Adrenergic Modulation With Photochromic Ligands

© 2020 Wiley-VCH GmbH Adrenoceptors are ubiquitous and mediate important autonomic functions as well as modulating arousal, cognition, and pain on a central level. Understanding these physiological processes and their underlying neural circuits requires manipulating adrenergic neurotransmission with high spatio-temporal precision. Here we present a first generation of photochromic ligands (adrenoswitches) obtained via azologization of a class of cyclic amidines related to the known ligand clonidine. Their pharmacology, photochromism, bioavailability, and lack of toxicity allow for broad biological applications, as demonstrated by controlling locomotion in zebrafish and pupillary responses in mice

Therapeutic targeting of HER2–CB2R heteromers in HER2-positive breast cancer

There is a subtype of breast cancer characterized by the overexpression of the oncogene HER2. Although most patients with this diagnosis benefit from HER2-targeted treatments, some do not respond to these therapies and others develop resistance with time. New tools are therefore warranted for the treatment of this patient population, and for early identification of those individuals at a higher risk of developing innate or acquired resistance to current treatments. Here, we show that HER2 forms heteromer complexes with the cannabinoid receptor CB2R, the expression of these structures correlates with poor patient prognosis, and their disruption promotes antitumor responses. Collectively, our results support HER2–CB2R heteromers as new therapeutic targets and prognostic tools in HER2+ breast cancer

Activation of the orphan receptor GPR55 by lysophosphatidylinositol promotes metastasis in triple-negative breast cancer

The orphan G protein-coupled receptor GPR55 has been directly or indirectly related to basic alterations that drive malignant growth: uncontrolled cancer cell proliferation, sustained angiogenesis, and cancer cell adhesion and migration. However, little is known about the involvement of this receptor in metastasis. Here, we show that elevated GPR55 expression in human tumors is associated with the aggressive basal/triple-negative breast cancer population, higher probability to develop metastases, and therefore poor patient prognosis. Activation of GPR55 by its proposed endogenous ligand lysophosphatidylinositol confers pro-invasive features on breast cancer cells both in vitro and in vivo. Specifically, this effect is elicited by coupling to Gq/11 heterotrimeric proteins and the subsequent activation, through ERK, of the transcription factor ETV4/PEA3. Together, these data show that GPR55 promotes breast cancer metastasis, and supports the notion that this orphan receptor may constitute a new therapeutic target and potential biomarker in the highly aggressive triple-negative subtypeThis work was supported by grants from Spanish Ministry of Economy and Competitiveness [PI11/00295 to CS, PI14/01101 to CS and EP-G, SAF2013-46183-R to MQ, and SAF2014-54705-R to MV-M, supported with European Regional Development (FEDER) funds] and Madrid Regional Government (S2010/BMD-2308 to MG, and 2010/BMD-2359 to MQ). EPG was a recipient of a Postdoctoral Research Contract from Fundación Científica Asociación Española Contra el Cáncer and a Federation of the Societies of Biochemistry and Molecular Biology (FEBS) Short-term Fellowship. SB-B and SC-L are recipients of a Formación de Profesorado Universitario (FPU) fellowship and a Ramón y Cajal research contract, respectively, from the Spanish Ministry of Economy and Competitivenes

BIASED AGONISM OF THREE DIFFERENT CANNABINOID RECEPTOR AGONISTS IN MOUSE BRAIN CORTEX

Cannabinoid receptors are able to couple to different families of G-proteins when activated by an agonist drug. It has been suggested that different intracellular responses may be activated depending on the ligand. The goal of the present study was to characterize the pattern of G protein subunit stimulation triggered by three different cannabinoid ligands, THC, WIN55212-2 and ACEA in mouse brain cortex.Stimulation of the [35S]GTPS binding coupled to specific immunoprecipitation with antibodies against different subtypes of G proteins (Gαi1, Gαi2, Gαi3, Gαo, Gαz, Gαs, Gαq/11, and Gα12/13), in the presence of Δ9-THC, WIN55212-2 and ACEA (submaximal concentration 10 µM) was determined by Scintillation Proximity Assay (SPA) technique in mouse cortex of wild type, CB1 knock-out, CB2 knock-out and CB1/CB2 double knock-out mice. Results show that, in mouse brain cortex, cannabinoid agonists are able to significantly stimulate not only the classical inhibitory Gαi/o subunits but also other G subunits like Gαz, Gαq/11, and Gα12/13. Moreover, the specific pattern of G protein subunit activation is different depending on the ligand. In conclusion, our results demonstrate that, in mice brain native tissue, different exogenous cannabinoid ligands are able to selectively activate different inhibitory and non-inhibitory Gα protein subtypes, through the activation of CB1 and/or CB2 receptors. Results of the present study may help to understand the specific molecular pathways involved in the pharmacological effects of cannabinoid-derived drugs

Comparison of gene expression patterns in cerebral cortex between three different animal models of depression

Trabajo presentado al XXX Congreso de la Sociedad Española de Farmacología celebrado en Bilbao del 17 al 19 de septiembre de 2008.Animal models involve a unique tool for the study of the pathophysiology of major depression and the evaluation of the therapeutic efficacy of new antidepressant drugs. However, little is known about the gene expression pattern through the brain in these animal models, and their likely resemblance to what happens in humans suffering major depression. The expression level of approximately 30,000 genes was analysed in cerebral cortex samples from three different rat models of depression: model of acute treatment with reserpine (5 mg/kg i.p.), model of olfactory bulbectomy, and model of chronic treatment with corticosterone (18 mg/kg/day, subcutaneously implanted pellet); and compared with that obtained from respective control animals. Expression analysis was carried out with Affymetrix® GeneChip® technology. Results were assessed with Gene Chip Operating Software (GCOS 1.3. Affymetrix®) and analysed using GeneSpring GX v7.3 (Agilent) and dChip bioinformatic software. Detected changes in gene expression were validated by means of quantitative RT-PCR assays. Ontological analysis of the results revealed that genes showing differential expression in three models (n=6-10 animals per group) are involved in neurochemical pathways related with programmed cell death. However, only two of these genes (Fabp7 and C3) showed differential expression level in all three models. Both genes were validated with RTPCR assays. On the other hand, several of the genes classically related to human major depression were studied, although only HTr2a, NTrk3, Crhr1, Ntrk2 and Crh showed expression changes in at least one of the three animal models. These results were not validated with RT-PCR. The results demonstrate that the three models, in spite of showing differences in their gene expression patterns, share modifications in neuronal signalling pathways (apoptosis and cellular differentiation). Some of the genes classically related with depression are also modified in these animal models. These findings suggest that the corticosterone model is the one which most closely resembles the findings in postmortem human brains of depressed subjects.Supported by the Basque Government, Spanish Ministry of Education and Science (SAF 04/02784 and 04/0941) and Instituto de Salud Carlos III (CIBERsam). L.U. is supported by Juan de la Cierva Programme.Peer Reviewe

Effect of antipsychotic drugs on group II metabotropic glutamate receptor expression and epigenetic control in postmortem brains of schizophrenia subjects

Abstract Antipsychotic-induced low availability of group II metabotropic glutamate receptors (including mGlu2R and mGlu3R) in brains of schizophrenia patients may explain the limited efficacy of mGlu2/3R ligands in clinical trials. Studies evaluating mGlu2/3R levels in well-designed, large postmortem brain cohorts are needed to address this issue. Postmortem samples from the dorsolateral prefrontal cortex of 96 schizophrenia subjects and matched controls were collected. Toxicological analyses identified cases who were (AP+) or were not (AP-) receiving antipsychotic treatment near the time of death. Protein and mRNA levels of mGlu2R and mGlu3R, as well as GRM2 and GRM3 promoter-attached histone posttranslational modifications, were quantified. Experimental animal models were used to compare with data obtained in human tissues. Compared to matched controls, schizophrenia cortical samples had lower mGlu2R protein amounts, regardless of antipsychotic medication. Downregulation of mGlu3R was observed in AP- schizophrenia subjects only. Greater predicted occupancy values of dopamine D2 and serotonin 5HT2A receptors correlated with higher density of mGlu3R, but not mGlu2R. Clozapine treatment and maternal immune activation in rodents mimicked the mGlu2R, but not mGlu3R regulation observed in schizophrenia brains. mGlu2R and mGlu3R mRNA levels, and the epigenetic control mechanisms did not parallel the alterations at the protein level, and in some groups correlated inversely. Insufficient cortical availability of mGlu2R and mGlu3R may be associated with schizophrenia. Antipsychotic treatment may normalize mGlu3R, but not mGlu2R protein levels. A model in which epigenetic feedback mechanisms controlling mGlu3R expression are activated to counterbalance mGluR loss of function is described

Adrenergic Modulation with Photochromic Ligands

Adrenoceptors are ubiquitous and regulate heart and respiratory rate, digestion, metabolism, and vascular tone. They can be activated or blocked with adrenergic drugs, but systemic administration causes broad adverse effects. We have developed photochromic ligands (adrenoswitches) to switch on and off adrenoceptor activity on demand at selected locations. Their pharmacology, photochromism, bioavailability and lack of toxicity allow photomodulating adrenergic signalling, as demonstrated by controlling locomotion in zebrafish and pupillary responses in blind mice