Characterization and mu opioid receptor sensitivity of neuropeptide Y interneurons in the mouse nucleus accumbens

Neuropharmacology

2022 Aug 10

Retzlaff, CL;Rothwell, PE;
PMID: 35963449 | DOI: 10.1016/j.neuropharm.2022.109212

Inhibitory interneurons represent less than 5% of neurons within the nucleus accumbens, but are critical for proper microcircuit function within this brain region. In the dorsal striatum, neuropeptide Y is expressed by two interneuron subtypes (low-threshold spiking interneurons and neurogliaform interneurons) that exhibit mu opioid receptor sensitivity in other brain regions. However, few studies have assessed the molecular and physiological properties of neuropeptide Y interneurons within the nucleus accumbens. We used a transgenic reporter mouse to identify and characterize neuropeptide Y interneurons in acute nucleus accumbens brain slices. Nearly all cells exhibited electrophysiological properties of low-threshold spiking interneurons, with almost no neurogliaform interneurons observed among neuropeptide Y interneurons. We corroborated this pattern using fluorescent in situ hybridization, and also identified a high level of mu opioid receptor expression by low-threshold spiking interneurons, which led us to examine the functional consequences of mu opioid receptor activation in these cells using electrophysiology. Mu opioid receptor activation caused a reduction in the rate of spontaneous action potentials in low-threshold spiking interneurons, as well as a decrease in optogenetically-evoked GABA release onto medium spiny neurons. The latter effect was more robust in female versus male mice, and when the postsynaptic medium spiny neuron expressed the Drd1 dopamine receptor. This work is the first to examine the physiological properties of neuropeptide Y interneurons in the nucleus accumbens, and show they may be an important target for mu opioid receptor modulation by endogenous and exogenous opioids.

Inhibiting Hv1 channel in peripheral sensory neurons attenuates chronic inflammatory pain and opioid side effects

Cell research

2022 Feb 03

Zhang, Q;Ren, Y;Mo, Y;Guo, P;Liao, P;Luo, Y;Mu, J;Chen, Z;Zhang, Y;Li, Y;Yang, L;Liao, D;Fu, J;Shen, J;Huang, W;Xu, X;Guo, Y;Mei, L;Zuo, Y;Liu, J;Yang, H;Jiang, R;
PMID: 35115667 | DOI: 10.1038/s41422-022-00616-y

Both opioids and nonsteroidal anti-inflammatory drugs (NSAIDS) produce deleterious side effects and fail to provide sustained relief in patients with chronic inflammatory pain. Peripheral neuroinflammation (PN) is critical for initiation and development of inflammatory pain. A better understanding of molecular mechanisms underlying PN would facilitate the discovery of new analgesic targets and the development of new therapeutics. Emerging evidence suggests that peripheral sensory neurons are not only responders to painful stimuli, but are also actively engaged in inflammation and immunity, whereas the intrinsic regulatory mechanism is poorly understood. Here we report the expression of proton-selective ion channel Hv1 in peripheral sensory neurons in rodents and humans, which was previously shown as selectively expressed in microglia in mammalian central nervous system. Neuronal Hv1 was up-regulated by PN or depolarizing stimulation, which in turn aggravates inflammation and nociception. Inhibiting neuronal Hv1 genetically or by a newly discovered selective inhibitor YHV98-4 reduced intracellular alkalization and ROS production in inflammatory pain, mitigated the imbalance in downstream SHP-1-pAKT signaling, and also diminished pro-inflammatory chemokine release to alleviate nociception and morphine-induced hyperalgesia and tolerance. Thus, our data reveal neuronal Hv1 as a novel target in analgesia strategy and managing opioids-related side effects.

Age-dependent immune and lymphatic responses after spinal cord injury

Neuron

2023 Apr 28

Salvador, AFM;Dykstra, T;Rustenhoven, J;Gao, W;Blackburn, SM;Bhasiin, K;Dong, MQ;Guimarães, RM;Gonuguntla, S;Smirnov, I;Kipnis, J;Herz, J;
PMID: 37148871 | DOI: 10.1016/j.neuron.2023.04.011

Spinal cord injury (SCI) causes lifelong debilitating conditions. Previous works demonstrated the essential role of the immune system in recovery after SCI. Here, we explored the temporal changes of the response after SCI in young and aged mice in order to characterize multiple immune populations within the mammalian spinal cord. We revealed substantial infiltration of myeloid cells to the spinal cord in young animals, accompanied by changes in the activation state of microglia. In contrast, both processes were blunted in aged mice. Interestingly, we discovered the formation of meningeal lymphatic structures above the lesion site, and their role has not been examined after contusive injury. Our transcriptomic data predicted lymphangiogenic signaling between myeloid cells in the spinal cord and lymphatic endothelial cells (LECs) in the meninges after SCI. Together, our findings delineate how aging affects the immune response following SCI and highlight the participation of the spinal cord meninges in supporting vascular repair.

Advanced analysis and applications of single-cell transcriptome sequencing

All Life

2023 Dec 31

Ruohan, Z;Yicheng, B;Jingying, Z;Mei, H;Xinyan, Z;Min, Y;Tengfei, D;Junjing, J;
| DOI: 10.1080/26895293.2023.2199140

In summary, with the continuous improvement of technology and methods, scRNA-seq is becoming an indispensable tool in many biomedical fields. It is predicted that single-cell multiplex technology will play a more powerful role in single-cell research of complex organs and tissues in the future. It is expected that the demand and application of scRNA-seq technology will increase greatly in the future, and the technology will become more refined, high-throughput, affordable, and easier to use in scientific research laboratories and clinical laboratories. Especially in the new era of precision medicine, the study of the characteristics of high intercellular heterogeneity and clonal evolution in the occurrence, development, and treatment of diseases brings hope for the accurate diagnosis and treatment of diseases. In particular, it can be used to monitor the progress, efficacy, and prognosis of hematological tumors, and is likely to find potential therapeutic targets, providing a basis for accurate diagnosis, dynamic monitoring, and individualized treatment of the disease. More importantly, innovative single-cell technology is expected to greatly promote the effective control of diseases in IVF and early pregnancy screening and diagnosis of chromosomal and genetic diseases by improving the efficiency and detection quality. Thus, scRNA-seq is of great significance to improve human genetic health.

Tbx2 and Tbx3 regulate cell fate progression of the otic vesicle for inner ear development

Developmental biology

2022 Dec 12

Song, H;Morrow, BE;
PMID: 36521641 | DOI: 10.1016/j.ydbio.2022.12.003

The morphogenesis of the otic vesicle (OV) to form inner ear organs serves as an excellent model system to understand cell fate acquisition on a single cell level. Tbx2 and Tbx3 (Tbx2/3) encode closely related T-box transcription factors that are expressed widely in the mammalian OV. Inactivation of both genes in the OV (Tbx2/3cKO) results in failed morphogenesis into inner ear organs. To understand the basis of these defects, single cell RNA-sequencing (scRNA-seq) was performed on the OV lineage, in controls versus Tbx2/3cKO embryos. We identified a multipotent population termed otic progenitors in controls that are marked by expression of the known otic placode markers Eya1, Sox2, and Sox3 as well as new markers Fgf18, Cxcl12, and Pou3f3. The otic progenitor population was increased three-fold in Tbx2/3cKO embryos, concomitant with dysregulation of genes in these cells as well as reduced progression to more differentiated states of prosensory and nonsensory cells. An ectopic neural population of cells was detected in the posterior OV of Tbx2/3cKO embryos but had reduced maturation to delaminated neural cells. As all three cell fates were affected in Tbx2/3cKO embryos, we suggest that Tbx2/3 promotes progression of multipotent otic progenitors to more differentiated cell types in the OV.

Genetic Variants in ARHGEF6 Cause Congenital Anomalies of the Kidneys and Urinary Tract in Humans, Mice, and Frogs

Journal of the American Society of Nephrology : JASN

2022 Nov 22

Klämbt, V;Buerger, F;Wang, C;Naert, T;Richter, K;Nauth, T;Weiss, AC;Sieckmann, T;Lai, E;Connaughton, D;Seltzsam, S;Mann, N;Majmundar, A;Wu, CH;Onuchic-Whitford, A;Shril, S;Schneider, S;Schierbaum, L;Dai, R;Bekheirnia, MR;Joosten, M;Shlomovitz, O;Vivante, A;Banne, E;Mane, S;Lifton, RP;Kirschner, K;Kispert, A;Rosenberger, G;Fischer, KD;Lienkamp, S;Zegers, M;Hildebrandt, F;
PMID: 36414417 | DOI: 10.1681/ASN.2022010050

Background About 40 disease genes have been described to date for isolated congenital anomalies of the kidneys and urinary tract (CAKUT), the most common cause of childhood chronic kidney disease. However, these genes account for only 20% of cases. ARHGEF6, a guanine nucleotide exchange factor that is implicated in such biologic processes as cell migration and focal adhesion, acts downstream of integrin linked kinase (ILK) and parvin proteins. A genetic variant of ILK that causes murine renal agenesis abrogates the interaction of ILK with a murine focal adhesion protein encoded by Parva, leading to CAKUT in mice with this variant. Methods To identify novel genes that, when mutated, result in CAKUT, we performed exome sequencing in an international cohort of 1265 families with CAKUT. We also assessed the effects in vitro of wild-type and mutant ARHGEF6 proteins, as well as the effects of Arhgef6 deficiency in mouse and frog models. Results We detected six different hemizygous variants in the gene ARHGEF6 (which is located on the X chromosome in humans) in eight individuals from six families with CAKUT. In kidney cells, overexpression of wild-type ARHGEF6-but not proband-derived mutant ARHGEF6- increased active levels of CDC42/RAC1, induced lamellipodia formation, and stimulated PARVAdependent cell spreading. ARHGEF6 mutant proteins showed loss of interaction with PARVA. Three-dimensional MDCK cell cultures expressing ARHGEF6 mutant proteins exhibited reduced lumen formation and polarity defects. Arhgef6 deficiency in mouse and frog models recapitulated features of human CAKUT. Conclusions Deleterious variants in ARHGEF6 may cause dysregulation of integrin-parvinRAC1/CDC42 signaling, thereby leading to X-linked CAKUT.

Adaptations in nucleus accumbens neuron subtypes mediate negative affective behaviors in fentanyl abstinence

Biological Psychiatry

2022 Aug 01

Fox, M;Wulff, A;Franco, D;Choi, E;Calarco, C;Engeln, M;Turner, M;Chandra, R;Rhodes, V;Thompson, S;Ament, S;Lobo, M;
| DOI: 10.1016/j.biopsych.2022.08.023

Background Opioid discontinuation generates a withdrawal syndrome marked by increased negative affect. Increased symptoms of anxiety and dysphoria during opioid discontinuation are a significant barrier to achieving long-term abstinence in opioid-dependent individuals. While adaptations in the nucleus accumbens are implicated in the opioid abstinence syndrome, the precise neural mechanisms are poorly understood. Additionally, our current knowledge is limited to changes following natural and semi-synthetic opioids, despite recent increases in synthetic opioid use and overdose. Methods We used a combination of cell subtype specific viral-labeling and electrophysiology in male and female mice to investigate structural and functional plasticity in nucleus accumbens medium spiny neuron (MSNs) subtypes after fentanyl abstinence. We characterized molecular adaptations after fentanyl abstinence with subtype specific RNAseq and Weighted Gene Co-expression Network Analysis. We used viral-mediated gene transfer to manipulate the molecular signature of fentanyl abstinence in D1-MSNs. Results Here we show fentanyl abstinence increases anxiety-like behavior, decreases social interaction, and engenders MSN subtype-specific plasticity in both sexes. D1, but not D2-MSNs exhibit dendritic atrophy and an increase in excitatory drive. We identified a cluster of co-expressed dendritic morphology genes downregulated selectively in D1-MSNs that are transcriptionally co-regulated by E2F1. E2f1 expression in D1-MSNs protects against loss of dendritic complexity, altered physiology, and negative affect-like behaviors caused by fentanyl abstinence. Conclusion Our findings indicate fentanyl abstinence causes unique structural, functional, and molecular changes in nucleus accumbens D1-MSNs that can be targeted to alleviate negative affective symptoms during abstinence.

Awareness of intratumoral bacteria and their potential application in cancer treatment

Discover. Oncology

2023 May 06

Liang, Y;Li, Q;Liu, Y;Guo, Y;Li, Q;
PMID: 37148441 | DOI: 10.1007/s12672-023-00670-x

Hitherto, the recognition of the microbiota role in tumorigenesis and clinical studies mostly focused on the intestinal flora. In contrast to the gut microbiome, microorganisms resident in tumor tissue are in close contact with cancer cells and therefore have the potential to have similar or even different functional patterns to the gut flora. Some investigations have shown intratumoral bacteria, which might come from commensal microbiota in mucosal areas including the gastrointestinal tract and oral cavity, or from nearby normal tissues. The existence, origin, and interactions of intratumoral bacteria with the tumor microenvironment all contribute to intratumoral microorganism heterogeneity. Intratumoral bacteria have a significant role in tumor formation. They can contribute to cancer at the genetic level by secreting poisons that directly damage DNA and also intimately related to immune system response at the systemic level. Intratumoral bacteria have an impact on chemotherapy and immunotherapy in cancer. Importantly, various properties of bacteria such as targeting and ease of modification make them powerful candidates for precision therapy, and combining microbial therapies with other therapies is expected to improve the effectiveness of cancer treatment. In this review, we mainly described the heterogeneity and potential sources of intratumoral bacteria, overviewed the important mechanisms by which they were involved in tumor progression, and summarized their potential value in oncology therapy. At last, we highlight the problems of research in this field, and look forward to a new wave of studies using the various applications of intratumoral microorganisms in cancer therapy.

Enduring Controversial Story in the Human Brain

McGill Science Undergraduate Research Journal

2023 Mar 26

Niu, Z;Capolicchio, T;
| DOI: 10.26443/msurj.v18i1.194

Adult hippocampal neurogenesis (AHN) is a well-studied phenomenon that involves the derivation of new neurons from neural progenitor cells in the dentate gyrus region of the hippocampus, an area responsible for cognitive functions such as learning and memory storage. Moreover, the hippocampus is known to be implicated in neurological conditions such as Alzheimer's disease. Although AHN has been extensively observed in animal models for twenty years, its existence and persistence in humans have been widely debated in academia, heavily based on post-mortem immunohistochemical markers. Using the search engines PubMed and Google Scholar for “Adult Human Neurogenesis,” 143 articles that were most relevant to the history of AHN discovery, detection in rodents, immunohistochemical studies on post-mortem human sections, and therapeutic development targeting AHN were reviewed. This review article highlights the current understanding of AHN in rodents and humans, its implications in neurodegenerative diseases and therapeutics, and the inconsistencies and methodological variabilities encountered in studying AHN in humans. Furthermore, the correlation between AHN and diseases such as mood disorders and Alzheimer's disease is still not well established, with conflicting findings reported. Standardization of transcriptomic methodologies and increased availability of post-mortem human brain samples are crucial in advancing AHN research. This review article attempts to discover the fascinating and controversial world of adult human neurogenesis and its potential implications in treating neurological disorders. Apart from the discussion on AHN existence, tackling devastating diseases with this supplemental knowledge can lead to therapeutic advancements which greatly rely on understanding not only the presence of AHN but the mechanisms mediating its availability.

Lysophosphatidic acid signaling via LPA6: a negative modulator of developmental oligodendrocyte maturation

Journal of neurochemistry

2022 Sep 25

Spencer, SA;Suárez-Pozos, E;Verdugo, JS;Wang, H;Afshari, FS;Guo, L;Manam, S;Yasuda, D;Ortega, A;Lister, JA;Ishii, S;Zhang, Y;Fuss, B;
PMID: 36153691 | DOI: 10.1111/jnc.15696

The developmental process of central nervous system (CNS) myelin sheath formation is characterized by well-coordinated cellular activities ultimately ensuring rapid and synchronized neural communication. During this process, myelinating CNS cells, namely oligodendrocytes (OLGs), undergo distinct steps of differentiation, whereby the progression of earlier maturation stages of OLGs represents a critical step toward the timely establishment of myelinated axonal circuits. Given the complexity of functional integration, it is not surprising that OLG maturation is controlled by a yet fully to be defined set of both negative and positive modulators. In this context, we provide here first evidence for a role of lysophosphatidic acid (LPA) signaling via the G protein-coupled receptor LPA6 as a negative modulatory regulator of myelination-associated gene expression in OLGs. More specifically, cell surface accessibility of LPA6 was found to be restricted to the earlier maturation stages of differentiating OLGs, and OLG maturation was found to occur precociously in Lpar6 knockout mice. To further substantiate these findings, a novel small molecule ligand with selectivity for preferentially LPA6 and LPA6 agonist characteristics was functionally characterized in vitro in primary cultures of rat OLGs and in vivo in the developing zebrafish. Utilizing this approach, a negative modulatory role of LPA6 signaling in OLG maturation could be corroborated. During development, such a functional role of LPA6 signaling likely serves to ensure timely coordination of circuit formation and myelination. Under pathological conditions as seen in the major human demyelinating disease multiple sclerosis (MS), however, persistent LPA6 expression and signaling in OLGs can be seen as an inhibitor of myelin repair. Thus, it is of interest that LPA6 protein levels appear elevated in MS brain samples, thereby suggesting that LPA6 signaling may represent a potential new druggable pathway suitable to promote myelin repair in MS.This article is protected by

Distinct neural networks derived from galanin-containing nociceptors and neurotensin-expressing pruriceptors

Proceedings of the National Academy of Sciences of the United States of America

2022 Aug 16

Chen, Y;Song, Y;Wang, H;Zhang, Y;Hu, X;Wang, K;Lu, Y;Zhang, Z;Li, S;Li, A;Bao, L;Xu, F;Li, C;Zhang, X;
PMID: 35943985 | DOI: 10.1073/pnas.2118501119

Pain and itch are distinct sensations arousing evasion and compulsive desire for scratching, respectively. It's unclear whether they could invoke different neural networks in the brain. Here, we use the type 1 herpes simplex virus H129 strain to trace the neural networks derived from two types of dorsal root ganglia (DRG) neurons: one kind of polymodal nociceptors containing galanin (Gal) and one type of pruriceptors expressing neurotensin (Nts). The DRG microinjection and immunosuppression were performed in transgenic mice to achieve a successful tracing from specific types of DRG neurons to the primary sensory cortex. About one-third of nuclei in the brain were labeled. More than half of them were differentially labeled in two networks. For the ascending pathways, the spinothalamic tract was absent in the network derived from Nts-expressing pruriceptors, and the two networks shared the spinobulbar projections but occupied different subnuclei. As to the motor systems, more neurons in the primary motor cortex and red nucleus of the somatic motor system participated in the Gal-containing nociceptor-derived network, while more neurons in the nucleus of the solitary tract (NST) and the dorsal motor nucleus of vagus nerve (DMX) of the emotional motor system was found in the Nts-expressing pruriceptor-derived network. Functional validation of differentially labeled nuclei by c-Fos test and chemogenetic inhibition suggested the red nucleus in facilitating the response to noxious heat and the NST/DMX in regulating the histamine-induced scratching. Thus, we reveal the organization of neural networks in a DRG neuron type-dependent manner for processing pain and itch.

Single-cell RNA sequencing in oral science: Current awareness and perspectives

Cell proliferation

2022 Jul 17

Wu, J;Ding, Y;Wang, J;Lyu, F;Tang, Q;Song, J;Luo, Z;Wan, Q;Lan, X;Xu, Z;Chen, L;
PMID: 35842899 | DOI: 10.1111/cpr.13287

The emergence of single-cell RNA sequencing enables simultaneous sequencing of thousands of cells, making the analysis of cell population heterogeneity more efficient. In recent years, single-cell RNA sequencing has been used in the investigation of heterogeneous cell populations, cellular developmental trajectories, stochastic gene transcriptional kinetics, and gene regulatory networks, providing strong support in life science research. However, the application of single-cell RNA sequencing in the field of oral science has not been reviewed comprehensively yet. Therefore, this paper reviews the development and application of single-cell RNA sequencing in oral science, including fields of tissue development, teeth and jaws diseases, maxillofacial tumors, infections, etc., providing reference and prospects for using single-cell RNA sequencing in studying the oral diseases, tissue development, and regeneration.

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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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