Novel Small-RNA Mediated Gene Regulatory Mechanisms for Long-Term Memory

Memory storage and memory-related synaptic plasticity rely on precise spatiotemporal regulation of gene expression. To explore the role of small RNAs in memory-related synaptic plasticity we carried out massive parallel sequencing to profile the small RNAs of Aplysia. We identified 170 distinct 21-23 nt sized miRNAs, 13 of which were novel and specific to Aplysia. Nine miRNAs were brain-enriched, and several of these were rapidly down-regulated by transient exposure to serotonin, a modulatory neurotransmitter released during learning. Two abundant, and conserved brain-specific miRNAs, miR-124 and miR-22 were exclusively present pre-synaptically in a sensory-motor synapse where they constrain synaptic facilitation through regulation of the transcriptional factor CREB1 and translation factor CPEB respectively. We therefore provide the first evidence that a modulatory neurotransmitter important for learning can regulate the levels of small RNAs and present a novel role for miR-124 and miR-22 in long-term plasticity of synapses in the mature nervous system. While mining the small RNA libraries for miRNAs, we discovered an unexpected and abundant expression in brain of a 28-nt sized class of piRNAs, which had been thought to be germ-line specific. These piRNAs have unique biogenesis patterns and predominant nuclear localization. Moreover, we find that whereas miRNAs are down-regulated by exposure to serotonin, piRNAs are up-regulated. Importantly, we find that the piwi/piRNA complex facilitates serotonin-dependent methylation of a conserved CpG island in the promoter of CREB2, the major inhibitory constraint of memory in Aplysia, leading to the persistence of long-term synaptic facilitation. Taken together, these findings provide a new serotonin-dependent, bidirectional, small-RNA mediated gene regulatory mechanism during plasticity where miRNAs provide translational control and piRNAs provide long-lasting transcriptional control for the persistence of memory

Systems modeling: a pathway to drug discovery

Systems modeling is emerging as a valuable tool in therapeutics. This is seen by the increasing use of clinically relevant computational models and a rise in systems biology companies working with the pharmaceutical industry. Systems models have helped understand the effects of pharmacological intervention at receptor, intracellular and intercellular communication stages of cell signaling. For instance, angiogenesis models at the ligand-receptor interaction level have suggested explanations for the failure of therapies for cardiovascular disease. Intracellular models of myeloma signaling have been used to explore alternative drug targets and treatment schedules. Finally, modeling has suggested novel approaches to treating disorders of intercellular communication, such as diabetes. Systems modeling can thus fill an important niche in therapeutics by making drug discovery a faster and more systematic process

Multiplexed Intact-Tissue Transcriptional Analysis at Cellular Resolution

U ovom radu uspoređeno je nekoliko tehničkih rješenja sustava grijanja, hlađenja i pripreme potrošne tople vode za referentnu niskoenergetsku hotelsku zgradu u primorskoj Hrvatskoj prema kriteriju primarne energije, troškova investicije i troškova pogona. Referentna hotelska zgrada se sastoji od 7 etaža i ukupne je podne površine 6.912 m2, potrebnog ogrjevnog učina 260 kW i rashladnog učina 400 kW. Zgrada je podijeljena u tri proračunske zone. Zona broj 1 su sobe, nalazi se na katovima od 2 do 6, prirodno je ventilirana i ima cirkulacijsku petlju potrošne tople vode. Zona broj 2 je kuhinja, nalazi se na prvom katu, ima mehaničku ventilaciju s rekuperatorima i nema cirkulacijsku petlju potrošne tople vode. Zona broj 3 su zajedničke prostorije, nalazi se u prizemlju i na prvom katu, ima mehaničku ventilaciju s rekuperatorima i nema cirkulacijsku petlju potrošne tople vode. Za sve proračunske zone je predviđeni sustav grijanja i hlađenja pomoću ventilokonvektora u dvocijevnoj izvedbi. Za sve proračunske zone je temperaturni režim grijanja je 45/40°C, a hlađenja 7/12°C. Potrebna toplinska energija za grijanje zgrade QH,nd i za hlađenje zgrade QC,nd izračunata je prema HRN EN ISO 13790 mjesečnom i jednostavnom satnom metodom za karakterističan dan u mjesecu te su rezultati međusobno uspoređeni. Proračun sustava za pripremu PTV-a je prema normama HRN EN 15316-3-1, HRN EN 15316-3-2, HRN EN 15316-3-3. Proračun sustava za grijanje i hlađenje prostora je prema normama HRN EN 15316-2-1, HRN EN 15316-2-3, HRN EN 15316-4-7, HRN EN 15316-4-2. U ovom radu uspoređena su sljedeća tehnička rješenja sustava grijanja, hlađenja i pripreme potrošne tople vode: 1. Dizalica topline zrak-voda s rekuperacijom i booster dizalica topline voda-voda 2. Dizalica topline voda-voda s rekuperacijom i booster dizalica topline voda-voda 3. Dizalica topline voda-voda bez rekuperacije i booster dizalica topline voda-voda 4. Kotao na drvenu sječku, rashladnik zrak-voda i booster dizalica topline voda-voda 5. Kotao na drvenu sječku i rashladnik zrak-voda Booster dizalica topline služi za pripremu potrošne tople vode temperature 60°C. Za svako tehničko rješenje priložena je shema spajanja sustava. Financijski najpovoljnije rješenje te s najmanjim utroškom primarne energije i emisijom CO2 je tehničko rješenje broj 5. Najskuplje i s većim utroškom primarne energije te s većom emisijom CO2 je tehničko rješenje broj 1. Usporedbom ukupnih troškova nakon perioda od 15 godina, tehničko rješenje broj 1 je 26% skuplje od tehničkog rješenja broj 5.Within this thesis, several technical solutions for heating, cooling and preparation of domestic hot water systems were compared for a reference low-energy hotel building, based on criteria of primary energy, investment costs and operating costs. The reference hotel building is located in Primorska Hrvatska (Coastal Croatia) and has seven levels. The total floor area is 6.912 m2 and the needed generator's heating capacity is a minimum of 260 kW while the cooling capacity is 400 kW. The building is divided into three zones. Zone number 1, rooms, is located on floors from 2 to 6. Zone number 1 is naturally ventilated and has a circulation loop for DHW. Zone number 2, kitchen, is on the first floor. Zone number 2 is mechanically ventilated and has no circulation loop for DHW. Zone number 3, common areas, is located on the ground level and on the first floor. Zone number 3 is mechanically ventilated and has no circulation loop for DHW. Envisaged heating/cooling system is two pipe with fan coils. Heating regime is 45/40°C while the cooling regime is 7/12°C. Energy need for heating QH,nd and energy need for cooling QC,nd were calculated according to HRN EN ISO 13790 using both monthly method and simple hourly method and results of both methods were compared. Following technical solutions for heating, cooling and DHW systems were compared: 1. Air-to-water heat pump with condenser heat recovery and booster heat pump water-to-water 2. Water-to-water heat pump with condenser heat recovery and booster heat pump water-to-water 3. Water-to-water heat pump without condenser heat recovery and booster heat pump water-to-water 4. Biomass boiler, air-to-water chiller and booster heat pump water-to-water 5. Biomass boiler and air-to-water chiller Booster heat pump is used for the preparation of 60°C domestic hot water. An assembly diagram is provided for each technical solution. The most expensive and with a big usage of primary energy and CO2 emission was technical solution number 1. The least expensive and with the lowest usage of primary energy and CO2 emission was technical solution number 5

MicroRNA-22 Gates Long-Term Heterosynaptic Plasticity in Aplysia through Presynaptic Regulation of CPEB and Downstream Targets

The maintenance phase of memory-related long-term facilitation (LTF) of synapses between sensory and motor neurons of the gill-withdrawal reflex of Aplysia depends on a serotonin (5-HT)-triggered presynaptic upregulation of CPEB, a functional prion that regulates local protein synthesis at the synapse. The mechanisms whereby serotonin regulates CPEB levels in presynaptic sensory neurons are not known. Here, we describe a sensory neuron-specific microRNA 22 (miR-22) that has multiple binding sites on the mRNA of CPEB and inhibits it in the basal state. Serotonin triggers MAPK/Erk-dependent downregulation of miR-22, thereby upregulating the expression of CPEB, which in turn regulates, through functional CPE elements, the presynaptic expression of atypical PKC (aPKC), another candidate regulator of memory maintenance. Our findings support a model in which the neurotransmitter-triggered downregulation of miR-22 coordinates the regulation of genes contributing synergistically to the long-term maintenance of memory-related synaptic plasticity

A Thalamic Orphan Receptor Drives Variability in Short-Term Memory.

Working memory is a form of short-term memory that involves maintaining and updating task-relevant information toward goal-directed pursuits. Classical models posit persistent activity in prefrontal cortex (PFC) as a primary neural correlate, but emerging views suggest additional mechanisms may exist. We screened ∼200 genetically diverse mice on a working memory task and identified a genetic locus on chromosome 5 that contributes to a substantial proportion (17%) of the phenotypic variance. Within the locus, we identified a gene encoding an orphan G-protein-coupled receptor, Gpr12, which is sufficient to drive substantial and bidirectional changes in working memory. Molecular, cellular, and imaging studies revealed that Gpr12 enables high thalamus-PFC synchrony to support memory maintenance and choice accuracy. These findings identify an orphan receptor as a potent modifier of short-term memory and supplement classical PFC-based models with an emerging thalamus-centric framework for the mechanistic understanding of working memory