Implication of GluR2 subunit of AMPA receptor in RGS14(414)-mediated memory enhancement

Ongoing quest for finding treatment against memory loss seen in aging and in many neurological and neurodegenerative diseases, so far has been unsuccessful and memory enhancers are seen as a potential remedy against this brain dysfunction. Recently, we showed that gene corresponding to a protein called regulator of G-protein signaling 14 of 414 amino acids (RGS14414) is a robust memory enhancer (Lopez-Aranda et al. 2009: Science). RGS14414-treatment in area V2 of visual cortex caused memory enhancement to such extent that it converted short-term object recognition memory (ORM) of 45min into long lasting long-term memory that could be traced even after many months. Now, through targeting of multiple receptors and molecules known to be involved in memory processing, we found that GluR2 subunit of AMPA receptor might be key to memory enhancement in RGS-animals. RGS14-animals showed a progressive increase in GluR2 protein expression while processing an object information which reached to highest level after 60min of object exposure, a time period required for conversion of short-term ORM into long-term memory in our laboratory set up. Normal rats could retain an object information in brain for 45min (short-term) and not for 60min. However, RGS-treated rats are able to retain the same information for 24h or longer (long-term). Therefore, highest expression of GluR2 subunit seen at 60min suggests that this protein might be key in memory enhancement and conversion to long-term memory in RGS-animals. In addition, we will also discuss the implication of Hebbian plasticity and interaction of brain circuits in memory enhancement.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. This work was supported by project BFU2013-43458-R from MINECO, P12-CTS-1694 from JA

Role of RGS14(414) in object recognition memory and regulation of synaptic plasticity in perirhinal cortex

Participation of perirhinal and frontal cortices in processing of object recognition memory has long been recognized, however, recently our laboratory extended this to area V2 of visual cortex. We observed that RGS14414-mediated activation of area V2 neurons leads to an enormous increase in object recognition memory. This memory enhancement was of such extent that it converted short term memory of 45 minutes into long lasting long-term memory that could be traced even after many months. Here, we have tested the memory enhancer effect of RGS14414 in perirhinal cortex, an area intimately involved in processing of object memory. A relationship of behavioral performance of RGS14414-treated rats with electrophysiological synaptic plasticity was investigated. Stimulation of perirhinal cortex with RGS14414 produced an equally robust increase in object recognition memory as was observed in area V2. Further, we found that RGS14414-mediated activation of perirhinal cortex, (i) blocked the depotentiation induced by 1Hz stimulation during 10min; (ii) blocked the LTP induced by 20Hz stimulation while showed no effect at 100Hz stimulation; and (iii) reduced the LTD induced by the application of 20µM carbachol, a cholinergic receptor agonist, during 10min, however no effect was observed at a higher concentration (50µM). Furthermore, we also observed that phosphorylated isoforms of AMPA receptor 1 and 2 (iGluR1 & iGluR2) were significantly reduced. Thus, our results indicate that iGluRs reflects the level of synaptic plasticity (LTP and LTD) observed in RGS-animals but lack this correlation with enhanced memory behavior. This work was supported by projects from MINECO, Junta de Andalucía y NIH.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

A clinically compatible drug-screening platform based on organotypic cultures identifies vulnerabilities to prevent and treat brain metastasis

We report a medium-throughput drug-screening platform (METPlatform) based on organotypic cultures that allows to evaluate inhibitors against metastases growing in situ. By applying this approach to the unmet clinical need of brain metastasis, we identified several vulnerabilities. Among them, a blood-brain barrier permeable HSP90 inhibitor showed high potency against mouse and human brain metastases at clinically relevant stages of the disease, including a novel model of local relapse after neurosurgery. Furthermore, in situ proteomic analysis applied to metastases treated with the chaperone inhibitor uncovered a novel molecular program in brain metastasis, which includes biomarkers of poor prognosis and actionable mechanisms of resistance. Our work validates METPlatform as a potent resource for metastasis research integrating drug-screening and unbiased omic approaches that is compatible with human samples. Thus, this clinically relevant strategy is aimed to personalize the management of metastatic disease in the brain and elsewhere.Acknowledgments: This work was supported by MINECO (SAF2017-89643-R, SAF2014-57243-R, SAF2015-62547-ERC) (M.V.), Fundacion FERO (IX FERO Grant for Research in Oncology) (M.V.), Fundacio La Marato de TV3 (141) (M.V.), Melanoma Research Alliance (Bristol-Myers Squibb-Melanoma Research Alliance Young Investigator Award 2017 (https://doi.org/10.48050/pc.gr.75716)) (M.V.), Beug Foundation (Prize for Metastasis Research 2017) (M.V.), Fundacion Ramon Areces (CIVP19S8163) (M.V.) and CIVP20S10662 (E.O.P.), Worldwide Cancer Research (19-0177) (M.V.), H2020-FETOPEN (828972) (M.V.), Cancer Research Institute (Clinic and Laboratory Integration Program CRI Award 2018 (54545)) (M.V.), AECC (Coordinated Translational Groups 2017 (GCTRA16015SEOA) (M.V.), LAB AECC 2019 (LABAE19002-VALI) (M.V.), ERC CoG (864759) (M.V.), Sophien-Stiftung zur Förderung der klinischen Krebsforschung (T.W.), Promedica Stiftung (T.W.), Stiftung f€ur angewandte Krebsforschung (T.W.), Forschungskredit of the University of Zurich (FK-18-054) (T.W.), Betty and David Koetser Foundation for Brain Research (T.W.), Foundation for Applied Cancer Research in Zurich (T.W., M.W.), Comunidad de Madrid (S2017/BMD-3867 RENIM-CM and Y2018/NMT-4949 NanoLiver-CM) and European structural and investment funds (M.D.), ISCIII (PT20/00044) co-funded by FEDER “A way of making Europe” (M.D.), Ministero dell’Istruzione, dell’Universita e della Ricerca-MIUR, “Dipartimenti di Eccellenza 2018-2022”, (D15D18000410001) (L.B. and P.C.), Science Foundation Ireland Frontiers for the Future Award (19/FFP/6443) (L.Y.), Science Foundation Ireland Strategic Partnership Programme, Precision Oncology Ireland (18/SPP/3522) (L.Y.), Breast Cancer Now Fellowship Award/ with the generous support of Walk the Walk (2019AugSF1310) (D.V.), La Caixa-Severo Ochoa International PhD Program Fellowship (LCF/BQ/SO16/52270014) (L.Z.), La Caixa International PhD Program Fellowship-Marie Sklodowska-Curie (LCF/BQ/DI17/11620028) (P.G-G), MINECO-Severo Ochoa PhD Fellowship (BES-2017-081995) (L.A-E.), AECC Postdoctoral Fellowship (POSTD19016PRIE) (N.P.), Boehringer Ingelheim Fonds MD fellowship (L.M.). The contribution of the Experimental Therapeutics Programme was supported by core funding from the Spanish National Cancer Research Center (CNIO). CNIO is supported by the ISCIII, the Ministerio de Ciencia e Innovacion, and is a Severo Ochoa Center of Excellence (SEV-2015-0510). The CNIC is supported by the ISCIII, the Ministerio de Ciencia e Innovacion and the Pro CNIC Foundation, and is a Severo Ochoa Center of Excellence (SEV-2015-0505). M.V. was named Ramon y Cajal Investigator (RYC-2013-13365) and is member of EMBO YIP (4053)

A clinically compatible drug-screening platform based on organotypic cultures identifies vulnerabilities to prevent and treat brain metastasis

We report a medium‐throughput drug‐screening platform (METPlatform) based on organotypic cultures that allows to evaluate inhibitors against metastases growing in situ. By applying this approach to the unmet clinical need of brain metastasis, we identified several vulnerabilities. Among them, a blood–brain barrier permeable HSP90 inhibitor showed high potency against mouse and human brain metastases at clinically relevant stages of the disease, including a novel model of local relapse after neurosurgery. Furthermore, in situ proteomic analysis applied to metastases treated with the chaperone inhibitor uncovered a novel molecular program in brain metastasis, which includes biomarkers of poor prognosis and actionable mechanisms of resistance. Our work validates METPlatform as a potent resource for metastasis research integrating drug‐screening and unbiased omic approaches that is compatible with human samples. Thus, this clinically relevant strategy is aimed to personalize the management of metastatic disease in the brain and elsewhere

A mechanism of RGS14(414)-mediated recovery of an episodic memory loss: implication of GluR2 subunit of AMPA receptor

Background and objectives: The ongoing quest for finding treatment against memory loss seen in aging and in many neurological and neurodegenerative diseases, so far has been unsuccessful and more effective and precise therapeutic strategies are needed. The study of memory enhancement seems to hold the potential for developing strategies to treat memory dysfunctions. In line to this, previously, we have shown that the delivery of RGS14(414) gene into V2 visual cortex of rodent’s brain enhanced object recognition memory, which is one of the most studied examples of episodic memory. This memory enhancement effect was of such extent that it converted short term memory of 45 minutes into long lasting long-term memory that could be traced even after many months. Therefore, we have tested first whether object recognition memory loss observed in normal aging and Alzheimer´s disease can be recuperated by the same RGS14(414) gene treatment. Further, we explored through various biological processes in brain to provide explanation of RGS14-mediated memory enhancement and recuperation of memory loss. -Results and discussion: In the present thesis work we found that: (i) RGS14(414) gene treatment not only led to full recovery of an episodic memory loss in rodent models of normal aging and Alzheimer´s disease, but also aided in maintenance of the elevated ORM levels for long time; (ii) GluR2, an AMPA receptor subunit, showed upregulated level as well as a dynamic participation in conversion of short-term ORM into long-term memory in RGS14 rats; (iii) Area V2, frontal cortex and perirhinal cortex, areas that participate in brain circuit responsible for ORM processing, are not dependent on each other in RGS14-mediated memory enhancement; This independency of these brain areas in memory enhancement suggests that they are individually adequate for treatment of memory loss, in spite of where the primary cause is localized in brain; (iiii) RGS14(414) gene treatment did not favor Hebbian synaptic plasticity, which included LTP, muscarinic receptor-dependent LTD, and depotentiation. Though underlying cause of this lack in plasticity is yet to be elucidated, we believe that a decrease in calcium influx through RGS14-mediated blockage of L-type calcium channel could trigger the impairments seen in Hebbian plasticity, and that RGS14-mediated ORM enhancement could be reliant on non-Hebbian forms of plasticity. -Conclusions: On one hand, the proteomic results showed that GluR2 subunit is a key in RGS14-mediated ORM enhancement. On the other hand, the behavioral results of memory loss recovery in rodent models and of memory enhancement in lesioned rats demonstrate that RGS14(414) gene therapy might be a viable strategy for the treatment of memory loss in patients

Machine learning identifies experimental brain metastasis subtypes based on their influence on neural circuits

A high percentage of patients with brain metastases frequently develop neurocognitive symptoms; however, understanding how brain metastasis co-opts the function of neuronal circuits beyond a tumor mass effect remains unknown. We report a comprehensive multidimensional modeling of brain functional analyses in the context of brain metastasis. By testing different preclinical models of brain metastasis from various primary sources and oncogenic profiles, we dissociated the heterogeneous impact on local field potential oscillatory activity from cortical and hippocampal areas that we detected from the homogeneous inter-model tumor size or glial response. In contrast, we report a potential underlying molecular program responsible for impairing neuronal crosstalk by scoring the transcriptomic and mutational profiles in a model-specific manner. Additionally, measurement of various brain activity readouts matched with machine learning strategies confirmed model-specific alterations that could help predict the presence and subtype of metastasi

RGS14414 treatment induces memory enhancement and rescues episodic memory deficits.

Memory deficits affect a large proportion of the human population and are associated with aging and many neurologic, neurodegenerative, and psychiatric diseases. Treatment of this mental disorder has been disappointing because all potential candidates studied thus far have failed to produce consistent effects across various types of memory and have shown limited to no effects on memory deficits. Here, we show that the promotion of neuronal arborization through the expression of the regulator of G-protein signaling 14 of 414 amino acids (RGS14414) not only induced robust enhancement of multiple types of memory but was also sufficient for the recovery of recognition, spatial, and temporal memory, which are kinds of episodic memory that are primarily affected in patients or individuals with memory dysfunction. We observed that a surge in neuronal arborization was mediated by up-regulation of brain-derived neurotrophic factor (BDNF) signaling and that the deletion of BDNF abrogated both neuronal arborization activation and memory enhancement. The activation of BDNF-dependent neuronal arborization generated almost 2-fold increases in synapse numbers in dendrites of pyramidal neurons and in neurites of nonpyramidal neurons. This increase in synaptic connections might have evoked reorganization within neuronal circuits and eventually supported an increase in the activity of such circuits. Thus, in addition to showing the potential of RGS14414 for rescuing memory deficits, our results suggest that a boost in circuit activity could facilitate memory enhancement and the reversal of memory deficits.-Masmudi-Martín, M., Navarro-Lobato, I., López-Aranda, M. F., Delgado, G., Martín-Montañez, E., Quiros-Ortega, M. E., Carretero-Rey, M., Narváez, L., Garcia-Garrido, M. F., Posadas, S., López-Téllez, J. F., Blanco, E., Jiménez-Recuerda, I., Granados-Durán, P., Paez-Rueda, J., López, J. C., Khan, Z. U. RGS14414 treatment induces memory enhancement and rescues episodic memory deficits