Probes for INS

The central amygdala (CeA) is important for fear responses to discrete cues. Recent findings indicate that the CeA also contributes to states of sustained apprehension that characterize anxiety, although little is known about the neural circuitry involved. The stress neuropeptide corticotropin releasing factor (CRF) is anxiogenic and is produced by subpopulations of neurons in the lateral CeA and the dorsolateral bed nucleus of the stria terminalis (dlBST). Here we investigated the function of these CRF neurons in stress-induced anxiety using chemogenetics in male rats that express Cre recombinase from a Crh promoter. Anxiety-like behavior was mediated by CRF projections from the CeA to the dlBST and depended on activation of CRF1 receptors and CRF neurons within the dlBST. Our findings identify a CRFCeA→CRFdlBST circuit for generating anxiety-like behavior and provide mechanistic support for recent human and primate data suggesting that the CeA and BST act together to generate states of anxiety.SIGNIFICANCE STATEMENT Anxiety is a negative emotional state critical to survival, but persistent, exaggerated apprehension causes substantial morbidity. Identifying brain regions and neurotransmitter systems that drive anxiety can help in developing effective treatment. Much evidence in rodents indicates that neurons in the bed nucleus of the stria terminalis (BST) generate anxiety-like behaviors, but more recent findings also implicate neurons of the CeA. The neuronal subpopulations and circuitry that generate anxiety are currently subjects of intense investigation. Here we show that CeA neurons that release the stress neuropeptide corticotropin-releasing factor (CRF) drive anxiety-like behaviors in rats via a pathway to dorsal BST that activates local BST CRF neurons. Thus, our findings identify a CeA→BST CRF neuropeptide circuit that generates anxiety-like behavior.

Wnt signaling plays an important role in uterine organogenesis and oncogenesis. Our mRNA expression data documents the expression of various Wnt pathway members during the key stages of uterine epithelial gland development. Our data illustrates the expression of Wnt signaling inhibitors (Axin2, Sfrp2, Sfrp4, Dkk1 and Dkk3) in mice uteri at postnatal day 6 (PND 6) and day 15 (PND 15). They also describe the expression pattern of the Wnt ligands (Wnt1, Wnt2, Wnt2b, Wnt3, Wnt3a, Wnt5b, Wnt7b, Wnt8a, Wnt8b, Wnt9a, Wnt9b, Wnt10a and Wnt10b) in mice uteri with or without progesterone treatment. Detailed interpretation and discussion of these data is presented in the research article entitled “Differential Wnt signaling activity limits epithelial gland development to the anti-mesometrial side of the mouse uterus” [1].

The epithelial lining of the Fallopian tube is vital for fertility, providing nutrition to gametes, and facilitating their transport. It is composed of two major cell types: secretory cells and ciliated cells. Interestingly, human ovarian cancer precursor lesions are primarily consisting of secretory cells. It is unclear why secretory cells are the dominant cell type in these lesions. Additionally, the underlying mechanisms governing Fallopian tube epithelial homoeostasis are currently unknown. In the present study, we showed that across the different developmental stages of mouse oviduct, secretory cells are the most frequently dividing cells of the oviductal epithelium. In vivo genetic cell lineage tracing showed that secretory cells not only self-renew, but also give rise to ciliated cells. Analysis of a Wnt reporter mouse model and different Wnt target genes showed that the Wnt signaling pathway is involved in oviductal epithelial homoeostasis. By developing two triple transgenic mouse models, we showed that Wnt/β-catenin signaling is essential for self-renewal as well as differentiation of secretory cells. In summary, our results provide mechanistic insight into oviductal epithelial homoeostasis.

The retrotrapezoid nucleus (RTN) consists, by definition, of Phox2b-expressing, glutamatergic, non-catecholaminergic, non-cholinergic neurons located in the parafacial region of the medulla oblongata. An unknown proportion of RTN neurons are central respiratory chemoreceptors and there is mounting evidence for biochemical diversity among these cells. Here, we used multiplexed in situ hybridization and single-cell RNA-Seq in male and female mice to provide a more comprehensive view of the phenotypic diversity of RTN neurons. We now demonstrate that the RTN of mice can be identified with a single and specific marker, Nmb mRNA. Most (∼75%) RTN neurons express low-to-moderate levels of Nmb and display chemoreceptor properties. Namely they are activated by hypercapnia, but not by hypoxia, and express proton sensors, Kcnk5 and Gpr4 These Nmb-low RTN neurons also express varying levels of transcripts for Gal, Penk and Adcyap1,and receptors for substance P, orexin, serotonin and ATP. A subset of RTN neurons (∼20-25%), typically larger than average, express very high levels of Nmb mRNA. These Nmb-high RTN neurons do not express Fos after hypercapnia, have low-to-undetectable levels of Kcnk5 or Gpr4 transcripts; they also express Adcyap1, but are essentially devoid of Penk and Gal transcripts. In male rats, Nmb is also a marker of the RTN but, unlike in mice, this gene is expressed by other types of nearby neurons located within the ventromedial medulla. In sum, Nmb is a selective marker of the RTN in rodents; Nmb-low neurons, the vast majority, are central respiratory chemoreceptors whereas Nmb-high neurons likely have other functions.SIGNIFICANCE STATEMENTCentral respiratory chemoreceptors regulate arterial PCO2 by adjusting lung ventilation. Such cells have recently been identified within the retrotrapezoid nucleus (RTN), a brainstem nucleus defined by genetic lineage and a cumbersome combination of markers. Using single-cell RNA-Seq and multiplexed in situ hybridization, we show here that a single marker, Neuromedin B mRNA (Nmb), identifies RTN neurons in rodents. We also suggest that >75% of these Nmb neurons are chemoreceptors because they are strongly activated by hypercapnia and express high levels of proton sensors (Kcnk5 and Gpr4). The other RTN neurons express very high levels of Nmb, but low levels of Kcnk5/Gpr4/pre-pro-galanin/pre-pro-enkephalin, and do not respond to hypercapnia. Their function is unknown.

The ventral pallidum (VP) is a critical component of the basal ganglia neurocircuitry regulating learning and decision making; however, its precise role in controlling associative learning of environmental stimuli conditioned to appetitive or aversive outcomes is still unclear. Here, we investigated the expression of preproenkephalin, a polypeptide hormone previously shown to be expressed in nucleus accumbens neurons controlling aversive learning, within GABAergic and glutamatergic VP neurons. Next, we explored the behavioral consequences of chemicogenetic inhibition or excitation of preproenkephalin-expressing VP neurons on associative learning of reward- or aversion-paired stimuli in autoshaping and inhibitory avoidance tasks, respectively. We reveal for the first time that preproenkephalin is expressed predominantly in GABAergic rather than glutamatergic VP neurons, and that excitation of these preproenkephalin-expressing VP neurons was sufficient to impair inhibitory avoidance learning. These findings indicate the necessity for inhibition of preproenkephalin-expressing VP neurons for avoidance learning, and suggest these neurons as a potential therapeutic target for psychiatric disorders associated with maladaptive aversive learning.

Sparse populations of neurons in the dentate gyrus (DG) of the hippocampus are causally implicated in the encoding of contextual fear memories. However, engram-specific molecular mechanisms underlying memory consolidation remain largely unknown. Here we perform unbiased RNA sequencing of DG engram neurons 24 h after contextual fear conditioning to identify transcriptome changes specific to memory consolidation. DG engram neurons exhibit a highly distinct pattern of gene expression, in which CREB-dependent transcription features prominently (P = 6.2 × 10-13), including Atf3 (P = 2.4 × 10-41), Penk (P = 1.3 × 10-15), and Kcnq3 (P = 3.1 × 10-12). Moreover, we validate the functional relevance of the RNAseq findings by establishing the causal requirement of intact CREB function specifically within the DG engram during memory consolidation, and identify a novel group of CREB target genes involved in the encoding of long-term memory