RSPO3 expands intestinal stem cell and niche compartments and drives tumorigenesis.

Gut.

2016 Aug 10

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.

Drd3 Signaling in the Lateral Septum Mediates Early Life Stress-Induced Social Dysfunction

Neuron.

2017 Dec 14

Shin S, Pribiag H, Lilascharoen V, Knowland D, Wang XY, Lim BK.
PMID: 29276054 | DOI: 10.1016/j.neuron.2017.11.040

Early life stress (ELS) in the form of child abuse/neglect is associated with an increased risk of developing social dysfunction in adulthood. Little is known, however, about the neural substrates or the neuromodulatory signaling that govern ELS-induced social dysfunction. Here, we show that ELS-induced downregulation of dopamine receptor 3 (Drd3) signaling and its corresponding effects on neural activity in the lateral septum (LS) are both necessary and sufficient to cause social abnormalities in adulthood. Using in vivo Ca2+ imaging, we found that Drd3-expressing-LS (Drd3LS) neurons in animals exposed to ELS show blunted activity in response to social stimuli. In addition, optogenetic activation of Drd3LS neurons rescues ELS-induced social impairments. Furthermore, pharmacological treatment with a Drd3 agonist, which increases Drd3LS neuronal activity, normalizes the social dysfunctions of ELS mice. Thus, we identify Drd3 in the LS as a critical mediator and potential therapeutic target for the social abnormalities caused by ELS.

Cerebellar dopamine D2 receptors regulate social behaviors

Nature neuroscience

2022 Jun 16

Cutando, L;Puighermanal, E;Castell, L;Tarot, P;Belle, M;Bertaso, F;Arango-Lievano, M;Ango, F;Rubinstein, M;Quintana, A;Chédotal, A;Mameli, M;Valjent, E;
PMID: 35710984 | DOI: 10.1038/s41593-022-01092-8

The cerebellum, a primary brain structure involved in the control of sensorimotor tasks, also contributes to higher cognitive functions including reward, emotion and social interaction. Although the regulation of these behaviors has been largely ascribed to the monoaminergic system in limbic regions, the contribution of cerebellar dopamine signaling in the modulation of these functions remains largely unknown. By combining cell-type-specific transcriptomics, histological analyses, three-dimensional imaging and patch-clamp recordings, we demonstrate that cerebellar dopamine D2 receptors (D2Rs) in mice are preferentially expressed in Purkinje cells (PCs) and regulate synaptic efficacy onto PCs. Moreover, we found that changes in D2R levels in PCs of male mice during adulthood alter sociability and preference for social novelty without affecting motor functions. Altogether, these findings demonstrate novel roles for D2R in PC function and causally link cerebellar D2R levels of expression to social behaviors.

Ventral pallidum DRD3 potentiates a pallido-habenular circuit driving accumbal dopamine release and cocaine seeking

Neuron

2021 May 21

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.

Visualization and targeting of LGR5+ human colon cancer stem cells.

Nature

2017 May 11

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.

LAT1 expression influences Paneth cell number and tumor development in ApcMin/+ mice

Journal of gastroenterology

2023 Feb 05

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.

	Description
sense Example: Hs-LAG3-sense	Standard probes for RNA detection are in antisense. Sense probe is reverse complent to the corresponding antisense probe.
Intron# Example: Mm-Htt-intron2	Probe targets the indicated intron in the target gene, commonly used for pre-mRNA detection
Pool/Pan Example: Hs-CD3-pool (Hs-CD3D, Hs-CD3E, Hs-CD3G)	A mixture of multiple probe sets targeting multiple genes or transcripts
No-XSp Example: Hs-PDGFB-No-XMm	Does not cross detect with the species (Sp)
XSp Example: Rn-Pde9a-XMm	designed to cross detect with the species (Sp)
O# Example: Mm-Islr-O1	Alternative design targeting different regions of the same transcript or isoforms
CDS Example: Hs-SLC31A-CDS	Probe targets the protein-coding sequence only
EnEm	Probe targets exons n and m
En-Em	Probe targets region from exon n to exon m
Retired Nomenclature
tvn Example: Hs-LEPR-tv1	Designed to target transcript variant n
ORF Example: Hs-ACVRL1-ORF	Probe targets open reading frame
UTR Example: Hs-HTT-UTR-C3	Probe targets the untranslated region (non-protein-coding region) only
5UTR Example: Hs-GNRHR-5UTR	Probe targets the 5' untranslated region only
3UTR Example: Rn-Npy1r-3UTR	Probe targets the 3' untranslated region only
Pan Example: Pool	A mixture of multiple probe sets targeting multiple genes or transcripts

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Advanced Cell Diagnostics

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