Enkephalin release from VIP interneurons in the hippocampal CA2/3a region mediates heterosynaptic plasticity and social memory

Molecular psychiatry

2021 May 14

Leroy, F;de Solis, CA;Boyle, LM;Bock, T;Lofaro, OM;Buss, EW;Asok, A;Kandel, ER;Siegelbaum, SA;
PMID: 33990774 | DOI: 10.1038/s41380-021-01124-y

The hippocampus contains a diverse array of inhibitory interneurons that gate information flow through local cortico-hippocampal circuits to regulate memory storage. Although most studies of interneurons have focused on their role in fast synaptic inhibition mediated by GABA release, different classes of interneurons express unique sets of neuropeptides, many of which have been shown to exert powerful effects on neuronal function and memory when applied pharmacologically. However, relatively little is known about whether and how release of endogenous neuropeptides from inhibitory cells contributes to their behavioral role in regulating memory formation. Here we report that vasoactive intestinal peptide (VIP)-expressing interneurons participate in social memory storage by enhancing information transfer from hippocampal CA3 pyramidal neurons to CA2 pyramidal neurons. Notably, this action depends on release of the neuropeptide enkephalin from VIP neurons, causing long-term depression of feedforward inhibition onto CA2 pyramidal cells. Moreover, VIP neuron activity in the CA2 region is increased selectively during exploration of a novel conspecific. Our findings, thus, enhance our appreciation of how GABAergic neurons can regulate synaptic plasticity and mnemonic behavior by demonstrating that such actions can be mediated by release of a specific neuropeptide, rather than through classic fast inhibitory transmission.

Post-mortem molecular investigations of SARS-CoV-2 in an unexpected death of a recent kidney transplant recipient

American journal of transplantation : official journal of the American Society of Transplantation and the American Society of Transplant Surgeons

2021 Feb 24

Simms, EL;Chung, H;Oberding, L;Muruve, D;McDonald, B;Bromley, A;Pillai, DR;Chun, J;
PMID: 33624432 | DOI: 10.1111/ajt.16549

Solid organ transplant recipients are vulnerable to severe infection during induction therapy. We report a case of a 67-year-old male who died unexpectedly 10 days after receiving a kidney transplant on February 10, 2020. There was no clear cause of death, but COVID-19 was considered retrospectively, as the death occurred shortly after the first confirmed case of COVID-19 in Canada. We confirmed the presence of SARS-CoV-2 components in the renal allograft and native lung tissue using immunohistochemistry for SARS-CoV-2 spike protein and RNA scope in situ hybridization for SARS-CoV-2 RNA. Results were reaffirmed with the Food and Drug Administration Emergency Use Authorization approved Bio-Rad SARS-CoV-2 digital droplet PCR for the kidney specimen. Our case highlights the importance of patient autopsies in an unfolding global pandemic and demonstrates the utility of molecular assays to diagnose SARS-CoV-2 post-mortem. SARS-CoV-2 infection during induction therapy may portend a fatal clinical outcome. We also suggest COVID-19 may be transmittable via renal transplant. This article is protected by

IGF2R circular RNA hsa_circ_0131235 expression in the middle temporal cortex is associated with AD pathology

Brain and behavior

2021 Mar 11

Bigarré, IM;Trombetta, BA;Guo, YJ;Arnold, SE;Carlyle, BC;
PMID: 33704916 | DOI: 10.1002/brb3.2048

To identify circular RNAs as candidates for differential expression in the middle temporal (MT) cortex in a well-characterized cohort with contrasting Alzheimer disease (AD) pathology and cognition. Top screen candidates were assessed for proof of circularity and then quantified by qPCR in a larger number of samples. An initial RNA sequencing screen was performed on n = 20 frozen human tissue samples. Filters were applied to select candidate circular RNAs for further investigation. Frozen human tissue samples were selected for global AD pathology burden and global cognition scores (n = 100). Linear and divergent primers were used to assess circularity using RNaseR digestion. RT-qPCR was performed to quantify relative hsa_circ_0131235 abundance. Eleven circular RNAs were selected for further investigation. Four candidates produced circular RNA primers with appropriate efficiencies for qPCR. RNaseR treatment and analysis by both basic PCR and qPCR confirmed hsa_circ_0131235 circularity. There was a significant main effect of AD pathology on hsa_circ_0131235 expression. Elevated hsa_circ_0131235 expression in the MT cortex was significantly associated with AD pathology.

Evidence That Agouti-Related Peptide May Directly Regulate Kisspeptin Neurons in Male Sheep

Metabolites

2021 Feb 26

Merkley, CM;Shuping, SL;Sommer, JR;Nestor, CC;
PMID: 33652696 | DOI: 10.3390/metabo11030138

Agouti-related peptide (AgRP) neurons, which relay information from peripheral metabolic signals, may constitute a key central regulator of reproduction. Given that AgRP inhibits luteinizing hormone (LH) secretion and that nutritional suppression of LH elicits an increase in AgRP while suppressing kisspeptin expression in the arcuate nucleus (ARC) of the hypothalamus, we sought to examine the degree to which AgRP could directly regulate ARC kisspeptin neurons. Hypothalamic tissue was collected from four castrated male sheep (10 months of age) and processed for the detection of protein (AgRP input to kisspeptin neurons) using immunohistochemistry and mRNA for melanocortin 3 and 4 receptors (MC3R; MC4R) in kisspeptin neurons using RNAscope. Immunohistochemical analysis revealed that the majority of ARC kisspeptin neurons are contacted by presumptive AgRP terminals. RNAscope analysis revealed that nearly two thirds of the ARC kisspeptin neurons express mRNA for MC3R, while a small percentage (<10%) colocalize MC4R. Taken together, this data provides neuroanatomical evidence for a direct link between orexigenic AgRP neurons and reproductively critical kisspeptin neurons in the sheep, and builds upon our current understanding of the central link between energy balance and reproduction.

Excitatory neuronal CHD8 in the regulation of neocortical development and sensory-motor behaviors

Cell reports

2021 Feb 23

Kweon, H;Jung, WB;Im, GH;Ryoo, J;Lee, JH;Do, H;Choi, Y;Song, YH;Jung, H;Park, H;Qiu, LR;Ellegood, J;Shim, HJ;Yang, E;Kim, H;Lerch, JP;Lee, SH;Chung, WS;Kim, D;Kim, SG;Kim, E;
PMID: 33626347 | DOI: 10.1016/j.celrep.2021.108780

CHD8 (chromodomain helicase DNA-binding protein 8) is a chromatin remodeler associated with autism spectrum disorders. Homozygous Chd8 deletion in mice leads to embryonic lethality, making it difficult to assess whether CHD8 regulates brain development and whether CHD8 haploinsufficiency-related macrocephaly reflects normal CHD8 functions. Here, we report that homozygous conditional knockout of Chd8 restricted to neocortical glutamatergic neurons causes apoptosis-dependent near-complete elimination of neocortical structures. These mice, however, display normal survival and hyperactivity, anxiolytic-like behavior, and increased social interaction. They also show largely normal auditory function and moderately impaired visual and motor functions but enhanced whisker-related somatosensory function. These changes accompany thalamic hyperactivity, revealed by 15.2-Tesla fMRI, and increased intrinsic excitability and decreased inhibitory synaptic transmission in thalamic ventral posterior medial (VPM) neurons involved in somatosensation. These results suggest that excitatory neuronal CHD8 critically regulates neocortical development through anti-apoptotic mechanisms, neocortical elimination distinctly affects cognitive behaviors and sensory-motor functions in mice, and Chd8 haploinsufficiency-related macrocephaly might represent compensatory responses.

AKT3 Expression in Mesenchymal Colorectal Cancer Cells Drives Growth and Is Associated with Epithelial-Mesenchymal Transition

Cancers

2021 Feb 14

Buikhuisen, JY;Gomez Barila, PM;Torang, A;Dekker, D;de Jong, JH;Cameron, K;Vitale, S;Stassi, G;van Hooff, SR;Castro, MAA;Vermeulen, L;Medema, JP;
PMID: 33673003 | DOI: 10.3390/cancers13040801

Colorectal cancer (CRC) is a heterogeneous disease that can currently be subdivided into four distinct consensus molecular subtypes (CMS) based on gene expression profiling. The CMS4 subtype is marked by high expression of mesenchymal genes and is associated with a worse overall prognosis compared to other CMSs. Importantly, this subtype responds poorly to the standard therapies currently used to treat CRC. We set out to explore what regulatory signalling networks underlie the CMS4 phenotype of cancer cells, specifically, by analysing which kinases were more highly expressed in this subtype compared to others. We found AKT3 to be expressed in the cancer cell epithelium of CRC specimens, patient derived xenograft (PDX) models and in (primary) cell cultures representing CMS4. Importantly, chemical inhibition or knockout of this gene hampers outgrowth of this subtype, as AKT3 controls expression of the cell cycle regulator p27KIP1. Furthermore, high AKT3 expression was associated with high expression of epithelial-mesenchymal transition (EMT) genes, and this observation could be expanded to cell lines representing other carcinoma types. More importantly, this association allowed for the identification of CRC patients with a high propensity to metastasise and an associated poor prognosis. High AKT3 expression in the tumour epithelial compartment may thus be used as a surrogate marker for EMT and may allow for a selection of CRC patients that could benefit from AKT3-targeted therapy.

Inhibitory CD161 receptor identified in glioma-infiltrating T cells by single-cell analysis

Cell

2021 Feb 10

Mathewson, ND;Ashenberg, O;Tirosh, I;Gritsch, S;Perez, EM;Marx, S;Jerby-Arnon, L;Chanoch-Myers, R;Hara, T;Richman, AR;Ito, Y;Pyrdol, J;Friedrich, M;Schumann, K;Poitras, MJ;Gokhale, PC;Gonzalez Castro, LN;Shore, ME;Hebert, CM;Shaw, B;Cahill, HL;Drummond, M;Zhang, W;Olawoyin, O;Wakimoto, H;Rozenblatt-Rosen, O;Brastianos, PK;Liu, XS;Jones, PS;Cahill, DP;Frosch, MP;Louis, DN;Freeman, GJ;Ligon, KL;Marson, A;Chiocca, EA;Reardon, DA;Regev, A;Suvà, ML;Wucherpfennig, KW;
PMID: 33592174 | DOI: 10.1016/j.cell.2021.01.022

T cells are critical effectors of cancer immunotherapies, but little is known about their gene expression programs in diffuse gliomas. Here, we leverage single-cell RNA sequencing (RNA-seq) to chart the gene expression and clonal landscape of tumor-infiltrating T cells across 31 patients with isocitrate dehydrogenase (IDH) wild-type glioblastoma and IDH mutant glioma. We identify potential effectors of anti-tumor immunity in subsets of T cells that co-express cytotoxic programs and several natural killer (NK) cell genes. Analysis of clonally expanded tumor-infiltrating T cells further identifies the NK gene KLRB1 (encoding CD161) as a candidate inhibitory receptor. Accordingly, genetic inactivation of KLRB1 or antibody-mediated CD161 blockade enhances T cell-mediated killing of glioma cells in vitro and their anti-tumor function in vivo. KLRB1 and its associated transcriptional program are also expressed by substantial T cell populations in other human cancers. Our work provides an atlas of T cells in gliomas and highlights CD161 and other NK cell receptors as immunotherapy targets.

TRPM4 mediates a subthreshold membrane potential oscillation in respiratory chemoreceptor neurons that drives pacemaker firing and breathing

Cell reports

2021 Feb 02

Li, K;Abbott, SBG;Shi, Y;Eggan, P;Gonye, EC;Bayliss, DA;
PMID: 33535052 | DOI: 10.1016/j.celrep.2021.108714

Brainstem networks that control regular tidal breathing depend on excitatory drive, including from tonically active, CO2/H+-sensitive neurons of the retrotrapezoid nucleus (RTN). Here, we examine intrinsic ionic mechanisms underlying the metronomic firing activity characteristic of RTN neurons. In mouse brainstem slices, large-amplitude membrane potential oscillations are evident in synaptically isolated RTN neurons after blocking action potentials. The voltage-dependent oscillations are abolished by sodium replacement; blocking calcium channels (primarily L-type); chelating intracellular Ca2+; and inhibiting TRPM4, a Ca2+-dependent cationic channel. Likewise, oscillation voltage waveform currents are sensitive to calcium and TRPM4 channel blockers. Extracellular acidification and serotonin (5-HT) evoke membrane depolarization that augments TRPM4-dependent oscillatory activity and action potential discharge. Finally, inhibition of TRPM4 channels in the RTN of anesthetized mice reduces central respiratory output. These data implicate TRPM4 in a subthreshold oscillation that supports the pacemaker-like firing of RTN neurons required for basal, CO2-stimulated, and state-dependent breathing.

Molecular characterization of the human kidney interstitium in health and disease

Science advances

2021 Feb 01

Barwinska, D;El-Achkar, TM;Ferreira, RM;Syed, F;Cheng, YH;Winfree, S;Ferkowicz, MJ;Hato, T;Collins, KS;Dunn, KW;Kelly, KJ;Sutton, TA;Rovin, BH;Parikh, SV;Phillips, CL;Dagher, PC;Eadon, MT;Kidney Precision Medicine Project, ;
PMID: 33568476 | DOI: 10.1126/sciadv.abd3359

The gene expression signature of the human kidney interstitium is incompletely understood. The cortical interstitium (excluding tubules, glomeruli, and vessels) in reference nephrectomies (N = 9) and diabetic kidney biopsy specimens (N = 6) was laser microdissected (LMD) and sequenced. Samples underwent RNA sequencing. Gene signatures were deconvolved using single nuclear RNA sequencing (snRNAseq) data derived from overlapping specimens. Interstitial LMD transcriptomics uncovered previously unidentified markers including KISS1, validated with in situ hybridization. LMD transcriptomics and snRNAseq revealed strong correlation of gene expression within corresponding kidney regions. Relevant enriched interstitial pathways included G-protein coupled receptor. binding and collagen biosynthesis. The diabetic interstitium was enriched for extracellular matrix organization and small-molecule catabolism. Cell type markers with unchanged expression (NOTCH3, EGFR, and HEG1) and those down-regulated in diabetic nephropathy (MYH11, LUM, and CCDC3) were identified. LMD transcriptomics complements snRNAseq; together, they facilitate mapping of interstitial marker genes to aid interpretation of pathophysiology in precision medicine studies.

Mesencephalic Electrical Stimulation Reduces Neuroinflammation after Photothrombotic Stroke in Rats by Targeting the Cholinergic Anti-Inflammatory Pathway

International journal of molecular sciences

2021 Jan 27

Schuhmann, MK;Papp, L;Stoll, G;Blum, R;Volkmann, J;Fluri, F;
PMID: 33514001 | DOI: 10.3390/ijms22031254

Inflammation is crucial in the pathophysiology of stroke and thus a promising therapeutic target. High-frequency stimulation (HFS) of the mesencephalic locomotor region (MLR) reduces perilesional inflammation after photothrombotic stroke (PTS). However, the underlying mechanism is not completely understood. Since distinct neural and immune cells respond to electrical stimulation by releasing acetylcholine, we hypothesize that HFS might trigger the cholinergic anti-inflammatory pathway via activation of the α7 nicotinic acetylcholine receptor (α7nAchR). To test this hypothesis, rats underwent PTS and implantation of a microelectrode into the MLR. Three hours after intervention, either HFS or sham-stimulation of the MLR was applied for 24 h. IFN-γ, TNF-α, and IL-1α were quantified by cytometric bead array. Choline acetyltransferase (ChAT)+ CD4+-cells and α7nAchR+-cells were quantified visually using immunohistochemistry. Phosphorylation of NFĸB, ERK1/2, Akt, and Stat3 was determined by Western blot analyses. IFN-γ, TNF-α, and IL-1α were decreased in the perilesional area of stimulated rats compared to controls. The number of ChAT+ CD4+-cells increased after MLR-HFS, whereas the amount of α7nAchR+-cells was similar in both groups. Phospho-ERK1/2 was reduced significantly in stimulated rats. The present study suggests that MLR-HFS may trigger anti-inflammatory processes within the perilesional area by modulating the cholinergic system, probably via activation of the α7nAchR.

Histamine H2 receptor negatively regulates oligodendrocyte differentiation in neonatal hypoxic-ischemic white matter injury

J Exp Med

2021 Jan 04

Jiang, L;Cheng, L;Chen, H;Dai, H;An, D;Ma, Q;Zheng, Y;Zhang, X;Hu, W;Chen, Z;
PMID: 32991666 | DOI: 10.1084/jem.20191365

Neonatal hypoxic-ischemic encephalopathy (HIE) with the pathological characteristic of white matter injury often leads to lifelong cognitive and neurobehavioral dysfunction, but relevant therapies to promote remyelination are still unavailable. We found that histamine H2 receptor (H2R) negatively regulated the oligodendrocyte differentiation rate without affecting the oligodendrocytes at the oligodendrocyte precursor cell stage or mature stage following oxygen-glucose deprivation in vitro. Notably, selective deletion of the H2R gene (Hrh2) in differentiating oligodendrocytes (Hrh2fl/fl;CNPase-Cre) improved their differentiation, remyelination, and functional recovery following neonatal hypoxia-ischemia in mice. The regulation of oligodendrocyte differentiation by H2R is mediated by binding with Axin2, which leads to up-regulation of the Wnt/β-catenin signaling pathway. Furthermore, H2R antagonists also promoted oligodendrocyte differentiation and remyelination and the recovery of cognition and motor functions following neonatal hypoxia-ischemia. Thus, histamine H2R in oligodendrocytes could serve as a novel and effective therapeutic target for the retard of oligodendrocyte differentiation and remyelination following neonatal hypoxia-ischemia. The H2R antagonists may have potential therapeutic value for neonatal HIE.

Fibronectin extra domain A (FN-EDA) causes glaucomatous trabecular meshwork and optic nerve head damage in mice

Investigative Ophthalmology & Visual Science

2021 Jan 01

McDowell, CM;Mavlyutov, T;

Purpose : Elevated intraocular pressure (IOP) is a major risk factor for the development and progression of primary open angle glaucoma and is due to trabecular meshwork (TM) damage. We investigated the role of an endogenous Toll-like receptor 4 (TLR4) ligand, FN-EDA, in the development of glaucoma utilizing a transgenic mouse strain (B6.EDA+/+) that constitutively expresses only FN containing the EDA isoform. Methods : Eyes (n=3/strain) were processed for electron microscopy, polymerized in EPON, ultrathin sections (80 nm) were cut and placed on formvar coated slot grids, and poststained with uranyl acetate and lead citrate. Consecutive images of the entire TM area spanning from anterior to posterior parts of Schlemm’s canal (SC) were collected at 2500x and montaged into a single image. ECM accumulation and basement membrane thickness were quantified by ImageJ analysis. TLR4 expression in ONH cells was conducted using RNAscope in situ hybridization and immunohistochemistry protocols (n=3 eyes/strain). IOP was measured using a rebound tonometer and ON damage assessed by PPD stain (n=20-22 eyes/strain). Results : Ultrastructure analyses show the TM of B6.EDA+/+ mice have significantly increased accumulation of ECM between the TM beams with few empty spaces compared to C57BL/6J control mice (P

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	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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