Phosphodiesterase 3B (PDE3B) antagonizes the anti-angiogenic actions of PKA in human and murine endothelial cells

The Progression of Mycosis Fungoides During Treatment with Mogamulizumab: A BIO-MUSE Case Study of the Tumor and Immune Response in Peripheral Blood and Tissue

Background/objectives: Mycosis fungoides (MF) is a rare malignancy, with an indolent course in the early stages of the disease. However, due to major molecular and clinical heterogeneity, patients at an advanced stage of the disease have variable responses to treatment and considerably reduced life expectancy. Today, there is a lack of specific markers for the progression from early to advanced stages of the disease. To address these challenges, the non-interventional BIO-MUSE trial was initiated. Here, we report on a case study involving one patient, where combined omics analysis of tissue and blood was used to reveal the unique molecular features associated with the progression of the disease. Methods: We applied 10× genomics-based single-cell RNA sequencing to CD3+ peripheral T-cells, combined with T-cell receptor sequencing, to samples collected at multiple timepoints during the progression of the disease. In addition, GeoMx-based digital spatial profiling of T-helper (CD3+/CD8-), T-cytotoxic (CD3+/CD8+), and CD163+ cells was performed on skin biopsies. Results. The results pinpoint targets, such as transforming growth factor β1, as some of the mechanisms underlying disease progression, which may have the potential to improve patient prognostication and the development of precision medicine efforts. Conclusions: We propose that in patients with MF, the evolution of the malignant clone and the associated immune response need to be studied jointly to define relevant strategies for intervention.

Targeting the PDE3B-cAMP-autophagy axis prevents liver injury in long-term supercooling liver preservation

In liver transplantation, donor livers are typically stored in a preservation solution at 4°C for up to 12 hours. However, this short preservation duration can lead to various issues, such as suboptimal donor-recipient matching and limited opportunities for organ sharing. Previous studies have developed a long-term preservation method called supercooling liver preservation (SLP) to address these issues. However, in this study using a rat model, we observed that long-term SLP led to more severe liver damage compared with clinically prevalent traditional static cold storage (SCS) for durations less than 8 hours. To understand the potential mechanism of SLP-induced liver injury, we conducted an integrative metabolomic, transcriptomic, and proteomic analysis. We identified the PDE3B-cAMP-autophagy pathway as a key determinant of SLP-induced liver injury. Specifically, we found that PDE3B was elevated during SLP, which promoted a reduction of cAMP metabolites, triggering an AMPK-dependent autophagy process that led to liver injury in rats. We found that blocking the reduction in cAMP using the PDE3B inhibitor cilostamide inhibited autophagy and substantially ameliorated liver injury during 48-hour SLP in rat livers. Furthermore, we validated the effectiveness of cilostamide treatment in preventing liver injury in pig and human liver 48-hour SLP models. In summary, our results reveal that metabolic reprogramming involving the PDE3B-cAMP-autophagy axis is the key determinant of liver injury in long-term SLP and provide an early therapeutic strategy to prevent liver injury in this setting.

Accurate breast cancer diagnosis using a stable feature ranking algorithm

BACKGROUND

Breast cancer (BC) is one of the most common cancers among women. Since diverse features can be collected, how to stably select the powerful ones for accurate BC diagnosis remains challenging.

METHODS

A hybrid framework is designed for successively investigating both feature ranking (FR) stability and cancer diagnosis effectiveness. Specifically, on 4 BC datasets (BCDR-F03, WDBC, GSE10810 and GSE15852), the stability of 23 FR algorithms is evaluated via an advanced estimator (S), and the predictive power of the stable feature ranks is further tested by using different machine learning classifiers.

RESULTS

Experimental results identify 3 algorithms achieving good stability ([Formula: see text]) on the four datasets and generalized Fisher score (GFS) leading to state-of-the-art performance. Moreover, GFS ranks suggest that shape features are crucial in BC image analysis (BCDR-F03 and WDBC) and that using a few genes can well differentiate benign and malignant tumor cases (GSE10810 and GSE15852).

CONCLUSIONS

The proposed framework recognizes a stable FR algorithm for accurate BC diagnosis. Stable and effective features could deepen the understanding of BC diagnosis and related decision-making applications.

cAMP Compartmentalization in Cerebrovascular Endothelial Cells: New Therapeutic Opportunities in Alzheimer's Disease

The vascular hypothesis used to explain the pathophysiology of Alzheimer’s disease (AD) suggests that a dysfunction of the cerebral microvasculature could be the beginning of alterations that ultimately leads to neuronal damage, and an abnormal increase of the blood–brain barrier (BBB) permeability plays a prominent role in this process. It is generally accepted that, in physiological conditions, cyclic AMP (cAMP) plays a key role in maintaining BBB permeability by regulating the formation of tight junctions between endothelial cells of the brain microvasculature. It is also known that intracellular cAMP signaling is highly compartmentalized into small nanodomains and localized cAMP changes are sufficient at modifying the permeability of the endothelial barrier. This spatial and temporal distribution is maintained by the enzymes involved in cAMP synthesis and degradation, by the location of its effectors, and by the existence of anchor proteins, as well as by buffers or different cytoplasm viscosities and intracellular structures limiting its diffusion. This review compiles current knowledge on the influence of cAMP compartmentalization on the endothelial barrier and, more specifically, on the BBB, laying the foundation for a new therapeutic approach in the treatment of AD.

Protein kinase A negatively regulates VEGF-induced AMPK activation by phosphorylating CaMKK2 at serine 495

Activation of AMP-activated protein kinase (AMPK) in endothelial cells by vascular endothelial growth factor (VEGF) via the Ca2+/calmodulin-dependent protein kinase kinase 2 (CaMKK2) represents a pro-angiogenic pathway, whose regulation and function is incompletely understood. This study investigates whether the VEGF/AMPK pathway is regulated by cAMP-mediated signalling. We show that cAMP elevation in endothelial cells by forskolin, an activator of the adenylate cyclase, and/or 3-isobutyl-1-methylxanthine (IBMX), an inhibitor of phosphodiesterases, triggers protein kinase A (PKA)-mediated phosphorylation of CaMKK2 (serine residues S495, S511) and AMPK (S487). Phosphorylation of CaMKK2 by PKA led to an inhibition of its activity as measured in CaMKK2 immunoprecipitates of forskolin/IBMX-treated cells. This inhibition was linked to phosphorylation of S495, since it was not seen in cells expressing a non-phosphorylatable CaMKK2 S495C mutant. Phosphorylation of S511 alone in these cells was not able to inhibit CaMKK2 activity. Moreover, phosphorylation of AMPK at S487 was not sufficient to inhibit VEGF-induced AMPK activation in cells, in which PKA-mediated CaMKK2 inhibition was prevented by expression of the CaMKK2 S495C mutant. cAMP elevation in endothelial cells reduced basal and VEGF-induced acetyl-CoA carboxylase (ACC) phosphorylation at S79 even if AMPK was not inhibited. Together, this study reveals a novel regulatory mechanism of VEGF-induced AMPK activation by cAMP/PKA, which may explain, in part, inhibitory effects of PKA on angiogenic sprouting and play a role in balancing pro- and anti-angiogenic mechanisms in order to ensure functional angiogenesis.

Therapeutic Potential of Phosphodiesterase Inhibitors for Endothelial Dysfunction- Related Diseases

Cardiovascular diseases (CVD) are considered a major health problem worldwide, being the main cause of mortality in developing and developed countries. Endothelial dysfunction, characterized by a decline in nitric oxide production and/or bioavailability, increased oxidative stress, decreased prostacyclin levels, and a reduction of endothelium-derived hyperpolarizing factor is considered an important prognostic indicator of various CVD. Changes in cyclic nucleotides production and/ or signalling, such as guanosine 3', 5'-monophosphate (cGMP) and adenosine 3', 5'-monophosphate (cAMP), also accompany many vascular disorders that course with altered endothelial function. Phosphodiesterases (PDE) are metallophosphohydrolases that catalyse cAMP and cGMP hydrolysis, thereby terminating the cyclic nucleotide-dependent signalling. The development of drugs that selectively block the activity of specific PDE families remains of great interest to the research, clinical and pharmaceutical industries. In the present review, we will discuss the effects of PDE inhibitors on CVD related to altered endothelial function, such as atherosclerosis, diabetes mellitus, arterial hypertension, stroke, aging and cirrhosis. Multiple evidences suggest that PDEs inhibition represents an attractive medical approach for the treatment of endothelial dysfunction-related diseases. Selective PDE inhibitors, especially PDE3 and PDE5 inhibitors are proposed to increase vascular NO levels by increasing antioxidant status or endothelial nitric oxide synthase expression and activation and to improve the morphological architecture of the endothelial surface. Thereby, selective PDE inhibitors can improve the endothelial function in various CVD, increasing the evidence that these drugs are potential treatment strategies for vascular dysfunction and reinforcing their potential role as an adjuvant in the pharmacotherapy of CVD.

Cardiac Cyclic Nucleotide Phosphodiesterases: Roles and Therapeutic Potential in Heart Failure

The cyclic nucleotides cyclic adenosine-3′,5′-monophosphate (cAMP) and cyclic guanosine-3′,5′-monophosphate (cGMP) maintain physiological cardiac contractility and integrity. Cyclic nucleotide–hydrolysing phosphodiesterases (PDEs) are the prime regulators of cAMP and cGMP signalling in the heart. During heart failure (HF), the expression and activity of multiple PDEs are altered, which disrupt cyclic nucleotide levels and promote cardiac dysfunction. Given that the morbidity and mortality associated with HF are extremely high, novel therapies are urgently needed. Herein, the role of PDEs in HF pathophysiology and their therapeutic potential is reviewed. Attention is given to PDEs 1–5, and other PDEs are briefly considered. After assessing the role of each PDE in cardiac physiology, the evidence from pre-clinical models and patients that altered PDE signalling contributes to the HF phenotype is examined. The potential of pharmacologically harnessing PDEs for therapeutic gain is considered.