Hilkens J, Timmer NC, Boer M, Ikink GJ, Schewe M, Sacchetti A, Koppens MA, Song JY, Bakker ER.
PMID: 27511199 | DOI: 10.1136/gutjnl-2016-311606
Abstract
OBJECTIVE:
The gross majority of colorectal cancer cases results from aberrant Wnt/β-catenin signalling through adenomatous polyposis coli (APC) or CTNNB1 mutations. However, a subset of human colon tumours harbour, mutually exclusive with APC and CTNNB1 mutations, gene fusions in RSPO2 or RSPO3, leading to enhanced expression of these R-spondin genes. This suggested that RSPO activation can substitute for the most common mutations as an alternative driver for intestinal cancer. Involvement of RSPO3 in tumour growth was recently shown in RSPO3-fusion-positive xenograft models. The current study determines the extent into which solely a gain in RSPO3 actually functions as a driver of intestinal cancer in a direct, causal fashion, and addresses the in vivo activities of RSPO3 in parallel.
DESIGN:
We generated a conditional Rspo3 transgenic mouse model in which the Rspo3 transgene is expressed upon Cre activity. Cre is provided by cross-breeding with Lgr5-GFP-CreERT2 mice.
RESULTS:
Upon in vivo Rspo3 expression, mice rapidly developed extensive hyperplastic, adenomatous and adenocarcinomatous lesions throughout the intestine. RSPO3 induced the expansion of Lgr5+ stem cells, Paneth cells, non-Paneth cell label-retaining cells and Lgr4+ cells, thus promoting both intestinal stem cell and niche compartments. Wnt/β-catenin signalling was modestly increased upon Rspo3 expression and mutant Kras synergised with Rspo3 in hyperplastic growth.
CONCLUSIONS:
We provide in vivo evidence that RSPO3 stimulates the crypt stem cell and niche compartments and drives rapid intestinal tumorigenesis. This establishes RSPO3 as a potent driver of intestinal cancer and proposes RSPO3 as a candidate target for therapy in patients with colorectal cancer harbouring RSPO3 fusions.
Hou XH, Hyun M, Taranda J, Huang KW, Todd E, Feng D, Atwater E, Croney D, Zeidel ML, Osten P, Sabatini BL.
PMID: 27662084 | DOI: 10.1016/j.cell.2016.08.073
Urine release (micturition) serves an essential physiological function as well as a critical role in social communication in many animals. Here, we show a combined effect of olfaction and social hierarchy on micturition patterns in adult male mice, confirming the existence of a micturition control center that integrates pro- and anti-micturition cues. Furthermore, we demonstrate that a cluster of neurons expressing corticotropin-releasing hormone (Crh) in the pontine micturition center (PMC) is electrophysiologically distinct from their Crh-negative neighbors and sends glutamatergic projections to the spinal cord. The activity of PMC Crh-expressing neurons correlates with and is sufficient to drive bladder contraction, and when silenced impairs micturition behavior. These neurons receive convergent input from widespread higher brain areas that are capable of carrying diverse pro- and anti-micturition signals, and whose activity modulates hierarchy-dependent micturition. Taken together, our results indicate that PMC Crh-expressing neurons are likely the integration center for context-dependent micturition behavior.
Wallace ML, Huang KW, Hochbaum D, Hyun M, Radeljic G, Sabatini BL
PMID: 32043968 | DOI: 10.7554/eLife.51271
The lateral habenula (LHb) is an epithalamic brain structure critical for processing and adapting to negative action outcomes. However, despite the importance of LHb to behavior and the clear anatomical and molecular diversity of LHb neurons, the neuron types of the habenula remain unknown. Here, we use high-throughput single-cell transcriptional profiling, monosynaptic retrograde tracing, and multiplexed FISH to characterize the cells of the mouse habenula. We find five subtypes of neurons in the medial habenula (MHb) that are organized into anatomical subregions. In the LHb, we describe four neuronal subtypes and show that they differentially target dopaminergic and GABAergic cells in the ventral tegmental area (VTA). These data provide a valuable resource for future study of habenular function and dysfunction and demonstrate neuronal subtype specificity in the LHb-VTA circuit
Yao, Y;Barger, Z;Saffari Doost, M;Tso, CF;Darmohray, D;Silverman, D;Liu, D;Ma, C;Cetin, A;Yao, S;Zeng, H;Dan, Y;
PMID: 36170850 | DOI: 10.1016/j.neuron.2022.08.027
Sleep disturbances are strongly associated with cardiovascular diseases. Baroreflex, a basic cardiovascular regulation mechanism, is modulated by sleep-wake states. Here, we show that neurons at key stages of baroreflex pathways also promote sleep. Using activity-dependent genetic labeling, we tagged neurons in the nucleus of the solitary tract (NST) activated by blood pressure elevation and confirmed their barosensitivity with optrode recording and calcium imaging. Chemogenetic or optogenetic activation of these neurons promoted non-REM sleep in addition to decreasing blood pressure and heart rate. GABAergic neurons in the caudal ventrolateral medulla (CVLM)-a downstream target of the NST for vasomotor baroreflex-also promote non-REM sleep, partly by inhibiting the sympathoexcitatory and wake-promoting adrenergic neurons in the rostral ventrolateral medulla (RVLM). Cholinergic neurons in the nucleus ambiguous-a target of the NST for cardiac baroreflex-promoted non-REM sleep as well. Thus, key components of the cardiovascular baroreflex circuit are also integral to sleep-wake brain-state regulation.
Ito, N;Takatsu, A;Ito, H;Koike, Y;Yoshioka, K;Kamei, Y;Imai, SI;
PMID: 35905718 | DOI: 10.1016/j.celrep.2022.111131
Sarcopenia and frailty are urgent socio-economic problems worldwide. Here we demonstrate a functional connection between the lateral hypothalamus (LH) and skeletal muscle through Slc12a8, a recently identified nicotinamide mononucleotide transporter, and its relationship to sarcopenia and frailty. Slc12a8-expressing cells are mainly localized in the LH. LH-specific knockdown of Slc12a8 in young mice decreases activity-dependent energy and carbohydrate expenditure and skeletal muscle functions, including muscle mass, muscle force, intramuscular glycolysis, and protein synthesis. LH-specific Slc12a8 knockdown also decreases sympathetic nerve signals at neuromuscular junctions and β2-adrenergic receptors in skeletal muscle, indicating the importance of the LH-sympathetic nerve-β2-adrenergic receptor axis. LH-specific overexpression of Slc12a8 in aged mice significantly ameliorates age-associated decreases in energy expenditure and skeletal muscle functions. Our results highlight an important role of Slc12a8 in the LH for regulation of whole-body metabolism and skeletal muscle functions and provide insights into the pathogenesis of sarcopenia and frailty during aging.
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.
Shimokawa M, Ohta Y, Nishikori S, Matano M, Takano A, Fujii M, Date S, Sugimoto S, Kanai T, Sato T.
PMID: 28355176 | DOI: 10.1038/nature22081
The cancer stem cell (CSC) theory highlights a self-renewing subpopulation of cancer cells that fuels tumour growth. The existence of human CSCs is mainly supported by xenotransplantation of prospectively isolated cells, but their clonal dynamics and plasticity remain unclear. Here, we show that human LGR5+ colorectal cancer cells serve as CSCs in growing cancer tissues. Lineage-tracing experiments with a tamoxifen-inducible Cre knock-in allele of LGR5 reveal the self-renewal and differentiation capacity of LGR5+ tumour cells. Selective ablation of LGR5+CSCs in LGR5-iCaspase9 knock-in organoids leads to tumour regression, followed by tumour regrowth driven by re-emerging LGR5+ CSCs. KRT20 knock-in reporter marks differentiated cancer cells that constantly diminish in tumour tissues, while reverting to LGR5+ CSCs and contributing to tumour regrowth after LGR5+ CSC ablation. We also show that combined chemotherapy potentiates targeting of LGR5+CSCs. These data provide insights into the plasticity of CSCs and their potential as a therapeutic target in human colorectal cancer.
Xu, J;Jo, A;DeVries, RP;Deniz, S;Cherian, S;Sunmola, I;Song, X;Marshall, JJ;Gruner, KA;Daigle, TL;Contractor, A;Lerner, TN;Zeng, H;Zhu, Y;
PMID: 35793636 | DOI: 10.1016/j.celrep.2022.111036
Recent developments in intersectional strategies have greatly advanced our ability to precisely target brain cell types based on unique co-expression patterns. To accelerate the application of intersectional genetics, we perform a brain-wide characterization of 13 Flp and tTA mouse driver lines and selected seven for further analysis based on expression of vesicular neurotransmitter transporters. Using selective Cre driver lines, we created more than 10 Cre/tTA combinational lines for cell type targeting and circuit analysis. We then used VGLUT-Cre/VGAT-Flp combinational lines to identify and map 30 brain regions containing neurons that co-express vesicular glutamate and gamma-aminobutyric acid (GABA) transporters, followed by tracing their projections with intersectional viral vectors. Focusing on the lateral habenula (LHb) as a target, we identified glutamatergic, GABAergic, or co-glutamatergic/GABAergic innervations from ∼40 brain regions. These data provide an important resource for the future application of intersectional strategies and expand our understanding of the neuronal subtypes in the brain.
Journal of gastroenterology
Sui, Y;Hoshi, N;Ohgaki, R;Kong, L;Yoshida, R;Okamoto, N;Kinoshita, M;Miyazaki, H;Ku, Y;Tokunaga, E;Ito, Y;Watanabe, D;Ooi, M;Shinohara, M;Sasaki, K;Zen, Y;Kotani, T;Matozaki, T;Tian, Z;Kanai, Y;Kodama, Y;
PMID: 36739585 | DOI: 10.1007/s00535-023-01960-5
Amino acid transporters play an important role in supplying nutrition to cells and are associated with cell proliferation. L-type amino acid transporter 1 (LAT1) is highly expressed in many types of cancers and promotes tumor growth; however, how LAT1 affects tumor development is not fully understood.To investigate the role of LAT1 in intestinal tumorigenesis, mice carrying LAT1 floxed alleles that also expressed Cre recombinase from the promoter of gene encoding Villin were crossed to an ApcMin/+ background (LAT1fl/fl; vil-cre; ApcMin/+), which were subject to analysis; organoids derived from those mice were also analyzed.This study showed that LAT1 was constitutively expressed in normal crypt base cells, and its conditional deletion in the intestinal epithelium resulted in fewer Paneth cells. LAT1 deletion reduced tumor size and number in the small intestine of ApcMin/+ mice. Organoids derived from LAT1-deleted ApcMin/+ intestinal crypts displayed fewer spherical organoids with reduced Wnt/β-catenin target gene expression, suggesting a low tumor-initiation capacity. Wnt3 expression was decreased in the absence of LAT1 in the intestinal epithelium, suggesting that loss of Paneth cells due to LAT1 deficiency reduced the risk of tumor initiation by decreasing Wnt3 production.LAT1 affects intestinal tumor development in a cell-extrinsic manner through reduced Wnt3 expression in Paneth cells. Our findings may partly explain how nutrient availability can affect the risk of tumor development in the intestines.