Progress on the development of Class A GPCR-biased ligands.

Class A G protein-coupled receptors (GPCRs) continue to garner interest for their essential roles in cell signalling and their importance as drug targets. Although numerous drugs in the clinic target these receptors, over 60% GPCRs remain unexploited. Moreover, the adverse effects triggered by the available unbiased GPCR modulators, limit their use and therapeutic value. In this context, the elucidation of biased signalling has opened up new pharmacological avenues holding promise for safer therapeutics. Functionally selective ligands favour receptor conformations facilitating the recruitment of specific effectors and the modulation of the associated pathways. This review surveys the current drug discovery landscape of GPCR-biased modulators with a focus on recent advances. Understanding the biological effects of this preferential coupling is at different stages depending on the Class A GPCR family. Therefore, with a focus on individual GPCR families, we present a compilation of the functionally selective modulators reported over the past few years. In doing so, we dissect their therapeutic relevance, molecular determinants and potential clinical applications.

The Potential of Metabolomics to Find Proper Biomarkers for Addressing the Neuroprotective Efficacy of Drugs Aimed at Delaying Parkinson's and Alzheimer's Disease Progression.

The first objective is to highlight the lack of tools to measure whether a given intervention affords neuroprotection in patients with Alzheimer's or Parkinson's diseases. A second aim is to present the primary outcome measures used in clinical trials in cohorts of patients with neurodegenerative diseases. The final aim is to discuss whether metabolomics using body fluids may lead to the discovery of biomarkers of neuroprotection. Information on the primary outcome measures in clinical trials related to Alzheimer's and Parkinson's disease registered since 2018 was collected. We analysed the type of measures selected to assess efficacy, not in terms of neuroprotection since, as stated in the aims, there is not yet any marker of neuroprotection. Proteomic approaches using plasma or CSF have been proposed. PET could estimate the extent of lesions, but disease progression does not necessarily correlate with a change in tracer uptake. We propose some alternatives based on considering the metabolome. A new opportunity opens with metabolomics because there have been impressive technological advances that allow the detection, among others, of metabolites related to mitochondrial function and mitochondrial structure in serum and/or cerebrospinal fluid; some of the differentially concentrated metabolites can become reliable biomarkers of neuroprotection.

Homodimerization of CB2 cannabinoid receptor triggered by a bivalent ligand enhances cellular signaling.

G protein-coupled receptors (GPCRs) exist within a landscape of interconvertible conformational states and in dynamic equilibrium between monomers and higher-order oligomers, both influenced by ligand binding. Here, we show that a homobivalent ligand formed by equal chromenopyrazole moieties as pharmacophores, connected by 14 methylene units, can modulate the dynamics of the cannabinoid CB2 receptor (CB2R) homodimerization by simultaneously binding both protomers of the CB2R-CB2R homodimer. Computational and pharmacological experiments showed that one of the ligand pharmacophores binds to the orthosteric site of one protomer, and the other pharmacophore to a membrane-oriented pocket between transmembranes 1 and 7 of the partner protomer. This results in unique pharmacological properties, including increased potency in Gi-mediated signaling and enhanced recruitment of ß-arrestin. Thus, by modulating dimerization dynamics, it may be possible to fine-tune CB2R activity, potentially leading to improved therapeutic outcomes.

Allosterism in the adenosine A2A and cannabinoid CB2 heteromer.

BACKGROUND AND PURPOSE: Allosterism is a regulatory mechanism for GPCRs that can be attained by ligand-binding or protein-protein interactions with another GPCR. We have studied the influence of the dimer interface on the allosteric properties of the A2A receptor and CB2 receptor heteromer. EXPERIMENTAL APPROACH: We have evaluated cAMP production, phosphorylation of signal-regulated kinases (pERK1/2), label-free dynamic mass redistribution, ß-arrestin 2 recruitment and bimolecular fluorescence complementation assays in the absence and presence of synthetic peptides that disrupt the formation of the heteromer. Molecular dynamic simulations provided converging evidence that the heteromeric interface influences the allosteric properties of the A2AR-CB2R heteromer. KEY RESULTS: Apo A2AR blocks agonist-induced signalling of CB2R. The disruptive peptides, with the amino acid sequence of transmembrane (TM) 6 of A2AR or CB2R, facilitate CB2R activation, suggesting that A2AR allosterically prevents the outward movement of TM 6 of CB2R for G protein binding. Significantly, binding of the selective antagonist SCH 58261 to A2AR also facilitated agonist-induced activation of CB2R. CONCLUSIONS AND IMPLICATIONS: It is proposed that the A2AR-CB2R heteromer contains distinct dimerization interfaces that govern its functional properties. The molecular interface between protomers of the A2AR-CB2R heteromer interconverted from TM 6 for apo or agonist-bound A2AR, blocking CB2R activation, to mainly the TM 1/7 interface for antagonist-bound A2AR, facilitating the independent opening of intracellular cavities for G protein binding. These novel results shed light on a different type of allosteric mechanism and extend the repertoire of GPCR heteromer signalling.

Neuroprotective compounds alter the expression of genes coding for proteins related to mitochondrial function in activated microglia.

A hallmark of neuroinflammatory disorders is mitochondrial dysfunction. Nevertheless, the transcriptional changes underlying this alteration are not well-defined. Microglia activation, a decrease in mitochondrion biogenesis and a subsequent alteration of the redox are common factors in diseases coursing with neuroinflammation. In the last two decades, components of the adenosinergic system have been proposed as potential therapeutic targets to combat neuroinflammation. In this research, we analyzed by RNAseq the gene expression in activated microglia treated with an adenosine A2A receptor antagonist, SCH 582561, and/or an A3 receptor agonist, 2-Cl-IB-MECA, since these receptors are deeply related to neurodegeneration and inflammation. The analysis was focused on genes related to inflammation and REDOX homeostasis. It was detected that in the three conditions (microglia treated with 2-Cl-IB-MECA, SCH 582561, and their combination) more than 40 % of the detected genes codified by the mitochondrial genome were differentially expressed (FDR < 0.05) (14/34, 16/34, and 13/34) respectively, being almost all of them (>85 %) upregulated in the microglia treated with adenosinergic compounds. Also, we analyzed the differential expression of genes related to mitochondrial function and oxidative stress codified by the nuclear genome. Additionally, we evaluated the oxygen consumption rate (OCR) of mitochondria in microglia treated with LPS and IFN-γ, both alone and in combination with adenosinergic compounds. The data showed an improvement in mitochondrial function with the antagonist of the adenosine A2A receptor, compared to the effects of pro-inflammatory stimulus, confirming a functional effect consistent with the RNAseq data.

Uso de ileostomía derivativa en cáncer de ovario. Revisión de la literatura / Use of diverting ileostomy in ovarian cancer. Literature review

Introducción. La ileostomía derivativa de protección se realiza con el objetivo de proteger la anastomosis intestinal después de una resección colorrectal. Esta resección intestinal es el procedimiento extendido más frecuentemente realizado en pacientes con cáncer de ovario, con el fin de lograr una citorreducción completa. Conocer las indicaciones, el uso, las técnicas y las complicaciones de las ileostomías es importante para los grupos multidisciplinarios que tratan estas pacientes. Métodos. Se realizó una búsqueda en PubMed vía Medline y una revisión narrativa actualizada de los principales hallazgos sobre las indicaciones, las técnicas quirúrgicas, complicaciones y el uso de la ileostomía derivativa en el cáncer de ovario. Resultados. El uso de la ileostomía derivativa en cáncer de ovario sigue siendo un tema controvertido. Hasta la fecha, ni la ileostomía de derivación ni la ileostomía fantasma se han asociado con una reducción en la incidencia de la fuga anastomótica, pero ambas técnicas podrían disminuir su gravedad. Conclusión. La ileostomía de derivación en cáncer de ovario se usa para proteger una anastomosis distal tras una resección intestinal, en caso de fuga anastomótica si no se ha realizado una ostomía previa o en caso de obstrucción intestinal.

Introduction. Protective diverting ileostomy is performed with the aim of protecting the intestinal anastomosis after a colorectal resection. This intestinal resection is the most frequently performed extended procedure in patients with ovarian cancer, in order to achieve complete cytoreduction. Knowing the indications, use, techniques and complications of ileostomies is important for multidisciplinary groups that treat these patients. Methods. We conducted a search in PubMed via Medline and an updated narrative review of the main findings on the indications, surgical techniques, complications and use of diverting ileostomy in ovarian cancer. Results. The use of diverting ileostomy in ovarian cancer remains a controversial issue. To date, neither diverting ileostomy nor ghost ileostomy have been associated with a reduction in the incidence of anastomotic leak, but both techniques could decrease its severity. Conclusion. The diverting ileostomy in ovarian cancer is used to protect a distal anastomosis after intestinal resection, in case of anastomotic leak if a previous ostomy has not been performed or in case of intestinal obstruction.

Membrane Heteroreceptor Complexes as Second-Order Protein Modulators: A Novel Integrative Mechanism through Allosteric Receptor-Receptor Interactions.

Bioluminescence and fluorescence resonance energy transfer (BRET and FRET) together with the proximity ligation method revealed the existence of G-protein-coupled receptors, Ionotropic and Receptor tyrosine kinase heterocomplexes, e.g., A2AR-D2R, GABAA-D5R, and FGFR1-5-HT1AR heterocomplexes. Molecular integration takes place through allosteric receptor-receptor interactions in heteroreceptor complexes of synaptic and extra-synaptic regions. It involves the modulation of receptor protomer recognition, signaling and trafficking, as well as the modulation of behavioral responses. Allosteric receptor-receptor interactions in hetero-complexes give rise to concepts like meta-modulation and protein modulation. The introduction of receptor-receptor interactions was the origin of the concept of meta-modulation provided by Katz and Edwards in 1999, which stood for the fine-tuning or modulation of nerve cell transmission. In 2000-2010, Ribeiro and Sebastiao, based on a series of papers, provided strong support for their view that adenosine can meta-modulate (fine-tune) synaptic transmission through adenosine receptors. However, another term should also be considered: protein modulation, which is the key feature of allosteric receptor-receptor interactions leading to learning and consolidation by novel adapter proteins to memory. Finally, it must be underlined that allosteric receptor-receptor interactions and their involvement both in brain disease and its treatment are of high interest. Their pathophysiological relevance has been obtained, especially for major depressive disorder, cocaine use disorder, and Parkinson's disease.

Heteromers Formed by GPR55 and Either Cannabinoid CB1 or CB2 Receptors Are Upregulated in the Prefrontal Cortex of Multiple Sclerosis Patients.

Multiple sclerosis (MS) is an autoimmune, inflammatory, and neurodegenerative disease of the central nervous system for which there is no cure, making it necessary to search for new treatments. The endocannabinoid system (ECS) plays a very important neuromodulatory role in the CNS. In recent years, the formation of heteromers containing cannabinoid receptors and their up/downregulation in some neurodegenerative diseases have been demonstrated. Despite the beneficial effects shown by some phytocannabinoids in MS, the role of the ECS in its pathophysiology is unknown. The main objective of this work was to identify heteromers of cell surface proteins receptive to cannabinoids, namely GPR55, CB1 and CB2 receptors, in brain samples from control subjects and MS patients, as well as determining their cellular localization, using In Situ Proximity Ligation Assays and immunohistochemical techniques. For the first time, CB1R-GPR55 and CB2R-GPR55 heteromers are identified in the prefrontal cortex of the human brain, more in the grey than in the white matter. Remarkably, the number of CB1R-GPR55 and CB2R-GPR55 complexes was found to be increased in MS patient samples. The results obtained open a promising avenue of research on the use of these receptor complexes as potential therapeutic targets for the disease.

The Olfactory Trail of Neurodegenerative Diseases.

Alterations in olfactory functions are proposed as possible early biomarkers of neurodegenerative diseases. Parkinson's and Alzheimer's diseases manifest olfactory dysfunction as a symptom, which is worth mentioning. The alterations do not occur in all patients, but they can serve to rule out neurodegenerative pathologies that are not associated with small deficits. Several prevalent neurodegenerative conditions, including impaired smell, arise in the early stages of Parkinson's and Alzheimer's diseases, presenting an attractive prospect as a snitch for early diagnosis. This review covers the current knowledge on the link between olfactory deficits and Parkinson's and Alzheimer's diseases. The review also covers the emergence of olfactory receptors as actors in the pathophysiology of these diseases. Olfactory receptors are not exclusively expressed in olfactory sensory neurons. Olfactory receptors are widespread in the human body; they are expressed, among others, in the testicles, lungs, intestines, kidneys, skin, heart, and blood cells. Although information on these ectopically expressed olfactory receptors is limited, they appear to be involved in cell recognition, migration, proliferation, wound healing, apoptosis, and exocytosis. Regarding expression in non-chemosensory regions of the central nervous system (CNS), future research should address the role, in both the glia and neurons, of olfactory receptors. Here, we review the limited but relevant information on the altered expression of olfactory receptor genes in Parkinson's and Alzheimer's diseases. By unraveling how olfactory receptor activation is involved in neurodegeneration and identifying links between olfactory structures and neuronal death, valuable information could be gained for early diagnosis and intervention strategies in neurodegenerative diseases.

Adenosine receptors are the on-and-off switch of astrocytic cannabinoid type 1 (CB1) receptor effect upon synaptic plasticity in the medial prefrontal cortex.

The medial prefrontal cortex (mPFC) is involved in cognitive functions such as working memory. Astrocytic cannabinoid type 1 receptor (CB1R) induces cytosolic calcium (Ca2+) concentration changes with an impact on neuronal function. mPFC astrocytes also express adenosine A1 and A2A receptors (A1R, A2AR), being unknown the crosstalk between CB1R and adenosine receptors in these cells. We show here that a further level of regulation of astrocyte Ca2+ signaling occurs through CB1R-A2AR or CB1R-A1R heteromers that ultimately impact mPFC synaptic plasticity. CB1R-mediated Ca2+ transients increased and decreased when A1R and A2AR were activated, respectively, unveiling adenosine receptors as modulators of astrocytic CB1R. CB1R activation leads to an enhancement of long-term potentiation (LTP) in the mPFC, under the control of A1R but not of A2AR. Notably, in IP3R2KO mice, that do not show astrocytic Ca2+ level elevations, CB1R activation decreases LTP, which is not modified by A1R or A2AR. The present work suggests that CB1R has a homeostatic role on mPFC LTP, under the control of A1R, probably due to physical crosstalk between these receptors in astrocytes that ultimately alters CB1R Ca2+ signaling.

Advancing Personalized Medicine by Analytical Means: Selection of Three Metabolites That Allows Discrimination between Glaucoma, Diabetes, and Controls.

This paper aimed at devising an intelligence-based method to select compounds that can distinguish between open-angle glaucoma patients, type 2 diabetes patients, and healthy controls. Taking the concentration of 188 compounds measured in the aqueous humour (AH) of patients and controls, linear discriminant analysis (LDA) was used to identify the right combination of compounds that could lead to accurate diagnosis. All possibilities, using the leave-one-out approach, were considered through ad hoc programming and in silico massive data production and statistical analysis. Our proof of concept led to the selection of four molecules: acetyl-ornithine (Ac-Orn), C3 acyl-carnitine (C3), diacyl C42:6 phosphatidylcholine (PC aa C42:6), and C3-DC (C4-OH) acyl-carnitine (C3-DC (C4-OH)) that, taken in combination, would lead to a 95% discriminative success. 100% success was obtained with a non-linear combination of the concentration of three of these four compounds. By discarding younger controls to adjust by age, results were similar although one control was misclassified as a diabetes patient. Methods based on the consideration of individual clinical chemical parameters have limitations in the ability to make a reliable diagnosis, stratify patients, and assess disease progression. Leveraging human AH metabolomic data, we developed a procedure that selects a minimal number of metabolites (3-5) and designs algorithms that maximize the overall accuracy evaluating both positive predictive (PPV) and negative predictive (NPV) values. Our approach of simultaneously considering the levels of a few metabolites can be extended to any other body fluid and has potential to advance precision medicine. Artificial intelligence is expected to use algorithms that use the concentration of three to five molecules to correctly diagnose diseases, also allowing stratification of patients and evaluation of disease progression. In addition, this significant advance shifts focus from a single-molecule biomarker approach to that of an appropriate combination of metabolites.

Fluorescent Tools for the Imaging of Dopamine D2 -Like Receptors.

The family of dopamine D2 -like receptors represents an interesting target for a variety of neurological diseases, e. g. Parkinson's disease (PD), addiction, or schizophrenia. In this study we describe the synthesis of a new set of fluorescent ligands as tools for visualization of dopamine D2 -like receptors. Pharmacological characterization in radioligand binding studies identified UR-MN212 (20) as a high-affinity ligand for D2 -like receptors (pKi (D2long R)=8.24, pKi (D3 R)=8.58, pKi (D4 R)=7.78) with decent selectivity towards D1 -like receptors. Compound 20 is a neutral antagonist in a Go1 activation assay at the D2long R, D3 R, and D4 R, which is an important feature for studies using whole cells. The neutral antagonist 20, equipped with a 5-TAMRA dye, displayed rapid association to the D2long R in binding studies using confocal microscopy demonstrating its suitability for fluorescence microscopy. Furthermore, in molecular brightness studies, the ligand's binding affinity could be determined in a single-digit nanomolar range that was in good agreement with radioligand binding data. Therefore, the fluorescent compound can be used for quantitative characterization of native D2 -like receptors in a broad variety of experimental setups.

Shedding Light on the D1 -Like Receptors: A Fluorescence-Based Toolbox for Visualization of the D1 and D5 Receptors.

Dopamine D1 -like receptors are the most abundant type of dopamine receptors in the central nervous system and, even after decades of discovery, still highly interesting for the study of neurological diseases. We herein describe the synthesis of a new set of fluorescent ligands, structurally derived from D1 R antagonist SCH-23390 and labeled with two different fluorescent dyes, as tool compounds for the visualization of D1 -like receptors. Pharmacological characterization in radioligand binding studies identified UR-NR435 (25) as a high-affinity ligand for D1 -like receptors (pKi (D1 R)=8.34, pKi (D5 R)=7.62) with excellent selectivity towards D2 -like receptors. Compound 25 proved to be a neutral antagonist at the D1 R and D5 R in a Gs heterotrimer dissociation assay, an important feature to avoid receptor internalization and degradation when working with whole cells. The neutral antagonist 25 displayed rapid association and complete dissociation to the D1 R in kinetic binding studies using confocal microscopy verifying its applicability for fluorescence microscopy. Moreover, molecular brightness studies determined a single-digit nanomolar binding affinity of the ligand, which was in good agreement with radioligand binding data. For this reason, this fluorescent ligand is a useful tool for a sophisticated characterization of native D1 receptors in a variety of experimental setups.

A metabolomics study in aqueous humor discloses altered arginine metabolism in Parkinson's disease.

BACKGROUND: The lack of accessible and informative biomarkers results in a delayed diagnosis of Parkinson's disease (PD), whose symptoms appear when a significant number of dopaminergic neurons have already disappeared. The retina, a historically overlooked part of the central nervous system (CNS), has gained recent attention. It has been discovered that the composition of cerebrospinal fluid influences the aqueous humor composition through microfluidic circulation. In addition, alterations found in the brain of patients with PD have a correlate in the retina. This new paradigm highlights the potential of the aqueous humor as a sample for identifying differentially concentrated metabolites that could, eventually, become biomarkers if also found altered in blood or CSF of patients. In this research we aim at analyzing the composition of the aqueous humor from healthy controls and PD patients. METHODS: A targeted metabolomics approach with concentration determination by mass spectrometry was used. Statistical methods including principal component analysis and linear discriminants were used to select differentially concentrated metabolites that allow distinguishing patients from controls. RESULTS: In this first metabolomics study in the aqueous humor of PD patients, elevated levels of 16 compounds were found; molecules differentially concentrated grouped into biogenic amines, amino acids, and acylcarnitines. A biogenic amine, putrescine, alone could be a metabolite capable of differentiating between PD and control samples. The altered levels of the metabolites were correlated, suggesting that the elevations stem from a common mechanism involving arginine metabolism. CONCLUSIONS: A combination of three metabolites, putrescine, tyrosine, and carnitine was able to correctly classify healthy participants from PD patients. Altered metabolite levels suggest altered arginine metabolism. The pattern of metabolomic disturbances was not due to the levodopa-based dopamine replacement medication because one of the patients was not yet taking levodopa but a dopamine receptor agonist.

Cannabidiol at Nanomolar Concentrations Negatively Affects Signaling through the Adenosine A2A Receptor.

Cannabidiol (CBD) is a phytocannabinoid with potential as a therapy for a variety of diseases. CBD may act via cannabinoid receptors but also via other G-protein-coupled receptors (GPCRs), including the adenosine A2A receptor. Homogenous binding and signaling assays in Chinese hamster ovary (CHO) cells expressing the human version of the A2A receptor were performed to address the effect of CBD on receptor functionality. CBD was not able to compete for the binding of a SCH 442416 derivative labeled with a red emitting fluorescent probe that is a selective antagonist that binds to the orthosteric site of the receptor. However, CBD reduced the effect of the selective A2A receptor agonist, CGS 21680, on Gs-coupling and on the activation of the mitogen activated kinase signaling pathway. It is suggested that CBD is a negative allosteric modulator of the A2A receptor.

Boolean analysis shows a high proportion of dopamine D2 receptors interacting with adenosine A2A receptors in striatal medium spiny neurons of mouse and non-human primate models of Parkinson's disease.

The antagonistic effect of adenosine on dopaminergic transmission in the basal ganglia indirect motor control pathway is mediated by dopamine D2 (D2R) and adenosine A2A (A2AR) receptors co-expressed on medium spiny striatal neurons. The pathway is unbalanced in Parkinson's disease (PD) and an A2AR blocker has been approved for use with levodopa in the therapy of the disease. However, it is not known whether the therapy is acting on individually expressed receptors or in receptors forming A2A-D2 receptor heteromers, whose functionality is unique. For two proteins prone to interact, a very recently developed technique, MolBoolean, allows to determine the number of proteins that are either non-interacting or interacting. After checking the feasibility of the technique and reliability of data in transfected cells and in striatal primary neurons, the Boolean analysis of receptors in the striatum of rats and monkeys showed a high percentage of D2 receptors interacting with the adenosine receptor, while, on the contrary, a significant proportion of A2A receptors do not interact with dopamine receptors. The number of interacting receptors increased when rats and monkeys were lesioned to become a PD model. The use of a tracer of the indirect pathway in monkeys confirmed that the data was restricted to the population of striatal neurons projecting to the GPe. The results are not only relevant for being the first study quantifying individual versus interacting G protein-coupled receptors, but also for showing that the D2R in these specific neurons, in both control and PD animals, is under the control of the A2AR. The tight adenosine/dopamine receptor coupling suggest benefits of early antiparkinsonian treatment with adenosine receptor blockers.

Uterine collision tumor. Case report and review of the literature / Tumor de colisión de útero. Reporte de caso y revisión de la literatura

Objectives: To report the case of a patient with a uterine collision tumor and to conduct a review of the literature. Material and methods: A 76-year-old patient who presented to the national cancer referral center in Bogota (Colombia), where she was diagnosed with a uterine collision tumor consisting of a seroustype endometrial adenocarcinoma and a cervical adenosarcoma. The patient underwent surgical treatment followed by chemotherapy and supplemental radiotherapy, and died 16 months later. A search was conducted in the Medline via PubMed and Embase databases, including reports and case series of women with a diagnosis of uterine collision tumor, with retrieval of information regarding diagnosis, treatment and prognosis. A narrative summary of the findings was made. Results: The search identified 36 titles, of which 14 studies with 17 patients were included. The most frequent histopathological diagnosis was endometrial adenocarcinoma and high and low grade endometrial sarcoma (47 %). Primary treatment was surgery and adjuvant treatment with chemotherapy and radiotherapy (15 %) was performed in close to 50 % of cases. One-year survival was 75 %. Conclusions: No cases of uterine collision tumors with the histopathology or in the location of the reported case were found in the literature. If this reported case is taken into account, 2-year mortality is 28 %. Further studies to describe the immunohistochemistry, treatment and prognosis of this condition are needed.

Objetivos: reportar el caso de una paciente con tumor de colisión del útero y realizar una revisión de la literatura respecto al diagnóstico histopatológico, tratamiento y pronóstico de esta condición. Materiales y métodos: mujer de 76 años que consultó al centro nacional de referencia del cáncer en Bogotá (Colombia), donde se hizo el diagnóstico de tumor de colisión del útero, compuesto por un adenocarcinoma de endometrio tipo seroso y adenosarcoma de cérvix. Recibió tratamiento quirúrgico más quimioterapia y radioterapia complementaria, falleció a los 16 meses. Se realizó una búsqueda de la literatura en las bases de datos Medline vía PubMed y Embase, que incluía reportes y series de caso de mujeres con diagnóstico de tumor de colisión del útero, y se extrajo información sobre el diagnóstico, tratamiento y pronóstico. Se realizó un resumen narrativo de los hallazgos. Resultados: la búsqueda identificó 36 títulos, de los cuales se incluyeron 14 estudios que incluían 17 pacientes. El diagnóstico histopatológico más frecuente fue el adenocarcinoma endometrioide de endometrio y sarcoma endometrial de alto y bajo grado (47 %). El tratamiento básico fue quirúrgico. Cerca del 50 % recibió tratamiento adyuvante con quimioterapia y radioterapia (15 %). La sobrevida a 1 año fue del 75 %. Conclusiones: en la literatura no se identificaron casos de tumores de colisión de útero con la histopatología y en la ubicación del caso presentado. La mortalidad a dos años es cercana al 28 % si se toma en cuenta el caso reportado. Se necesitan más estudios que describan la inmunohistoquímica, el tratamiento y el pronóstico de esta condición.

The NADPH Link between the Renin Angiotensin System and the Antioxidant Mechanisms in Dopaminergic Neurons.

The renin angiotensin system (RAS) has several components including signaling peptides, enzymes, and membrane receptors. The effort in characterizing this system in the periphery has led to the approval of a class of antihypertensives. Much less is known about RAS in the central nervous system. The production of RAS peptides and the expression of several RAS enzymes and receptors in dopaminergic neurons of the substantia nigra has raised expectations in the therapy of Parkinson's disease, a neurodegenerative condition characterized by lack of dopamine in the striatum, the motor control region of the mammalian brain. On the one hand, dopamine production requires reducing power. On the other hand, reducing power is required by mechanisms involved in REDOX homeostasis. This review focuses on the potential role of RAS in the regulation of neuronal/glial expression of glucose-6-phosphate dehydrogenase, which produces the NADPH required for dopamine synthesis and for reactive oxygen species (ROS) detoxification. It is known that transgenic expression of the gene coding for glucose-6-phosphate dehydrogenase prevents the death of dopaminergic nigral neurons. Signaling via angiotensin II G protein-coupled receptors, AT1 or AT2, leads to the activation of protein kinase A and/or protein kinase C that in turn can regulate glucose-6- phosphate dehydrogenase activity, by Ser/Thr phosphorylation/dephosphorylation events. Long-term effects of AT1 or AT2 receptor activation may also impact on the concentration of the enzyme via activation of transcription factors that participate in the regulation of gene expression in neurons (or glia). Future research is needed to determine how the system can be pharmacologically manipulated to increase the availability of NADPH to neurons degenerating in Parkinson's disease and to neuroprotective glia.

Signal Amplification for Cell-Free Biosensors, an Analog-to-Digital Converter.

Toehold switches are biosensors useful for the detection of endogenous and environmental RNAs. They have been successfully engineered to detect virus RNAs in cell-free gene expression reactions. Their inherent sequence programmability makes engineering a fast and predictable process. Despite improvements in the design, toehold switches suffer from leaky translation in the OFF state, which compromises the fold change and sensitivity of the biosensor. To address this, we constructed and tested signal amplification circuits for three toehold switches triggered by Dengue and SARS-CoV-2 RNAs and an artificial RNA. The serine integrase circuit efficiently contained leakage, boosted the expression fold change from OFF to ON, and decreased the detection limit of the switches by 3-4 orders of magnitude. Ultimately, the integrase circuit converted the analog switches' signals into digital-like output. The circuit is broadly useful for biosensors and eliminates the hard work of designing and testing multiple switches to find the best possible performer.