glaucoma, a series of NO-donating Netarsudil derivatives were designed, synthesized, and their activities in vitro and in vivo were evaluated. Among them, (S)-10e released an appropriate amount of NO in aqueous humor in vitro and displayed potent ROCK inhibition. Topical administration of (S)-10e significantly lowered intraocular pressure in an acute ocular hypertension rabbit model and protected retinal ganglion cells in a magnetic microbead occlusion mouse model. A metabolism investigation revealed that (S)-10e released 7a, a metabolite after NO releasing, and 13, an active metabolite of (S)-Netarsudil, in rabbit eyes. Notably, introducing an NO donor moiety attenuated ROCK inhibition-induced ocular irritation in an sGC-independent manner, suggesting that the attenuated conjunctival hyperemia effect of (S)-10e is related to the NO-induced protein S-nitrosation of phosphodiesterase 3A (PDE3A). Overall, (S)-10e is a promising candidate for glaucoma treatment.

Novel mechanism of cyclic nucleotide crosstalk mediated by PKG-dependent proteasomal degradation of the Hsp90 client protein phosphodiesterase 3A

Endothelial cAMP-specific phosphodiesterase PDE3A is one of the major negative regulators of the endothelial barrier function in acute lung injury models. However, the mechanisms underlying its regulation still need to be fully resolved. We show here that the PDE3A is a newly described client of the molecular chaperone heat shock protein 90 (hsp90). In endothelial cells (ECs), hsp90 inhibition by geldanamycin (GA) led to a disruption of the hsp90/PDE3A complex, followed by a significant decrease in PDE3A protein levels. The decrease in PDE3A protein levels was ubiquitin-proteasome-dependent and required the activity of the E3 ubiquitin ligase C terminus of Hsc70-interacting protein. GA treatment also enhanced the association of PDE3A with hsp70, which partially prevented PDE3A degradation. GA-induced decreases in PDE3A protein levels correlated with decreased PDE3 activity and increased cAMP levels in EC. We also demonstrated that protein kinase G-dependent phosphorylation of PDE3A at Ser654 can signal the dissociation of PDE3A from hsp90 and PDE3A degradation. This was confirmed by endogenous PDE3A phosphorylation and degradation in 8-Br-cGMP- or 8-CPT-cGMP- and Bay 41-8543-stimulated EC and comparisons of WT- and phospho-mimic S654D mutant PDE3A protein stability in transiently transfected HEK293cells. In conclusion, we have identified a new mechanism of PDE3A regulation mediated by the ubiquitin-proteasome system. Further, the degradation of PDE3A is controlled by the phosphorylation of S654 and the interaction with hsp90. We speculate that targeting the PDE3A/hsp90 complex could be a therapeutic approach for acute lung injury.

A PDE3A-SLFN12 Molecular Glue Exhibits Significant Antitumor Activity in TKI-Resistant Gastrointestinal Stromal Tumors.

Gastrointestinal stromal tumor (GIST), the most common mesenchymal tumor with KIT or PDGFRA driver mutations, is typically treated with tyrosine kinase inhibitors (TKI). However, resistance to TKIs due to secondary mutations is a common challenge in advanced GISTs. In addition, there are currently no effective therapies for several other molecular subtypes, such as succinate dehydrogenase-deficient GISTs. Therefore, novel therapeutic strategies are needed. To address this need, we tested the efficacy of a novel non-TKI compound, OPB-171775, using patient-derived xenograft models of GISTs. In parallel, we sought to elucidate the mechanism of action of the compound. Our study revealed that OPB-171775 exhibited significant efficacy against GISTs regardless of their KIT mutation status by inducing complex formation between phosphodiesterase 3A (PDE3A) and Schlafen family member 12 (SLFN12), which are highly expressed in GISTs, leading to SLFN12 RNase-mediated cell death. Furthermore, we identified the activation of general control non-derepressible 2 and its downstream response as an effector pathway of SLFN12 in mediating anticancer activity and revealed potential pharmacodynamic markers. These findings suggest that OPB-171775, with its significant efficacy, could potentially serve as a novel and effective treatment option for advanced GISTs, particularly those resistant to TKIs.

Protein Kinase A Regulates Platelet Phosphodiesterase 3A through an A-Kinase Anchoring Protein Dependent Manner.

Platelet activation is critical for haemostasis, but if unregulated can lead to pathological thrombosis. Endogenous platelet inhibitory mechanisms are mediated by prostacyclin (PGI2)-stimulated cAMP signalling, which is regulated by phosphodiesterase 3A (PDE3A). However, spatiotemporal regulation of PDE3A activity in platelets is unknown. Here, we report that platelets possess multiple PDE3A isoforms with seemingly identical molecular weights (100 kDa). One isoform contained a unique N-terminal sequence that corresponded to PDE3A1 in nucleated cells but with negligible contribution to overall PDE3A activity. The predominant cytosolic PDE3A isoform did not possess the unique N-terminal sequence and accounted for >99% of basal PDE3A activity. PGI2 treatment induced a dose and time-dependent increase in PDE3A phosphorylation which was PKA-dependent and associated with an increase in phosphodiesterase enzymatic activity. The effects of PGI2 on PDE3A were modulated by A-kinase anchoring protein (AKAP) disruptor peptides, suggesting an AKAP-mediated PDE3A signalosome. We identified AKAP7, AKAP9, AKAP12, AKAP13, and moesin expressed in platelets but focussed on AKAP7 as a potential PDE3A binding partner. Using a combination of immunoprecipitation, proximity ligation techniques, and activity assays, we identified a novel PDE3A/PKA RII/AKAP7 signalosome in platelets that integrates propagation and termination of cAMP signalling through coupling of PKA and PDE3A.

METTL3's role in cervical cancer development through m6A modification.

N6-methylated adenosine (m6A) is a crucial RNA modification in eukaryotes, particularly in cancer. However, its role in cervical cancer (CC) is unclear. We aimed to elucidate the part of m6A in CC by analyzing methyltransferase-like 3 (METTL3) expression, identifying downstream targets, and exploring the underlying mechanism. We assessed METTL3 expression in CC using western blotting, quantitative polymerase chain reaction (qPCR), and immunohistochemistry. Invitro and invivo experiments examined METTL3's role in CC. We employed RNA sequencing, methylated RNA immunoprecipitation sequencing, qPCR, and RNA immunoprecipitation qPCR to explore METTL3's mechanism in CC. METTL3 expression was upregulated in CC, promoting cell proliferation and metastasis. METTL3 knockdown inhibited human cervical cancer by inactivating AKT/mTOR signaling pathway. METTL3-mediated m6A modification was observed in CC cells, targeting phosphodiesterase 3A (PDE3A). METTL3 catalyzed m6A modification on PDE3A mRNA through YTH domain family protein 3 (YTHDF3). Our study indicated the mechanism of m6A modification in CC and suggested the METTL3/YTHDF3/PDE3A axis as a potential clinical target for CC treatment.

Partially Differentiated Ileal and Rectal Human CFTR-F508del Enteroids Secrete Fluid in Response to cAMP and cGMP: Targeted Preclinical Studies of Pharmaco-Therapy of CF Constipation

Introduction: Treatment of Cystic Fibrosis (CF) patients with Trikafta is prolonging life. This has allowed the importance of other causes of morbidity in these patients to become clearer and to emphasize the need to improve their quality of life by developing additional treatments. Chronic constipation is one such continuing unsolved medical issue for patients with CF even on Trikafta. In general, approaches to treat chronic constipation include increasing intestinal fluid secretion that involves inhibiting intestinal NaCl absorption and/or stimulating intestinal Cl secretion, with inhibition of the latter being the primary defect in CF. Drug development efforts have mostly aimed to improve CFTR function and control pancreatic insuffciency. We have recently reported an enterocyte population in the human ileal and colon that is present between the crypt Cl− secretory cells and the mature small intestinal villus or colonic surface Na+ absorptive cells that contain both DRA and CFTR. This population is called partially differentiated enterocytes. This study was undertaken to derive a strategy to stimulate intestinal fluid secretion from partially differentiated enterocytes in the F508del-CF-patient population by enhancing residual CFTR F508del activity using drugs that stimulate cAMP and cGMP. Methods: Ileal and rectal enteroids from F508del CF patients and healthy subjects (HS/normal) were studied. Enteroids were maintained in growth media containing Wnt3A, R-spondin, and Noggin (undifferentiated/UD); induced to partially differentiate (3d-DF) or fully differentiate (6d-DF) by removal of growth factors (Wnt3A and R-spondin) for 3 or 6 days, respectively. Forskolin-induced swelling (FIS) assay and live cell microscopy were used to determine fluid secretion in enteroids. A relative increase in organoid surface area over a time series of 60 min was measured to quantify FIS response. mRNA expression was determined using qRT-PCR. Results: Compared to HS enteroids, F508del enteroids had significantly higher mRNA expression of LGR5, and Ki67 in the UD state. Expression of goblet cell marker MUC2 and enteroendocrine (EEC) marker ChgA increased with differentiation in both HS and F508del, while 6d-DF F508del enteroids had a significantly higher ChgA compared to 6d-DF enteroids from HS. UD F508del enteroids had significantly higher expression of phosphodiesterase-3a (PDE3a) than HS enteroids, which further increased with differentiation, but did not change in HS. While UD and 6d-DF F508del rectal and ileal enteroids did not swell when exposed to cAMP (forskolin) and cGMP (linaclotide), 3d-DF F508del enteroids showed a swelling response when exposed to cAMP (forskolin) and cGMP (linaclotide). Fluid secretion from 3d-DF F508del enteroids was ~50% (cAMP) and ~67% (cGMP) of the response of intestinal enteroids from HS enteroids. Combinations of CFTR correctors and potentiators mimicking the makeup of Trikafta only partially enhanced fluid secretion in F508del CF enteroids as compared to HS. However, cGMP (linaclotide) additively enhanced Trikafta-induced fluid secretion from 3d-DF F508del enteroids. Conclusions: CFTR F508del can be stimulated by cAMP and cGMP in partially differentiated enterocyte populations. Our findings identify a novel role of the partially differentiated ileal and rectal enterocyte populations which behave in a way that offers the potential to improve treatment for CF constipation. Funding: This study is partly supported by Cystic Fibrosis Foundation grant CF-SINGH20G0, National Institutes of Health grants R01-DK-116352 and P30-DK-89502 (the Hopkins Basic and Translational Research Digestive Diseases Research Core Center). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Toxic effect and mechanism of β-cypermethrin and its chiral isomers on HTR-8/SVneo cells

Beta-cypermethrin (β-CYP) consists of four chiral isomers, acting as an environmental estrogen and causing reproductive toxicity, neurotoxicity, and dysfunctions in multiple organ systems. This study investigated the toxic effects of β-CYP, its isomers, metabolite 3-phenoxybenzoic acid (3-PBA), and 17β-estradiol (E2) on HTR-8/SVneo cells. We focused on the toxic mechanisms of β-CYP and its specific isomers. Our results showed that β-CYP and its isomers inhibit HTR-8/SVneo cell proliferation similarly to E2, with 100 μM 1S-trans-αR displaying significant toxicity after 48 h. Notably, 1S-trans-αR, 1R-trans-αS, and β-CYP were more potent in inducing apoptosis and cell cycle arrest than 1R-cis-αS and 1S-cis-αR at 48 h. AO/EB staining and flow cytometry indicated dose-dependent apoptosis in HTR-8/SVneo cells, particularly at 100 μM 1R-trans-αS. Scratch assays revealed that β-CYP and its isomers variably reduced cell migration. Receptor inhibition assays demonstrated that post-ICI 182780 treatment, which inhibits estrogen receptor α (ERα) or estrogen receptor β (ERβ), β-CYP, its isomers, and E2 reduced HTR-8/SVneo cell viability, whereas milrinone, a phosphodiesterase 3 A (PDE3A) inhibitor, increased viability. Molecular docking studies indicated a higher affinity of β-CYP, its isomers, and E2 for PDE3A than for ERα or ERβ. Consequently, β-CYP, its isomers, and E2 consistently led to decreased cell viability. Transcriptomics and RT-qPCR analyses showed differential expression in treated cells: up-regulation of Il24 and Ptgs2, and down-regulation of Myo7a and Pdgfrb, suggesting the PI3K-AKT signaling pathway as a potential route for toxicity. This study aims to provide a comprehensive evaluation of the cytotoxicity of chiral pesticides and their mechanisms.

The Sleep Quality- and Myopia-Linked PDE11A-Y727C Variant Impacts Neural Physiology by Reducing Catalytic Activity and Altering Subcellular Compartmentalization of the Enzyme.

Recently, a Y727C variant in the dual-specific 3',5'-cyclic nucleotide phosphodiesterase 11A (PDE11A-Y727C) was linked to increased sleep quality and reduced myopia risk in humans. Given the well-established role that the PDE11 substrates cAMP and cGMP play in eye physiology and sleep, we determined if (1) PDE11A protein is expressed in the retina or other eye segments in mice, (2) PDE11A-Y7272C affects catalytic activity and/or subcellular compartmentalization more so than the nearby suicide-associated PDE11A-M878V variant, and (3) Pde11a deletion alters eye growth or sleep quality in male and female mice. Western blots show distinct protein expression of PDE11A4, but not PDE11A1-3, in eyes of Pde11a WT, but not KO mice, that vary by eye segment and age. In HT22 and COS-1 cells, PDE11A4-Y727C reduces PDE11A4 catalytic activity far more than PDE11A4-M878V, with both variants reducing PDE11A4-cAMP more so than PDE11A4-cGMP activity. Despite this, Pde11a deletion does not alter age-related changes in retinal or lens thickness or axial length, nor vitreous or anterior chamber depth. Further, Pde11a deletion only minimally changes refractive error and sleep quality. That said, both variants also dramatically alter the subcellular compartmentalization of human and mouse PDE11A4, an effect occurring independently of dephosphorylating PDE11A4-S117/S124 or phosphorylating PDE11A4-S162. Rather, re-compartmentalization of PDE11A4-Y727C is due to the loss of the tyrosine changing how PDE11A4 is packaged/repackaged via the trans-Golgi network. Therefore, the protective impact of the Y727C variant may reflect a gain-of-function (e.g., PDE11A4 displacing another PDE) that warrants further investigation in the context of reversing/preventing sleep disturbances or myopia.

Abstract B028: Phosphodiesterase 3A modulators sensitize tumor cells to Bcl-2/Bcl-xL inhibitors

Abstract Phosphodiesterase 3A (PDE3A) modulators are promising anticancer agents for tumors that coexpress PDE3A and Schlafen 12 (SLFN12), including sarcomas. The cytotoxic effect of these modulators is based on their ability to form a complex between PDE3A and SLFN12, and correlates with the expression levels of the two proteins. In cases where the two proteins are only moderately expressed, PDE3A modulator efficacy may remain poor and additional therapeutic options are needed. In this study, we investigated the combinatorial effects of a PDE3A modulator, anagrelide, with 526 other oncological compounds in two PDE3A and SLFN12 expressing liposarcoma cell lines (SA4 and GOT3). Both cell lines were responsive to PDE3A modulators, as expected. Interestingly, we found synergy with seven different drug classes that can be grouped based on their protein and protein family targets: Bcl-2l/Bcl-xL, HDAC, integrin α2 (ITGA2), mTOR, NEDD-activating enzyme E1 regulatory subunit proteins, and PAK. Additional detailed drug combination synergy studies in PDE3A modulator –sensitive liposarcoma, gastrointestinal stromal tumor, melanoma, and astrocytoma cell lines indicated a sensitizing effect of PDE3A modulators to Bcl-2/Bcl-xL inhibitors. These cell lines, excluding GOT3, showed no response to Bcl-2/Bcl-xL inhibitors otherwise. Furthermore, we discovered that the sensitization effect depends on the coexpression of PDE3A and SLFN12, and that cotreatment resulted in stronger activation of programmed cell death. Our findings suggest additional combinatorial opportunities between PDE3A modulators and inhibitors of key cancer pathways that could be explored for their therapeutic value. Citation Format: Kirsi L. J. Toivanen, Astrid Murumägi, Mariliina A. Arjama, Nanna J. Merikoski, Sami I. Salmikangas, Olli P. Kallioniemi, Tom O. Böhling, Harri J. Sihto. Phosphodiesterase 3A modulators sensitize tumor cells to Bcl-2/Bcl-xL inhibitors [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr B028.

Abstract A030: Treatment with sustained-release anagrelide reduces tumor volume and has antiproliferative effects in a patient-derived GIST xenograft mouse model

Abstract Anagrelide is a phosphodiesterase 3A inhibitor that is used to treat essential thrombocythemia. The drug stabilizes the interaction of PDE3A and Schlafen 12 (SLFN12), resulting in complex stabilization, activation of SLFN12 RNase activity and cytotoxic effects in cancer cells. Gastrointestinal stromal tumors (GIST) exhibit high levels of PDE3A expression compared to other cancers or healthy tissue. Orally administered anagrelide has shown antitumor effects in patient-derived GIST xenograft (PDX) mouse models. In this study, we investigated the efficacy of subcutaneously administered, sustained-release anagrelide in UZLX-GIST2B, a PDX mouse model characterized by a KIT mutation in exon 9 and typical dose-dependent imatinib sensitivity. We assessed changes in tumor volume and evaluated histological drug responses including hyalinization, fibrosis, myxoid generation, and tumor necrosis. Anagrelide was administered either orally (2.5 mg/kg, twice a day) or subcutaneously (35 mg/kg and 70 mg/kg, every fourth day) for a duration of 11 days. Treatments with both 35 mg/kg and 70 mg/kg doses resulted in a significant reduction in average tumor volume compared to untreated control mice (both doses 25% vs.129%, P < 0.001) or mice treated with oral anagrelide (25% vs. 61%, P =0 .08, P < 0.05, respectively). The histological response in tumor tissue was positively correlated with dose level, and tumors treated with the highest dose exhibited grade 3 to 4 responses in all cases. These results suggest that sustained-release anagrelide holds promise as a therapeutic option for the treatment of GIST. Further preclinical studies are warranted to investigate the pharmacokinetics and toxicity of this treatment approach. Citation Format: Kirsi Toivanen, Luna De Sutter, Agnieszka Wozniak, Tom Böhling, Patrick Schöffski, Harri Sihto. Treatment with sustained-release anagrelide reduces tumor volume and has antiproliferative effects in a patient-derived GIST xenograft mouse model [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr A030.

Phosphodiesterase 3A Acts As a Tumor Activator and Its Inhibitor Anagrelide Combined with Idarubicin Represents a Potential Therapeutic Approach for PDE3A High Expressed Acute Myeloid Leukemia through Pyroptosis By Triggering Cleavage of Gasdermin E

Acute myeloid leukemia (AML) is a clinically aggressive and heterogeneous hematologic neoplasm with a poor overall outcome. Platelets can interact with malignant cells including leukemic blasts and play a crucial role in cancer progression, metastasis and angiogenesis, budding of platelet microparticles can transfer a plethora of bioactive molecules to cancer cells upon internalization and in AML this can induce chemoresistance. Anti-platelet therapy using Phosphodiesterase 3A (PDE3A) inhibitors, such as anagrelide (ANA), holds promise in tumor elimination. Additionally, upregulation of PDE3A in solid tumors is associated with a poor prognosis in patients and activates inflammatory pathways, impacting cancer cell stemness. However, the role of PDE3A in AML remains unclear. This study aims to investigate the correlation between PDE3A expression and AML prognosis, as well as to characterize the feasibility and mechanism of ANA as a potential anti-leukemia therapy and its synergistic effect to chemotherapeutic drugs. To explore the correlation between PDE3A expression and AML prognosis, we initially analyzed its expression in AML patients and healthy donors from the Children's Hospital of Soochow University. The results demonstrated significantly higher levels of PDE3A in bone marrow mononuclear cells (BMMNCs) from AML patients, both at the protein and mRNA levels, compared to BMMNCs from healthy donors. Subsequently, we investigated PDE3A expression and survival data of 152 AML patients from our center, revealing that patients with high PDE3A expression exhibited significantly lower overall survival (OS), relapse-free survival (RFS), and event-free survival (EFS) compared to those with low PDE3A expression. These findings were further corroborated by data from other databases (R2 and GEPIA), confirming the significant role of PDE3A in AML. Among AML cell lines, HEL and MOLM-16 cells exhibited notably higher PDE3A expression at both the protein and mRNA levels, which were chosen for further study. ANA treatment specifically inhibited the proliferation of PDE3A-high-expressing AML cells but not low expression cells in vitro, which was further confirmed in the HEL-mediated xenograft leukemia model. Notably, the RNA sequencing data revealed ANA treatment significantly downregulated several chemotherapy-resistant genes, including PAK1, HMGCS1, p-SRC, DUSP16 and EGR1, indicating ANA has the potential to synergize with chemotherapeutic drugs for AML therapy. Therefore, we combine ANA and chemotherapy drugs to investigate the synergetic inhibitory effect. IDA with ANA simultaneously exerted the strongest synergistic effect among the six anti-leukemia drugs depend on the judgement of CI value and had the synergistic effect in HEL, MOLM-16 and primary cells from PDE3A high expressed AML patients. The GSEA analysis of RNA sequencing data showed that the IDA-ANA combination treatment led to a significant enrichment of the inflammatory response. Moreover, at the protein level, pyroptosis-related proteins including NLRP3, Cleaved-CASP3, Cleaved-CASP8 and GSDME-N were notably upregulated in IDA-ANA combination group compared to IDA or ANA group. Finally, we established an AML xenograft mouse model using the HEL cell line and administered different treatments: vehicle (control), IDA (0.5 mg/kg), ANA (5 mg/kg), or the indicated combination of IDA and ANA. The results demonstrated that the IDA-ANA combination treatment significantly extended the survival time of the mice and reduced the leukemia burden when compared to the individual treatments with either IDA or ANA. In second HEL xenograft mice study, separate cohorts of vehicle and drug treated mice were sacrificed and leukemic livers as well as spleens were harvested and weighed, the IDA-ANA combination treated mice exhibited smaller and lighter livers and spleens than the other groups and controls. HE results explained the histological decrease of HEL cells infiltration of IDA-ANA combination treatment in the livers, spleens and bone marrow compared with the treatment of IDA or ANA. Congruently, the analysis of IHC confirmed the same result. In summary, high expression of PDE3A related to poor prognosis in AML and PDE3A inhibitor ANA combined with IDA exerted anti-leukemia effect through pyroptosis on PDE3A high expressed AML. Our findings represent a potential therapeutic regimen for AML.

First Optimization of Novel, Potent, Selective PDE11A4 Inhibitors for Age-Related Cognitive Decline.

Phosphodiesterase 11A4 (PDE11A4) is a dual-acting cyclic nucleotide hydrolase expressed in neurons in the CA1, subiculum, amygdalostriatal transition area and amygdalohippocampal area of the extended hippocampal formation. PDE11A4 is the only PDE enzyme to emanate solely from hippocampal formation, a key brain region for the formation of long-term memory. PDE11A4 expression increases in the hippocampal formation of both humans and rodents as they age. Interestingly, PDE11A knockout mice do not show age-related deficits in associative memory and show no gross histopathology. This suggests that inhibition of PDE11A4 might serve as a therapeutic option for age-related cognitive decline. A novel, yeast-based high throughput screen previously identified moderately potent, selective PDE11A4 inhibitors, and this work describes initial efforts that improved potency more than 10-fold and improved some pharmaceutical properties of one of these scaffolds, leading to selective, cell-penetrant PDE11A4 inhibitors, one of which is 10-fold more potent compared to tadalafil in cell-based activity.

Mesenchymal stem cell-derived extracellular vesicles prevent the formation of pulmonary arterial hypertension through a microRNA-200b-dependent mechanism

BackgroundBone marrow mesenchymal stem cell-derived extracellular vesicles (BMSC-EVs) have been highly studied with their critical roles as carriers of therapeutic targets such as microRNAs (miRNAs) in the treatment of human diseases, including pulmonary arterial hypertension (PAH). Herein, we tried to study the potential of BMSC-EVs to deliver miR-200b for the regulation of macrophage polarization in PAH.MethodsRat models of PAH were induced with monocrotaline treatment, followed by miR-200b expression detection in lung tissues, pulmonary artery smooth muscle cells (PASMCs) and macrophages. miR-200b-containing BMSCs or miR-200b-deficient BMSCs were selected to extract EVs. Then, we assessed the changes in rats with PAH-associated disorders as well as in vitro macrophage polarization and the functions of PASMCs after treatment with BMSC-EVs. Moreover, the interaction between miR-200b, phosphodiesterase 1 A (PDE1A) was identified with a luciferase assay, followed by an exploration of the downstream pathway, cAMP-dependent protein kinase (PKA).ResultsmiR-200b was reduced in lung tissues, PASMCs and macrophages of rats with PAH-like pathology. BMSC-EVs transferred miR-200b into macrophages, and subsequently accelerated their switch to the M2 phenotype and reversed the PAH-associated disorders. Furthermore, miR-200b carried by BMSC-EVs induced PKA phosphorylation by targeting PDE1A, thereby expediting macrophage polarization.ConclusionOur current study highlighted the inhibitory role of BMSC-EV-miR-200b in PAH formation.

Cyclic thrombocytopenia associated with estradiol: a case report

ABSTRACTObjectivesCyclic thrombocytopenia (CTP) is a rare blood disorder characterized by periodic fluctuations in platelet counts. CTP usually appears in pre-menopausal women, and these fluctuations of platelets are in phase with the menstrual cycle. CTP is a heterogeneous disease, and the pathogenic mechanism is still unclear. Therefore, it harbors great significance for exploring the association of fluctuations in platelet counts with hormonal-cycle.MaterialsFirstly, we washed human platelets from healthy volunteers following the Declaration of Helsinki. Flow cytometer was employed to measure the mitochondrial inner transmembrane potential (ΔΨm) depolarization, PS exposure, P-selectin expression, and GPIIb/IIIa activation in platelets. In addition, western blot detected the related protein expression. The corresponding assay kit measured the caspase-3 and PDE3A activity. Finally, flow cytometry determined mouse platelets labeled with calcein.ResultsWe find a reverse relationship between the platelet count and serum estradiol (E2) level in a CTP patient. We demonstrated that E2 induces platelet apoptosis in vitro and platelet clearance in vivo. We further discovered that E2 activates phosphodiesterase 3A, which inhibits protein kinase A (PKA), leading to PKA-mediated platelet apoptosis. Activation of PKA protected platelets from E2-induced thrombocytopenia and elevated the number of mice circulatory platelets.ConclusionsWe find that E2 induces platelet apoptosis and clearance through PDE3A-mediated PKA inhibition. Activation of PKA rescues E2-induced thrombocytopenia in mice. Thus, our study reveals a pathogenesis of E2-related CTP and suggests promising therapeutic strategies for the disease.

Biologic that disrupts PDE11A4 homodimerization in hippocampus CA1 reverses age-related cognitive decline of social memories in mice

Age-related abnormalities in phosphodiesterase 11A (PDE11A), which degrades 3′,5′-cAMP/cGMP and is enriched in the ventral hippocampus (VHIPP), drive age-related cognitive decline (ARCD) of social memories. Age-related PDE11A4 ectopically accumulates within the membrane compartment and in filamentous structures termed ghost axons. Previous studies show that expressing an isolated PDE11A4-GAF-B binding domain disrupts homodimerization and reverses aging-like PDE11A4 accumulations in vitro. Here, we show that in vivo lentiviral expression of the isolated PDE11A4-GAFB domain in hippocampal CA1 of aged mice reverses age-related PDE11A4 accumulations and ARCD of social transmission of food preference memory (STFP). It also improves 7-day remote long-term memory for social odor recognition without affecting non-social odor recognition. In vitro studies show that disrupting homodimerization does not alter the catalytic activity of PDE11A4 but may reverse age-related decreases in cGMP by relocating PDE11A4 from a cGMP-rich to a cAMP-rich pool independently of other intramolecular relocation signals (PDE11A4-pS162). Altogether, these data suggest that a biologic designed to disrupt PDE11A4 homodimerization may hold therapeutic potential for age-related PDE11A4 proteinopathies.

Exploring the Molecular Targets for the Antidepressant and Antisuicidal Effects of Ketamine Enantiomers by Using Network Pharmacology and Molecular Docking.

Ketamine, a racemic mixture of esketamine (S-ketamine) and arketamine (R-ketamine), has received particular attention for its rapid antidepressant and antisuicidal effects. NMDA receptor inhibition has been indicated as one of the main mechanisms of action of the racemic mixture, but other pharmacological targets have also been proposed. This study aimed to explore the possible multiple targets of ketamine enantiomers related to their antidepressant and antisuicidal effects. To this end, targets were predicted using Swiss Target Prediction software for each ketamine enantiomer. Targets related to depression and suicide were collected by the Gene Cards database. The intersections of targets were analyzed using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). Network pharmacology analysis was performed using Gene Mania and Cytoscape software. Molecular docking was used to predict the main targets of the network. The results indicated that esketamine and arketamine share some biological targets, particularly NMDA receptor and phosphodiesterases 3A, 7A, and 5A but have specific molecular targets. While esketamine is predicted to interact with the GABAergic system, arketamine may interact with macrophage migration inhibitory factor (MIF). Both ketamine enantiomers activate neuroplasticity-related signaling pathways and show addiction potential. Our results identified novel, poorly explored molecular targets that may be related to the beneficial effects of esketamine and arketamine against depression and suicide.