1
|
Kagan D, Batabyal A, Lukowiak K. Remember the poke: microRNAs are required for long-term memory formation following operant conditioning in Lymnaea. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2023; 209:403-410. [PMID: 36622417 DOI: 10.1007/s00359-022-01604-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 12/14/2022] [Accepted: 12/17/2022] [Indexed: 01/10/2023]
Abstract
MicroRNAs (miRNAs) play an important role in learning and memory formation by controlling the expression of genes through epigenetic processes. Although miRNAs unquestionably play a role in memory, past literature focusing on whether miRNAs play key roles in the consolidation of associative long-term memory in Lymnaea contained confounding variables. Using operant conditioning of aerial respiratory behaviour, we investigated long-term memory (LTM) formation after injection of poly-L-lysine (PLL), an inhibitor of Dicer-mediated miRNA biogenesis, in Lymnaea stagnalis. Homeostatic breathing experiments were also performed to test whether PLL affects breathing. Homeostatic breathing was significantly suppressed 45 min but not 24 h after PLL injection. The operant conditioning procedure involved two 30-min training sessions separated by 1 h to cause LTM. Using this operant conditioning procedure, LTM formation was significantly impaired when snails were injected with PLL 15 min after the second training session. In contrast, when snails were injected with PLL 24 h before the first training session, LTM formation was not impaired. These results are consistent with past literature and highlight an important role for miRNAs in LTM formation.
Collapse
Affiliation(s)
- Diana Kagan
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada
| | - Anuradha Batabyal
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada
| | - Ken Lukowiak
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada.
| |
Collapse
|
2
|
Airway hypersensitivity induced by eosinophil granule-derived cationic proteins. Pulm Pharmacol Ther 2019; 57:101804. [PMID: 31096035 DOI: 10.1016/j.pupt.2019.101804] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 05/07/2019] [Accepted: 05/11/2019] [Indexed: 01/05/2023]
Abstract
Vagal bronchopulmonary C-fiber sensory nerves play an important role in the manifestation of airway hypersensitivity, a common and prominent pathophysiological feature of airway inflammatory diseases. Eosinophil granule-derived cationic proteins are known to be involved in the mucosal damage and development of bronchial hyperresponsiveness during allergic airway inflammation. In view of these background information, we have carried out a series of studies to investigate the effect of cationic proteins on these C-fiber afferents and the mechanism(s) possibly involved; a summary of these studies is presented in this mini-review. Intra-tracheal instillation of either eosinophil granule-derived (e.g., major basic protein, MBP) or synthetic cationic proteins (e.g., poly-l-lysine) induced a sporadic, but intense and lingering discharge of pulmonary C-fibers, and greatly enhanced the chemical and mechanical sensitivities of these afferents in anesthetized rats. The stimulatory and sensitizing effects of these proteins were completely nullified when their cationic charges were neutralized or removed. Furthermore, in isolated rat bronchopulmonary capsaicin-sensitive neurons, eosinophil granule cationic proteins induced a direct and long-lasting (>60 min) but reversible sensitizing effect on their responses to chemical and electrical stimulations. More importantly, our study showed that these cationic proteins exerted an inhibitory effect on the sustained delayed-rectifier voltage-gated K+ current and the A-type, fast-inactivating K+ current; these actions were at least in part responsible for the sensitizing effect in these neurons. In awake mice, intra-tracheal instillation of MBP also induced a slowly developing (peaking in 2-3 days), progressive and sustained (lasting for 3-7 days) elevation of the cough responses to inhaled irritant gases. Taken together, these findings suggest that the enhanced sensitivity of bronchopulmonary C-fibers induced by the eosinophil granule cationic proteins may be a contributing factor in the pathogenesis of bronchial hyperresponsiveness and chronic cough associated with eosinophilic infiltration of the airways.
Collapse
|
3
|
Ceschan NE, Bucalá V, Mateos MV, Smyth HDC, Ramírez-Rigo MV. Carrier free indomethacin microparticles for dry powder inhalation. Int J Pharm 2018; 549:169-178. [PMID: 30071308 DOI: 10.1016/j.ijpharm.2018.07.065] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 07/27/2018] [Accepted: 07/29/2018] [Indexed: 11/28/2022]
Abstract
The present studies were designed to evaluate inhalatory microparticles carrying indomethacin (IN) for potential local (specific and non-specific bronchial inflammatory asthma responses) and systemic treatments (joint inflammation, rheumatoid arthritis and osteoarthritis pain) by optimizing microparticle properties, characterizing their lung deposition, drug release, evaluating cytotoxicity and also pharmacological effect in vitro. The acidic groups of IN were complexed with the cationic groups of the polyelectrolyte polylysine in order to increase the drug water compatibility. The polylysine/indomethacin ratio was fixed and the pH was adjusted in different formulations. Microparticles were obtained by spray drying using a relatively high atomization air flowrate (742 L/min) and a high-performance cyclone in order to optimize the production of microparticles with adequate attributes for inhalatory delivery. The produced microparticles exhibited high process yield and IN loading, volumetric mean diameters smaller than 5 μm and narrow particle size distributions. According to demonstrated aerosolization performance, the powders were suitable for inhalatory indomethacin local and systemic treatments. Emitted fraction was higher than 90%, the MMAD was around 3 μm and the GSD lower than 3. The respirable fraction for particles with aerodynamic diameters smaller than 5 μm was around 29% while for particles with aerodynamic diameters smaller than 3 μm the value was around 17%. The addition of lactose as carrier worsened the aerodynamic performance of the microparticles. The developed powdered systems got wet and dissolved quickly and presented higher release rates respect to pure IN in simulated lung physiological conditions. Furthermore, the assays performed in RAW 264.7 cell line showed that the microparticles exhibited the same anti-inflammatory capability as the pure drug. The developed particles did not affect the RAW 264.7 cell viability. In conclusion, a promising powder formulation for DPIs has been developed to treat, locally and systemically, inflammatory diseases.
Collapse
Affiliation(s)
- Nazareth Eliana Ceschan
- Planta Piloto de Ingeniería Química (PLAPIQUI), CONICET - Universidad Nacional del Sur (UNS), Camino La Carrindanga km 7, 8000 Bahía Blanca, Argentina; Departamento de Biología, Bioquímica y Farmacia, UNS, San Juan 670, 8000 Bahía Blanca, Argentina
| | - Verónica Bucalá
- Planta Piloto de Ingeniería Química (PLAPIQUI), CONICET - Universidad Nacional del Sur (UNS), Camino La Carrindanga km 7, 8000 Bahía Blanca, Argentina; Departamento de Ingeniería Química, UNS, Avenida Alem 1253, 8000 Bahía Blanca, Argentina
| | - Melina Valeria Mateos
- Departamento de Biología, Bioquímica y Farmacia, UNS, San Juan 670, 8000 Bahía Blanca, Argentina; Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), 8000 Bahía Blanca, Argentina
| | - Hugh David Charles Smyth
- College of Pharmacy, The University of Texas at Austin, 2409 West University Avenue, Austin, TX, United States
| | - María Verónica Ramírez-Rigo
- Planta Piloto de Ingeniería Química (PLAPIQUI), CONICET - Universidad Nacional del Sur (UNS), Camino La Carrindanga km 7, 8000 Bahía Blanca, Argentina; Departamento de Biología, Bioquímica y Farmacia, UNS, San Juan 670, 8000 Bahía Blanca, Argentina.
| |
Collapse
|
4
|
|
5
|
Gu Q, Lim ME, Gleich GJ, Lee LY. Mechanisms of eosinophil major basic protein-induced hyperexcitability of vagal pulmonary chemosensitive neurons. Am J Physiol Lung Cell Mol Physiol 2009; 296:L453-61. [PMID: 19136577 DOI: 10.1152/ajplung.90467.2008] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
We have reported recently that eosinophil-derived basic proteins directly enhance the capsaicin- and electrical stimulation-evoked whole cell responses in rat pulmonary sensory neurons (19). Our present study further elucidates the mechanisms underlying the sensitization of pulmonary afferent nerves induced by these cationic proteins. Our results show that pretreatment with eosinophil major basic protein (MBP; 2 microM, 60 s) significantly enhanced the excitability of isolated rat vagal pulmonary chemosensitive neurons to acid and ATP in the current-clamp mode, but this potentiating effect was absent in the voltage-clamp recordings. The hyperexcitability induced by MBP was not prevented by the blockade of either transient receptor potential vanilloid type-1 receptor (TRPV1) selectively (inhibitor: AMG 9810; 1 microM, 2 min) or all TRPV1-4 channels (inhibitor: ruthenium red; 5 microM, 2 min). In addition, MBP also markedly potentiated the excitability of mouse pulmonary chemosensitive neurons, and no detectable difference was found between those isolated from wild-type and TRPV1 knockout mice. Furthermore, MBP pretreatment affected the decay time and recovery phase of the action potentials evoked by current injections and significantly inhibited both the sustained delayed-rectifier voltage-gated K(+) current (IK(dr)) and the A-type, fast-inactivating K(+) current (IK(a)) in these sensory neurons. In conclusion, our results indicate that the inhibition of IK(dr) and IK(a) should, at least in part, account for the hyperexcitability of pulmonary chemosensitive neurons induced by eosinophil-derived cationic proteins, whereas an interaction with TRPV1 channels does not seem to be required for the sensitizing effect of these proteins.
Collapse
Affiliation(s)
- Qihai Gu
- Department of Physiology, University of Kentucky Medical Center, Lexington, Kentucky 40536-0298, USA
| | | | | | | |
Collapse
|
6
|
Gu Q, Wiggers ME, Gleich GJ, Lee LY. Sensitization of isolated rat vagal pulmonary sensory neurons by eosinophil-derived cationic proteins. Am J Physiol Lung Cell Mol Physiol 2008; 294:L544-52. [DOI: 10.1152/ajplung.00271.2007] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
It has been shown that airway exposure to eosinophil-derived cationic proteins stimulated vagal pulmonary C fibers and markedly potentiated their responses to lung inflation in anesthetized rats (Lee LY, Gu Q, Gleich GJ, J Appl Physiol 91: 1318–1326, 2001). However, whether the effects resulted from a direct action of these proteins on the sensory nerves was not known. The present study was therefore carried out to determine the effects of these proteins on isolated rat vagal pulmonary sensory neurons. Our results obtained from perforated whole cell patch-clamp recordings showed that pretreatment with eosinophil major basic protein (MBP; 2 μM, 60 s) significantly increased the capsaicin-evoked inward current in these neurons; this effect peaked ∼10 min after MBP and lasted for >60 min; in current-clamp mode, MBP substantially increased the number of action potentials evoked by both capsaicin and electrical stimulation. Pretreatment with MBP did not significantly alter the input resistance of these sensory neurons. In addition, the sensitizing effect of MBP was completely abolished when its cationic charge was neutralized by mixing with a polyanion, such as low-molecular-weight heparin or poly-l-glutamic or poly-l-aspartic acid, before its delivery to the neurons. Moreover, a similar sensitizing effect was also generated by other eosinophil granule-derived proteins (e.g., eosinophil peroxidase). These results demonstrate a direct, charge-dependent, and long-lasting sensitizing effect of cationic proteins on pulmonary sensory neurons, which may contribute to the airway hyperresponsiveness associated with airway infiltration of eosinophils under pathophysiological conditions.
Collapse
|