Plummer NW, Ungewitter EK, Smith KG, Yao HH, Jensen P.
PMID: 28875587 | DOI: 10.1002/dvg.23067
Recombinase responsive mouse lines expressing diphtheria toxin subunit A (DTA) are well established tools for targeted ablation of genetically defined cell populations. Here we describe a new knock-in allele at the Gt(Rosa)26Sor locus that retains the best features of previously described DTA alleles-including a CAG promoter, attenuated mutant DTA cDNA, and ubiquitous EGFP labeling-with the addition of a Cre-dependent FLEx switch for tight control of expression. The FLEx switch consists of two pairs of antiparallel lox sites requiring Cre-mediated recombination for inversion of the DTA to the proper orientation for transcription. We demonstrate its utility by Cre-dependent ablation of both a broad domain in the embryonic nervous system and a discrete population of cells in the fetal gonads. We conclude that this new DTA line is useful for targeted ablation of genetically-defined cell populations.
Kouvaros, S;Bizup, B;Solis, O;Kumar, M;Ventriglia, E;Curry, FP;Michaelides, M;Tzounopoulos, T;
PMID: 37294760 | DOI: 10.1126/sciadv.adf3525
Synaptic zinc is a neuromodulator that shapes synaptic transmission and sensory processing. The maintenance of synaptic zinc is dependent on the vesicular zinc transporter, ZnT3. Hence, the ZnT3 knockout mouse has been a key tool for studying the mechanisms and functions of synaptic zinc. However, the use of this constitutive knockout mouse has notable limitations, including developmental, compensatory, and brain and cell type specificity issues. To overcome these limitations, we developed and characterized a dual recombinase transgenic mouse, which combines the Cre and Dre recombinase systems. This mouse allows for tamoxifen-inducible Cre-dependent expression of exogenous genes or knockout of floxed genes in ZnT3-expressing neurons and DreO-dependent region and cell type-specific conditional ZnT3 knockout in adult mice. Using this system, we reveal a neuromodulatory mechanism whereby zinc release from thalamic neurons modulates N-methyl-d-aspartate receptor activity in layer 5 pyramidal tract neurons, unmasking previously unknown features of cortical neuromodulation.
Dietschi, Q;Tuberosa, J;Fodoulian, L;Boillat, M;Kan, C;Codourey, J;Pauli, V;Feinstein, P;Carleton, A;Rodriguez, I;
PMID: 36383665 | DOI: 10.1126/sciadv.abn7450
Rodents perceive pheromones via vomeronasal receptors encoded by highly evolutionarily dynamic Vr and Fpr gene superfamilies. We report here that high numbers of V1r pseudogenes are scattered in mammalian genomes, contrasting with the clustered organization of functional V1r and Fpr genes. We also found that V1r pseudogenes are more likely to be expressed when located in a functional V1r gene cluster than when isolated. To explore the potential regulatory role played by the association of functional vomeronasal receptor genes with their clusters, we dissociated the mouse Fpr-rs3 from its native cluster via transgenesis. Singular and specific transgenic Fpr-rs3 transcription was observed in young vomeronasal neurons but was only transient. Our study of natural and artificial dispersed gene duplications uncovers the existence of transcription-stabilizing elements not coupled to vomeronasal gene units but rather associated with vomeronasal gene clusters and thus explains the evolutionary conserved clustered organization of functional vomeronasal genes.
Coverdell, TC;Abraham-Fan, RJ;Wu, C;Abbott, SBG;Campbell, JN;
PMID: 35705034 | DOI: 10.1016/j.celrep.2022.110962
Motor control of the striated esophagus originates in the nucleus ambiguus (nAmb), a vagal motor nucleus that also contains upper airway motor neurons and parasympathetic preganglionic neurons for the heart and lungs. We disambiguate nAmb neurons based on their genome-wide expression profiles, efferent circuitry, and ability to control esophageal muscles. Our single-cell RNA sequencing analysis predicts three molecularly distinct nAmb neuron subtypes and annotates them by subtype-specific marker genes: Crhr2, Vipr2, and Adcyap1. Mapping the axon projections of the nAmb neuron subtypes reveals that Crhr2nAmb neurons innervate the esophagus, raising the possibility that they control esophageal muscle function. Accordingly, focal optogenetic stimulation of cholinergic Crhr2+ fibers in the esophagus results in contractions. Activating Crhr2nAmb neurons has no effect on heart rate, a key parasympathetic function of the nAmb, whereas activating all of the nAmb neurons robustly suppresses heart rate. Together, these results reveal a genetically defined circuit for motor control of the esophagus.
Ventral pallidum DRD3 potentiates a pallido-habenular circuit driving accumbal dopamine release and cocaine seeking
Pribiag, H;Shin, S;Wang, EH;Sun, F;Datta, P;Okamoto, A;Guss, H;Jain, A;Wang, XY;De Freitas, B;Honma, P;Pate, S;Lilascharoen, V;Li, Y;Lim, BK;
PMID: 34048697 | DOI: 10.1016/j.neuron.2021.05.002
Drugs of abuse induce persistent remodeling of reward circuit function, a process thought to underlie the emergence of drug craving and relapse to drug use. However, how circuit-specific, drug-induced molecular and cellular plasticity can have distributed effects on the mesolimbic dopamine reward system to facilitate relapse to drug use is not fully elucidated. Here, we demonstrate that dopamine receptor D3 (DRD3)-dependent plasticity in the ventral pallidum (VP) drives potentiation of dopamine release in the nucleus accumbens during relapse to cocaine seeking after abstinence. We show that two distinct VP DRD3+ neuronal populations projecting to either the lateral habenula (LHb) or the ventral tegmental area (VTA) display different patterns of activity during drug seeking following abstinence from cocaine self-administration and that selective suppression of elevated activity or DRD3 signaling in the LHb-projecting population reduces drug seeking. Together, our results uncover how circuit-specific DRD3-mediated plasticity contributes to the process of drug relapse.
Kaneko, K;Sato, Y;Uchino, E;Toriu, N;Shigeta, M;Kiyonari, H;Endo, S;Fukuma, S;Yanagita, M;
PMID: 35644281 | DOI: 10.1016/j.kint.2022.04.026
Erythropoietin (Epo) is produced by a subpopulation of resident fibroblasts in the healthy kidney. We have previously demonstrated that, during kidney fibrosis, kidney fibroblasts including Epo-producing cells transdifferentiate into myofibroblasts and lose their Epo-producing ability. However, it remains unclear whether Epo-producing cells survive and transform into myofibroblasts during fibrosis because previous studies did not specifically label Epo-producing cells in pathophysiological conditions. Here, we generated EpoCreERT2/+ mice, a novel mouse strain that enables labeling of Epo-producing cells at desired time points and examined the behaviors of Epo-producing cells under pathophysiological conditions. Lineage -labeled cells that were producing Epo when labeled were found to be a small subpopulation of fibroblasts located in the interstitium of the kidney, and their number increased during phlebotomy-induced anemia. Around half of lineage-labeled cells expressed Epo mRNA, and this percentage was maintained even 16 weeks after recombination, supporting the idea that a distinct subpopulation of cells with Epo-producing ability makes Epo repeatedly. During fibrosis caused by ureteral obstruction, EpoCreERT2/+ -labeled cells were found to transdifferentiate into myofibroblasts with concomitant loss of Epo-producing ability, and their numbers and the proportion among resident fibroblasts increased during fibrosis, indicating their high proliferative capacity. Finally, we confirmed that EpoCreERT2/+-labeled cells that lost their Epo-producing ability during fibrosis regained their ability after kidney repair due to relief of the ureteral obstruction. Thus, our analyses have revealed previously unappreciated characteristic behaviors of Epo-producing cells, which had not been clearly distinguished from those of resident fibroblasts.
Graham, K;Spruston, N;Bloss, EB;
PMID: 34686328 | DOI: 10.1016/j.celrep.2021.109837
The selection of goal-directed behaviors is supported by neural circuits located within the frontal cortex. Frontal cortical afferents arise from multiple brain areas, yet the cell-type-specific targeting of these inputs is unclear. Here, we use monosynaptic retrograde rabies mapping to examine the distribution of afferent neurons targeting distinct classes of local inhibitory interneurons and excitatory projection neurons in mouse infralimbic frontal cortex. Interneurons expressing parvalbumin, somatostatin, or vasoactive intestinal peptide receive a large proportion of inputs from the hippocampus, while interneurons expressing neuron-derived neurotrophic factor receive a large proportion of inputs from thalamic regions. A similar dichotomy is present among the four different excitatory projection neurons. These results show a prominent bias among long-range hippocampal and thalamic afferent systems in their targeting to specific sets of frontal cortical neurons. Moreover, they suggest the presence of two distinct local microcircuits that control how different inputs govern frontal cortical information processing.
Adams JM, Pei H, Sandoval DA, Seeley RJ, Chang RB, Liberles SD, Olson DP.
PMID: 29776968 | DOI: 10.2337/db17-1385
Glucagon-like peptide-1 receptor (GLP-1R) agonists are FDA-approved weight loss drugs. Despite their widespread use, the sites of action through which GLP-1R agonists (GLP1RAs) impact appetite and body weight are still not fully understood. Here, we determined whether GLP-1Rs in either GABAergic or glutamatergic neurons are necessary for the acute and chronic effects of the GLP1RA liraglutide on food intake, visceral illness, body weight and neural network activation. We found that mice lacking GLP-1Rs in vGAT-expressing GABAergic neurons responded identically to controls in all parameters measured, whereas deletion of GLP-1Rs in vGlut2-expressing glutamatergic neurons eliminated liraglutide-induced weight loss and visceral illness and severely attenuated its effects on feeding. Concomitantly, deletion of GLP-1Rs from glutamatergic neurons completely abolished the neural network activation observed after liraglutide administration. We conclude that liraglutide activates a dispersed but discrete neural network to mediate its physiological effects, and that these effects require GLP-1R expression on glutamatergic but not GABAergic neurons.
Furlan, A;Corona, A;Boyle, S;Sharma, R;Rubino, R;Habel, J;Gablenz, EC;Giovanniello, J;Beyaz, S;Janowitz, T;Shea, SD;Li, B;
PMID: 36266470 | DOI: 10.1038/s41593-022-01178-3
Obesity is a global pandemic that is causally linked to many life-threatening diseases. Apart from some rare genetic conditions, the biological drivers of overeating and reduced activity are unclear. Here, we show that neurotensin-expressing neurons in the mouse interstitial nucleus of the posterior limb of the anterior commissure (IPAC), a nucleus of the central extended amygdala, encode dietary preference for unhealthy energy-dense foods. Optogenetic activation of IPACNts neurons promotes obesogenic behaviors, such as hedonic eating, and modulates food preference. Conversely, acute inhibition of IPACNts neurons reduces feeding and decreases hedonic eating. Chronic inactivation of IPACNts neurons recapitulates these effects, reduces preference for sweet, non-caloric tastants and, furthermore, enhances locomotion and energy expenditure; as a result, mice display long-term weight loss and improved metabolic health and are protected from obesity. Thus, the activity of a single neuronal population bidirectionally regulates energy homeostasis. Our findings could lead to new therapeutic strategies to prevent and treat obesity.
Cheung, V;Chung, P;Bjorni, M;Shvareva, VA;Lopez, YC;Feinberg, EH;
PMID: 34936877 | DOI: 10.1016/j.celrep.2021.110131
Behavior arises from concerted activity throughout the brain. Consequently, a major focus of modern neuroscience is defining the physiology and behavioral roles of projection neurons linking different brain areas. Single-cell RNA sequencing has facilitated these efforts by revealing molecular determinants of cellular physiology and markers that enable genetically targeted perturbations such as optogenetics, but existing methods for sequencing defined projection populations are low throughput, painstaking, and costly. We developed a straightforward, multiplexed approach, virally encoded connectivity transgenic overlay RNA sequencing (VECTORseq). VECTORseq repurposes commercial retrogradely infecting viruses typically used to express functional transgenes (e.g., recombinases and fluorescent proteins) by treating viral transgene mRNA as barcodes within single-cell datasets. VECTORseq is compatible with different viral families, resolves multiple populations with different projection targets in one sequencing run, and identifies cortical and subcortical excitatory and inhibitory projection populations. Our study provides a roadmap for high-throughput identification of neuronal subtypes based on connectivity.