-
Journal of Psychopharmacology (Oxford,... Jun 2024The highly selective 5-HT serotonin receptor "biased" agonists NLX-101 and NLX-204 display, like ketamine, potent and efficacious rapid-acting antidepressant (RAAD)...
The 5-HT1A receptor biased agonists, NLX-204 and NLX-101, like ketamine, elicit rapid-acting antidepressant activity in the rat chronic mild stress model via cortical mechanisms.
BACKGROUND
The highly selective 5-HT serotonin receptor "biased" agonists NLX-101 and NLX-204 display, like ketamine, potent and efficacious rapid-acting antidepressant (RAAD) activity in the rat chronic mild stress (CMS) model with systemic (i.p.) administration. They rapidly (within 1 day) reverse anhedonia (i.e., CMS-induced sucrose consumption deficit), attenuate working memory deficit (novel object recognition: NOR), and decrease anxiety behavior in the elevated-plus maze (EPM).
AIMS
Here, we sought to explore the contribution of prefrontal cortex (PFC) 5-HT receptor activation in the RAAD activity of NLX compounds.
RESULTS/OUTCOMES
In male Wistar rats, unilateral PFC microinjections of NLX-204 and NLX-101 (16 µg), like ketamine (10 µg), reproduced the effects of their systemic administration: they reversed CMS-induced sucrose consumption deficit, attenuated anxiety (EPM), and reduced working memory deficits (NOR). In addition, unilateral PFC microinjections of the selective 5-HT antagonist, WAY-100,635 (2 µg), attenuated the beneficial effects of systemic NLX-204 and NLX-101 (0.16 mg/kg i.p.) in the sucrose intake and NOR models, indicating that these compounds exert their RAAD activity specifically through activation of PFC 5-HT receptors.
CONCLUSIONS/INTERPRETATION
These data indicate that 5-HT receptor biased agonists share with ketamine a common neuroanatomical site for RAAD activity, which can be obtained not only by targeting glutamatergic/NMDA neurotransmission (ketamine's primary mechanism of action) but also by activating 5-HT receptors, as is the case for the NLX compounds. The present observations also reinforce the notion that biased agonism at 5-HT receptors constitutes a promising strategy to achieve RAAD effects, with additional benefits against cognitive deficits and anxiety in depressed patients, without ketamine's troublesome side effects.
PubMed: 38825869
DOI: 10.1177/02698811241254832 -
Molecular Biology Reports Jun 2024Microinjection is a direct procedure for delivering various compounds via micropipette into individual cells. Combined with the CRISPR/Cas9 editing technology, it has...
BACKGROUND
Microinjection is a direct procedure for delivering various compounds via micropipette into individual cells. Combined with the CRISPR/Cas9 editing technology, it has been used to produce genetically engineered animal cells. However, genetic micromanipulation of intact plant cells has been a relatively unexplored area of research, partly due to the cytological characteristics of these cells. This study aimed to gain insight into the genetic micromanipulation of wheat microspores using microinjection procedures combined with the CRISPR/Cas9 editing system targeting the Ms2 gene.
METHODS AND RESULTS
Microspores were first reprogrammed by starvation and heat shock treatment to make them structurally suitable for microinjection. The large central vacuole was fragmented and the nucleus with cytoplasm was positioned in the center of the cell. This step and an additional maltose gradient provided an adequate source of intact single cells in the three wheat genotypes. The microcapillary was inserted into the cell through the germ pore to deliver a working solution with a fluorescent marker. This procedure was much more efficient and less harmful to the microspore than inserting the microcapillary through the cell wall. The CRISPR/Cas9 binary vectors injected into reprogrammed microspores induced mutations in the target Ms2 gene with deletions ranging from 1 to 16 bp.
CONCLUSIONS
This is the first report of successful genome editing in an intact microspore/wheat cell using the microinjection technique and the CRISPR/Cas9 editing system. The study presented offers a range of molecular and cellular biology tools that can aid in genetic micromanipulation and single-cell analysis.
Topics: Triticum; CRISPR-Cas Systems; Gene Editing; Microinjections; Mutation; Pollen
PubMed: 38824203
DOI: 10.1007/s11033-024-09644-w -
Neuroscience May 2024Spreading depolarization (SD) is a slowly propagating wave of prolonged activation followed by a period of synaptic suppression. Some prior reports have shown...
Spreading depolarization (SD) is a slowly propagating wave of prolonged activation followed by a period of synaptic suppression. Some prior reports have shown potentiation of synaptic transmission after recovery from synaptic suppression and noted similarities with the phenomenon of long-term potentiation (LTP). Since SD is increasingly recognized as participating in diverse neurological disorders, it is of interest to determine whether SD indeed leads to a generalized and sustained long-term strengthening of synaptic connections. We performed a characterization of SD-induced potentiation, and tested whether distinctive features of SD, including adenosine accumulation and swelling, contribute to reports of SD-induced plasticity. Field excitatory postsynaptic potentials (fEPSPs) were recorded in the hippocampal CA1 subregion of murine brain slices, and SD elicited using focal microinjection of KCl. A single SD was sufficient to induce a consistent potentiation of slope and amplitude of fEPSPs. Both AMPA- and NMDA-receptor mediated components were enhanced. Potentiation peaked ∼20 min after SD recovery and was sustained for ∼30 min. However, fEPSP amplitude and slope decayed over an extended 2-hour recording period and was estimated to reach baseline after ∼3 h. Potentiation was saturated after a single SD and adenosine A1 receptor activation did not mask additional potentiation. Induction of LTP with theta-burst stimulation was not altered by prior induction of SD and molecular mediators known to block LTP induction did not block SD-induced potentiation. Together, these results indicate an intermediate duration potentiation that is distinct from hippocampal LTP and may have implications for circuit function for 1-2 h following SD.
PubMed: 38821241
DOI: 10.1016/j.neuroscience.2024.05.035 -
Fish Physiology and Biochemistry May 2024Lines with few or no pigment cells have been established in fishes, and these lines are useful for bioimaging. The transparent goldfish (tra) line previously established...
Lines with few or no pigment cells have been established in fishes, and these lines are useful for bioimaging. The transparent goldfish (tra) line previously established by N-ethyl-N-nitrosourea (ENU) mutagenesis is also suitable for such experiments. However, in the case of tra, leucophores form in the adult fish, making it difficult to observe the organs inside body from outside the body. In this study, we attempted to create a knockout line of the pax7a and pax7b genes, which are thought to be involved in the formation of leucophores, to further improve the transparency of tra strain.Mutations were introduced by microinjection of the CRISPR/Cas9 mixture into single-cell embryos, mutant individuals were found in F0, and the next generation was generated to confirm the mutation patterns. As a result, multiple mutation patterns, including knockout, were obtained. The same pattern of knockout F1 with pax7a and pax7b mutations was crossed to generate a homozygous knockout in F2.In the resulting pax7b (tra) fish but not in pax7a (tra) fish, the number of leucophores was reduced compared to that in tra, and the transparency of the body was improved. It was suggested that pax7b plays an important role in leucophore formation in goldfish. The established transparent pax7b (tra) goldfish line will be a useful model for bioimaging of the body interior.
PubMed: 38819758
DOI: 10.1007/s10695-024-01364-z -
Heliyon May 2024Peroxiredoxin 1 (Prx1) is an antioxidant protein that may promote the carcinogenesis in oral leukoplakia (OLK). To investigate the effect of Prx1 on the oral mucosal...
Peroxiredoxin 1 (Prx1) is an antioxidant protein that may promote the carcinogenesis in oral leukoplakia (OLK). To investigate the effect of Prx1 on the oral mucosal epithelium of OLK, we generated a Prx1 conditional knockout (cKO) mouse model. The mRNA and gRNA were generated using the clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) technique. An infusion cloning method was used to construct a homologous recombination vector. To obtain the F0 generation mice, fertilized eggs of C57BL/6J mice were microinjected with Cas9 mRNA, gRNA, and a donor vector. Polymerase chain reaction (PCR) amplification and sequencing were used to identify F1 generation mice. Using the cyclization recombination-enzyme-locus of the X-overP1 (Cre-loxP) system, we created a Prx1 cKO mouse model, and the effectiveness of the knockout was confirmed through immunohistochemistry. We examined the influence of Prx1 knockout on the occurrence of OLK in mice by constructing a model of tongue mucosa carcinogenesis induced by 4-nitroquinoline-1-oxide (4NQO). Prx1 modification was present in the F1 generation, as evidenced by PCR amplification and sequencing. Prx1: Cre + mice exhibited normal growth and fertility. Immunohistochemical analysis revealed that tongue epithelial cells in Prx1: Cre + mice displayed a distinct deletion of Prx1. An examination of the heart, liver, spleen, lung, and kidney tissues revealed no visible histological changes. Histological analysis showed a reduction in the occurrence of the malignant transformation of OLK in the tongue tissues of Prx1: Cre + mice. Ki67 immunostaining showed that Prx1 knockout significantly inhibited cell proliferation in the tongue epithelial. Our research developed a conditional knockout mouse model for Prx1. The obtained results provide insights into the function of Prx1 in the development of oral cancer and emphasize its potential as a therapeutic target for precancerous oral lesions.
PubMed: 38818156
DOI: 10.1016/j.heliyon.2024.e31227 -
Cells & Development May 2024The oocyte expresses certain genes during folliculogenesis to regulate the acquisition of oocyte competence. Oocyte competence, or oocyte quality, is directly related to...
The oocyte expresses certain genes during folliculogenesis to regulate the acquisition of oocyte competence. Oocyte competence, or oocyte quality, is directly related to the ability of the oocyte to result in a successful pregnancy following fertilization. Presently, approximately 40 % of bovine embryos will develop to the blastocyst stage in vitro. Characterization of factors regulating these processes is crucial to improve the efficiency of bovine in vitro embryo production. We demonstrated that the secreted protein, agouti-signaling protein (ASIP) is highly abundant in the bovine oocyte and aimed to characterize its spatiotemporal expression profile in the ovary and throughout early embryonic development. In addition to oocyte expression, ASIP was detected in granulosa, cumulus, and theca cells isolated from antral follicles. Both gene expression data and immunofluorescent staining indicated ASIP declines with oocyte maturation which may indicate a potential role for ASIP in the attainment of oocyte competence. Microinjection of zygotes using small interfering RNA targeting ASIP led to a 16 % reduction in the rate of development to the blastocyst stage. Additionally, we examined potential ASIP signaling mechanisms through which ASIP may function to establish oocyte developmental competence. The expression of melanocortin receptor 3 and 4 and the coreceptor attractin was detected in the oocyte and follicular cells. The addition of cortisol during in vitro maturation was found to increase significantly oocyte ASIP levels. In conclusion, these results suggest a functional role for ASIP in promoting oocyte maturation and subsequent embryonic development, potentially through signaling mechanisms involving cortisol.
PubMed: 38815807
DOI: 10.1016/j.cdev.2024.203930 -
Neurochemical Research May 2024Since the clinical introduction of general anesthesia, its underlying mechanisms have not been fully elucidated. The ventral tegmental area (VTA) and parabrachial...
Since the clinical introduction of general anesthesia, its underlying mechanisms have not been fully elucidated. The ventral tegmental area (VTA) and parabrachial nucleus (PBN) play pivotal roles in the mechanisms underlying general anesthesia. However, whether dopaminergic (DA) projections from the VTA to the PBN play a role in mediating the effects of general anesthesia is unclear. We microinjected 6-hydroxydopamine into the PBN to damage tyrosine hydroxylase positive (TH+) neurons and found a prolonged recovery time from propofol anesthesia. We used calcium fiber photometry recording to explore the activity of TH + neurons in the PBN. Then, we used chemogenetic and optogenetic approaches either activate the VTA-PBN pathway, shortening the propofol anesthesia emergence time, or inhibit this pathway, prolonging the emergence time. These data indicate the crucial involvement of TH + neurons in the PBN in regulating emergence from propofol anesthesia, while the activation of the VTA-PBN pathway facilitates the emergence of propofol anesthesia.
PubMed: 38814359
DOI: 10.1007/s11064-024-04169-x -
Scientific Reports May 2024Dysfunction of subcortical D2-like dopamine receptors (DRs) can lead to positive symptoms of schizophrenia, and their analog, the increased locomotor activity in...
Dysfunction of subcortical D2-like dopamine receptors (DRs) can lead to positive symptoms of schizophrenia, and their analog, the increased locomotor activity in schizophrenia model MAM-E17 rats. The ventral pallidum (VP) is a limbic structure containing DRs. The DR antagonist sulpiride is a widespread antipsychotic drug, which can alleviate positive symptoms in human patients. However, it is still not known how sulpiride can influence positive symptoms via VP DRs. We hypothesize that the microinjection of sulpiride into the VP can normalize hyperactivity in MAM-E17 rats. In addition, recently, we showed that the microinjection of sulpirid into the VP induces place preference in neurotypical rats. Thus, we aimed to test whether intra-VP sulpiride can also have a rewarding effect in MAM-E17 rats. Therefore, open field-based conditioned place preference (CPP) test was applied in neurotypical (SAL-E17) and MAM-E17 schizophrenia model rats to test locomotor activity and the potential locomotor-reducing and rewarding effects of sulpiride. Sulpiride was microinjected bilaterally in three different doses into the VP, and the controls received only vehicle. The results of the present study demonstrated that the increased locomotor activity of the MAM-E17 rats was caused by habituation disturbance. Accordingly, larger doses of sulpiride in the VP reduce the positive symptom-analog habituation disturbance of the MAM-E17 animals. Furthermore, we showed that the largest dose of sulpiride administered into the VP induced CPP in the SAL-E17 animals but not in the MAM-E17 animals. These findings revealed that VP DRs play an important role in the formation of positive symptom-like habituation disturbances in MAM-E17 rats.
Topics: Animals; Sulpiride; Schizophrenia; Antipsychotic Agents; Rats; Basal Forebrain; Disease Models, Animal; Male; Microinjections; Habituation, Psychophysiologic; Locomotion; Receptors, Dopamine D2
PubMed: 38811614
DOI: 10.1038/s41598-024-63059-y -
The Journal of Neuroscience : the... May 2024Neurons in the caudal nucleus of the solitary tract (cNTS) and intermediate reticular nucleus (IRt) that express the glucagon gene give rise to GLP1-immunopositive...
Populations of hindbrain glucagon-like peptide 1 (GLP1) neurons that innervate the hypothalamic PVH, thalamic PVT, or limbic forebrain BST have axon collaterals that reach all central regions innervated by GLP1 neurons.
Neurons in the caudal nucleus of the solitary tract (cNTS) and intermediate reticular nucleus (IRt) that express the glucagon gene give rise to GLP1-immunopositive axons in the spinal cord and many subcortical brain regions. Central GLP1 receptor signaling contributes to motivated behavior and stress responses in rats and mice, in which hindbrain GLP1 neurons are activated to express cFos in a metabolic state-dependent manner. The present study examined whether GLP1 inputs to distinct brain regions arise from distinct subsets of -expressing neurons, and mapped the collective distribution of axon collaterals arising from projection-defined GLP1 neural populations. Using our Gcg-Cre knock-in rat model, Cre-dependent adeno-associated virus (AAV1) tracing was conducted in adult male and female rats to compare axonal projections of IRt vs. cNTS GLP1 neurons. Overlapping axonal projections were observed in all brain regions that receive GLP1 input, with the caveat that cNTS injections produced Cre-dependent labeling of some IRt neurons, and vice-versa. In additional experiments, specific diencephalic or limbic forebrain nuclei were microinjected with Cre-dependent retrograde AAVs (AAVrg) expressing reporters that fully labeled the axon collaterals of transduced GLP1 neural populations. AAVrg injected into each forebrain site labeled expressing neurons in both the cNTS and IRt. The collective axon collaterals of these labeled neurons entered the spinal cord and every brain region previously reported to contain GLP1-positive axons. These results indicate that axons arising from populations of GLP1 neurons that innervate the thalamic PVT, hypothalamic PVH, and/or limbic forebrain BST collectively innervate all central regions that receive GLP1 axonal input. Our novel anatomical findings indicate that target-defined populations of forebrain-projecting GLP1 neurons collectively project to downstream target regions in a widespread sprinkler-type manner, although collateralized axons arising from individual GLP1 projection neurons remain to be defined. Considered together with results from studies investigating the role of central GLP1 receptor signaling pathways in physiology and behavior, these findings support our emerging view that hindbrain -expressing neurons are positioned to simultaneously modulate synaptic transmission in widespread spinal cord, brainstem, hypothalamic, and limbic forebrain circuits in a metabolic state-dependent manner.
PubMed: 38811166
DOI: 10.1523/JNEUROSCI.2063-23.2024 -
Heliyon May 2024The reserve of glycogen is essential for embryonic development. In oviparous fish, egg is an isolated system after egg laying with all the required energy deposits by...
The reserve of glycogen is essential for embryonic development. In oviparous fish, egg is an isolated system after egg laying with all the required energy deposits by their mothers. However, the key regulated factor mediates the storage of maternal glycogen reserve which support for embryogenesis in the offspring is largely unknown. Glycogen synthase (GYS) is a central enzyme for glycogen synthesis. In our previous study, we generated a knockout zebrafish line, showed an embryonic developmental defect in F generation. In this study, firstly we determined that the was maternal origin by backcrossing the F mutant with wildtype lines. PAS staining and glycogen content measurement showed that glycogen reserve was reduced both in ovaries and embryos in the mutant group compared to wildtypes. Free glucose measurement analysis showed a 50 % of reduction in mutant embryos compared to wildtype embryos at 24 hpf; showed an approximal 50 % of reduction in mutant adults compared to wildtypes. Microinjection of 2-NBDG in embryos and comparison of fluorescent signal demonstrated that glucose uptake ability was decreased in the mutant embryos, indicating an impaired glucose metabolism. Untargeted metabolomics analysis then was employed and revealed that key modified metabolites enriched into vitamin B pathway, carbohydrate and unsaturated fatty acid pathways. These results demonstrated that played a role on glycogen metabolism, involved into the maternal glycogen reserve which essentially contribute to embryonic development.
PubMed: 38803914
DOI: 10.1016/j.heliyon.2024.e31149