Nat Commun. 2018 Oct 30;9(1):4435.
Nomura S, Satoh M, Fujita T, Higo T, Sumida T, Ko T, Yamaguchi T, Tobita T, Naito AT, Ito M, Fujita K, Harada M, Toko H, Kobayashi Y, Ito K, Takimoto E, Akazawa H, Morita H, Aburatani H, Komuro I.
PMID: 30375404 | DOI: 10.1038/s41467-018-06639-7
Pressure overload induces a transition from cardiac hypertrophy to heart failure, but its underlying mechanisms remain elusive. Here we reconstruct a trajectory of cardiomyocyte remodeling and clarify distinct cardiomyocyte gene programs encoding morphological and functional signatures in cardiac hypertrophy and failure, by integrating single-cardiomyocyte transcriptome with cell morphology, epigenomic state and heart function. During early hypertrophy, cardiomyocytes activate mitochondrial translation/metabolism genes, whose expression is correlated with cell size and linked to ERK1/2 and NRF1/2 transcriptional networks. Persistent overload leads to a bifurcation into adaptive and failing cardiomyocytes, and p53 signaling is specifically activated in late hypertrophy. Cardiomyocyte-specific p53 deletion shows that cardiomyocyte remodeling is initiated by p53-independent mitochondrial activation and morphological hypertrophy, followed by p53-dependent mitochondrial inhibition, morphological elongation, and heart failure gene program activation. Human single-cardiomyocyte analysis validates the conservation of the pathogenic transcriptional signatures. Collectively, cardiomyocyte identity is encoded in transcriptional programs that orchestrate morphological and functional phenotypes.
Ramachandran, M;Vaccaro, A;van de Walle, T;Georganaki, M;Lugano, R;Vemuri, K;Kourougkiaouri, D;Vazaios, K;Hedlund, M;Tsaridou, G;Uhrbom, L;Pietilä, I;Martikainen, M;van Hooren, L;Olsson Bontell, T;Jakola, AS;Yu, D;Westermark, B;Essand, M;Dimberg, A;
PMID: 37172581 | DOI: 10.1016/j.ccell.2023.04.010
Glioblastomas are aggressive brain tumors that are largely immunotherapy resistant. This is associated with immunosuppression and a dysfunctional tumor vasculature, which hinder T cell infiltration. LIGHT/TNFSF14 can induce high endothelial venules (HEVs) and tertiary lymphoid structures (TLS), suggesting that its therapeutic expression could promote T cell recruitment. Here, we use a brain endothelial cell-targeted adeno-associated viral (AAV) vector to express LIGHT in the glioma vasculature (AAV-LIGHT). We found that systemic AAV-LIGHT treatment induces tumor-associated HEVs and T cell-rich TLS, prolonging survival in αPD-1-resistant murine glioma. AAV-LIGHT treatment reduces T cell exhaustion and promotes TCF1+CD8+ stem-like T cells, which reside in TLS and intratumoral antigen-presenting niches. Tumor regression upon AAV-LIGHT therapy correlates with tumor-specific cytotoxic/memory T cell responses. Our work reveals that altering vascular phenotype through vessel-targeted expression of LIGHT promotes efficient anti-tumor T cell responses and prolongs survival in glioma. These findings have broader implications for treatment of other immunotherapy-resistant cancers.
Timón-Gómez, A;Scharr, AL;Wong, NY;Ni, E;Roy, A;Liu, M;Chau, J;Lampert, JL;Hireed, H;Kim, NS;Jan, M;Gupta, AR;Day, RW;Gardner, JM;Wilson, RJA;Barrientos, A;Chang, AJ;
PMID: 36255054 | DOI: 10.7554/eLife.78915
Mammalian carotid body arterial chemoreceptors function as an early warning system for hypoxia, triggering acute life-saving arousal and cardiorespiratory reflexes. To serve this role, carotid body glomus cells are highly sensitive to decreases in oxygen availability. While the mitochondria and plasma membrane signaling proteins have been implicated in oxygen sensing by glomus cells, the mechanism underlying their mitochondrial sensitivity to hypoxia compared to other cells is unknown. Here, we identify HIGD1C, a novel hypoxia-inducible gene domain factor isoform, as an electron transport chain complex IV-interacting protein that is almost exclusively expressed in the carotid body and is therefore not generally necessary for mitochondrial function. Importantly, HIGD1C is required for carotid body oxygen sensing and enhances complex IV sensitivity to hypoxia. Thus, we propose that HIGD1C promotes exquisite oxygen sensing by the carotid body, illustrating how specialized mitochondria can be used as sentinels of metabolic stress to elicit essential adaptive behaviors.
Phillips, RA;Tuscher, JJ;Black, SL;Andraka, E;Fitzgerald, ND;Ianov, L;Day, JJ;
PMID: 35385745 | DOI: 10.1016/j.celrep.2022.110616
The ventral tegmental area (VTA) is a complex brain region that is essential for reward function and frequently implicated in neuropsychiatric disease. While decades of research on VTA function have focused on dopamine neurons, recent evidence has identified critical roles for GABAergic and glutamatergic neurons in reward processes. Additionally, although subsets of VTA neurons express genes involved in the synthesis and transport of multiple neurotransmitters, characterization of these combinatorial populations has largely relied on low-throughput methods. To comprehensively define the molecular architecture of the VTA, we performed single-nucleus RNA sequencing on 21,600 cells from the rat VTA. Analysis of neuronal subclusters identifies selective markers for dopamine and combinatorial neurons, reveals expression profiles for receptors targeted by drugs of abuse, and demonstrates population-specific enrichment of gene sets linked to brain disorders. These results highlight the heterogeneity of the VTA and provide a resource for further exploration of VTA gene expression.
Su, Q;Kim, S;Adewale, F;Zhou, Y;Aldler, C;Ni, M;Wei, Y;Burczynski, M;Atwal, G;Sleeman, M;Murphy, A;Xin, Y;Cheng, X;
| DOI: 10.1016/j.isci.2021.103233
Nonalcoholic fatty liver disease (NAFLD) is a global health-care problem with limited therapeutic options. To obtain a cellular resolution of pathogenesis, 82,168 single-cell transcriptomes (scRNA-seq) across different NAFLD stages were profiled, identifying hepatocytes and 12 other non-parenchymal cell (NPC) types. scRNA-seq revealed insights into the cellular and molecular mechanisms of the disease. We discovered a dual role for hepatic stellate cells in gene expression regulation and in the potential to trans-differentiate into myofibroblasts. We uncovered distinct expression profiles of Kupffer cells versus monocyte-derived macrophages during NAFLD progression. Kupffer cells showed stronger immune responses, while monocyte-derived macrophages demonstrated a capability for differentiation. Three chimeric NPCs were identified including endothelial-chimeric stellate cells, hepatocyte-chimeric endothelial cells, and endothelial-chimeric Kupffer cells. Our work identified unanticipated aspects of mouse with NAFLD at the single-cell level and advanced the understanding of cellular heterogeneity in NAFLD livers.
Xiao L, Priest MF, Kozorovitskiy Y.
PMID: 29676731 | DOI: 10.7554/eLife.33892
The experience of rewarding or aversive stimuli is encoded by distinct afferents to dopamine (DA) neurons of the ventral tegmental area (VTA). Several neuromodulatory systems including oxytocin regulate DA neuron excitability and synaptic transmission that process socially meaningful stimuli. We and others have recently characterized oxytocinergic modulation of activity in mouse VTA DA neurons, but the mechanisms underlying oxytocinergic modulation of synaptic transmission in DA neurons remain poorly understood. Here, we find that oxytocin application or optogenetic release decrease excitatory synaptic transmission, via long lasting, presynaptic, endocannabinoid-dependent mechanisms. Oxytocin modulation of excitatory transmission alters the magnitude of short and long-term depression. We find that only some glutamatergic projections to DA neurons express CB1 receptors. Optogenetic stimulation of three major VTA inputs demonstrates that oxytocin modulation is limited to projections that show evidence of CB1R transcripts. Thus, oxytocin gates information flow into reward circuits in a temporally selective and pathway-specific manner.
Girbl T, Lenn T, Perez L, Rolas L, Barkaway A, Thiriot A, del Fresno C, Lynam E, Hub E, Thelen M, Graham G, Alon R, Sancho D, von Andrian UH, Voisin MB, Rot A, Nourshargh S.
PMID: 30446388 | DOI: 10.1016/j.immuni.2018.09.018
Neutrophils require directional cues to navigate through the complex structure of venular walls and into inflamed tissues. Here we applied confocal intravital microscopy to analyze neutrophil emigration in cytokine-stimulated mouse cremaster muscles. We identified differential and non-redundant roles for the chemokines CXCL1 and CXCL2, governed by their distinct cellular sources. CXCL1 was produced mainly by TNF-stimulated endothelial cells (ECs) and pericytes and supported luminal and sub-EC neutrophil crawling. Conversely, neutrophils were the main producers of CXCL2, and this chemokine was critical for correct breaching of endothelial junctions. This pro-migratory activity of CXCL2 depended on the atypical chemokine receptor 1 (ACKR1), which is enriched within endothelial junctions. Transmigrating neutrophils promoted a self-guided migration response through EC junctions, creating a junctional chemokine "depot" in the form of ACKR1-presented CXCL2 that enabled efficient unidirectional luminal-to-abluminal migration. Thus, CXCL1 and CXCL2 act in a sequential manner to guide neutrophils through venular walls as governed by their distinct cellular sources.
Jais A, Paeger L, Sotelo-Hitschfeld T, Bremser S, Prinzensteiner M, Klemm P, Mykytiuk V, Widdershooven PJM, Vesting AJ, Grzelka K, Min�re M, Cremer AL, Xu J, Korotkova T, Lowell BB, Zeilhofer HU, Backes H, Fenselau H, Wunderlich FT, Kloppenburg P, Br�ning JC
PMID: 32302532 | DOI: 10.1016/j.neuron.2020.03.022
Calorie-rich diets induce hyperphagia and promote obesity, although the underlying mechanisms remain poorly defined. We find that short-term high-fat-diet (HFD) feeding of mice activates prepronociceptin (PNOC)-expressing neurons in the arcuate nucleus of the hypothalamus (ARC). PNOCARC neurons represent a previously unrecognized GABAergic population of ARC neurons distinct from well-defined feeding regulatory AgRP or POMC neurons. PNOCARC neurons arborize densely in the ARC and provide inhibitory synaptic input to nearby anorexigenic POMC neurons. Optogenetic activation of PNOCARC neurons in the ARC and their projections to the bed nucleus of the stria terminalis promotes feeding. Selective ablation of these cells promotes the activation of POMC neurons upon HFD exposure, reduces feeding, and protects from obesity, but it does not affect food intake or body weight under normal chow consumption. We characterize PNOCARC neurons as a novel ARC neuron population activated upon palatable food consumption to promote hyperphagia
He, Y;Madeo, G;Liang, Y;Zhang, C;Hempel, B;Liu, X;Mu, L;Liu, S;Bi, GH;Galaj, E;Zhang, HY;Shen, H;McDevitt, RA;Gardner, EL;Liu, QS;Xi, ZX;
PMID: 36054363 | DOI: 10.1126/sciadv.abo1440
Physical exercise is rewarding and protective against drug abuse and addiction. However, the neural mechanisms underlying these actions remain unclear. Here, we report that long-term wheel-running produced a more robust increase in c-fos expression in the red nucleus (RN) than in other brain regions. Anatomic and functional assays demonstrated that most RN magnocellular portion (RNm) neurons are glutamatergic. Wheel-running activates a subset of RNm glutamate neurons that project to ventral tegmental area (VTA) dopamine neurons. Optogenetic stimulation of this pathway was rewarding, as assessed by intracranial self-stimulation and conditioned place preference, whereas optical inhibition blocked wheel-running behavior. Running wheel access decreased cocaine self-administration and cocaine seeking during extinction. Last, optogenetic stimulation of the RNm-to-VTA glutamate pathway inhibited responding to cocaine. Together, these findings indicate that physical exercise activates a specific RNm-to-VTA glutamatergic pathway, producing exercise reward and reducing cocaine intake.
Agnew-Svoboda, W;Ubina, T;Figueroa, Z;Wong, YC;Vizcarra, EA;Roebini, B;Wilson, EH;Fiacco, TA;Riccomagno, MM;
PMID: 36046623 | DOI: 10.1016/j.crmeth.2022.100276
Astrocytes are vital support cells that ensure proper brain function. In brain disease, astrocytes reprogram into a reactive state that alters many of their cellular roles. A long-standing question in the field is whether downregulation of reactive astrocyte (RA) markers during resolution of inflammation is because these astrocytes revert back to a non-reactive state or die and are replaced. This has proven difficult to answer mainly because existing genetic tools cannot distinguish between healthy versus RAs. Here we describe the generation of an inducible genetic tool that can be used to specifically target and label a subset of RAs. Longitudinal analysis of an acute inflammation model using this tool revealed that the previously observed downregulation of RA markers after inflammation is likely due to changes in gene expression and not because of cell death. Our findings suggest that cellular changes associated with astrogliosis after acute inflammation are largely reversible.
Ayloo, S;Lazo, CG;Sun, S;Zhang, W;Cui, B;Gu, C;
PMID: 35294899 | DOI: 10.1016/j.neuron.2022.02.017
Endothelial cells of blood vessels of the central nervous system (CNS) constitute blood-CNS barriers. Barrier properties are not intrinsic to these cells; rather they are induced and maintained by CNS microenvironment. Notably, the abluminal surfaces of CNS capillaries are ensheathed by pericytes and astrocytes. However, extrinsic factors from these perivascular cells that regulate barrier integrity are largely unknown. Here, we establish vitronectin, an extracellular matrix protein secreted by CNS pericytes, as a regulator of blood-CNS barrier function via interactions with its integrin receptor, α5, in endothelial cells. Genetic ablation of vitronectin or mutating vitronectin to prevent integrin binding, as well as endothelial-specific deletion of integrin α5, causes barrier leakage in mice. Furthermore, vitronectin-integrin α5 signaling maintains barrier integrity by actively inhibiting transcytosis in endothelial cells. These results demonstrate that signaling from perivascular cells to endothelial cells via ligand-receptor interactions is a key mechanism to regulate barrier permeability.
Coordination of endothelial cell positioning and fate specification by the epicardium
Quijada, P;Trembley, MA;Misra, A;Myers, JA;Baker, CD;Pérez-Hernández, M;Myers, JR;Dirkx, RA;Cohen, ED;Delmar, M;Ashton, JM;Small, EM;
PMID: 34230480 | DOI: 10.1038/s41467-021-24414-z
The organization of an integrated coronary vasculature requires the specification of immature endothelial cells (ECs) into arterial and venous fates based on their localization within the heart. It remains unclear how spatial information controls EC identity and behavior. Here we use single-cell RNA sequencing at key developmental timepoints to interrogate cellular contributions to coronary vessel patterning and maturation. We perform transcriptional profiling to define a heterogenous population of epicardium-derived cells (EPDCs) that express unique chemokine signatures. We identify a population of Slit2+ EPDCs that emerge following epithelial-to-mesenchymal transition (EMT), which we term vascular guidepost cells. We show that the expression of guidepost-derived chemokines such as Slit2 are induced in epicardial cells undergoing EMT, while mesothelium-derived chemokines are silenced. We demonstrate that epicardium-specific deletion of myocardin-related transcription factors in mouse embryos disrupts the expression of key guidance cues and alters EPDC-EC signaling, leading to the persistence of an immature angiogenic EC identity and inappropriate accumulation of ECs on the epicardial surface. Our study suggests that EC pathfinding and fate specification is controlled by a common mechanism and guided by paracrine signaling from EPDCs linking epicardial EMT to EC localization and fate specification in the developing heart.
