Science translational medicine
Liu, J;Trefry, JC;Babka, AM;Schellhase, CW;Coffin, KM;Williams, JA;Raymond, JLW;Facemire, PR;Chance, TB;Davis, NM;Scruggs, JL;Rossi, FD;Haddow, AD;Zelko, JM;Bixler, SL;Crozier, I;Iversen, PL;Pitt, ML;Kuhn, JH;Palacios, G;Zeng, X;
PMID: 35138912 | DOI: 10.1126/scitranslmed.abi5229
Effective therapeutics have been developed against acute Ebola virus disease (EVD) in both humans and experimentally infected nonhuman primates. However, the risk of viral persistence and associated disease recrudescence in survivors receiving these therapeutics remains unclear. In contrast to rhesus macaques that survived Ebola virus (EBOV) exposure in the absence of treatment, we discovered that EBOV, despite being cleared from all other organs, persisted in the brain ventricular system of rhesus macaque survivors that had received monoclonal antibody (mAb) treatment. In mAb-treated macaque survivors, EBOV persisted in macrophages infiltrating the brain ventricular system, including the choroid plexuses. This macrophage infiltration was accompanied by severe tissue damage, including ventriculitis, choroid plexitis, and meningoencephalitis. Specifically, choroid plexus endothelium-derived EBOV infection led to viral persistence in the macaque brain ventricular system. This resulted in apoptosis of ependymal cells, which constitute the blood-cerebrospinal fluid barrier of the choroid plexuses. Fatal brain-confined recrudescence of EBOV infection manifested as severe inflammation, local pathology, and widespread infection of the ventricular system and adjacent neuropil in some of the mAb-treated macaque survivors. This study highlights organ-specific EBOV persistence and fatal recrudescent disease in rhesus macaque survivors after therapeutic treatment and has implications for the long-term follow-up of human survivors of EVD.
Progress in retinal and eye research
Lewandowski, D;Sander, CL;Tworak, A;Gao, F;Xu, Q;Skowronska-Krawczyk, D;
PMID: 34971765 | DOI: 10.1016/j.preteyeres.2021.101037
The retinal pigment epithelium-photoreceptor interphase is renewed each day in a stunning display of cellular interdependence. While photoreceptors use photosensitive pigments to convert light into electrical signals, the RPE supports photoreceptors in their function by phagocytizing shed photoreceptor tips, regulating the blood retina barrier, and modulating inflammatory responses, as well as regenerating the 11-cis-retinal chromophore via the classical visual cycle. These processes involve multiple protein complexes, tightly regulated ligand-receptors interactions, and a plethora of lipids and protein-lipids interactions. The role of lipids in maintaining a healthy interplay between the RPE and photoreceptors has not been fully delineated. In recent years, novel technologies have resulted in major advancements in understanding several facets of this interplay, including the involvement of lipids in phagocytosis and phagolysosome function, nutrient recycling, and the metabolic dependence between the two cell types. In this review, we aim to integrate the complex role of lipids in photoreceptor and RPE function, emphasizing the dynamic exchange between the cells as well as discuss how these processes are affected in aging and retinal diseases.
Seeker, LA;Williams, A;
PMID: 34860266 | DOI: 10.1007/s00401-021-02390-4
It is the centenary of the discovery of oligodendrocytes and we are increasingly aware of their importance in the functioning of the brain in development, adult learning, normal ageing and in disease across the life course, even in those diseases classically thought of as neuronal. This has sparked more interest in oligodendroglia for potential therapeutics for many neurodegenerative/neurodevelopmental diseases due to their more tractable nature as a renewable cell in the central nervous system. However, oligodendroglia are not all the same. Even from the first description, differences in morphology were described between the cells. With advancing techniques to describe these differences in human tissue, the complexity of oligodendroglia is being discovered, indicating apparent functional differences which may be of critical importance in determining vulnerability and response to disease, and targeting of potential therapeutics. It is timely to review the progress we have made in discovering and understanding oligodendroglial heterogeneity in health and neuropathology.
The role of endoplasmic reticulum stress in astrocytes
Sims, SG;Cisney, RN;Lipscomb, MM;Meares, GP;
PMID: 34462963 | DOI: 10.1002/glia.24082
Astrocytes are glial cells that support neurological function in the central nervous system (CNS), in part, by providing structural support for neuronal synapses and blood vessels, participating in electrical and chemical transmission, and providing trophic support via soluble factors. Dysregulation of astrocyte function contributes to neurological decline in CNS diseases. Neurological diseases are highly heterogeneous but share common features of cellular stress including the accumulation of misfolded proteins. Endoplasmic reticulum (ER) stress has been reported in nearly all neurological and neurodegenerative diseases. ER stress occurs when there is an accumulation of misfolded proteins in the ER lumen and the protein folding demand of the ER is overwhelmed. ER stress initiates the unfolded protein response (UPR) to restore homeostasis by abating protein translation and, if the cell is irreparably damaged, initiating apoptosis. Although protein aggregation and misfolding in neurological disease has been well described, cell-specific contributions of ER stress and the UPR in physiological and disease states are poorly understood. Recent work has revealed a role for active UPR signaling that may drive astrocytes toward a maladaptive phenotype in various model systems. In response to ER stress, astrocytes produce inflammatory mediators, have reduced trophic support, and can transmit ER stress to other cells. This review will discuss the current known contributions and consequences of activated UPR signaling in astrocytes.
Myomixer is expressed during embryonic and post-larval hyperplasia, muscle regeneration and differentiation of myoblats in rainbow trout (Oncorhynchus mykiss)
Perello-Amoros, M;Rallière, C;Gutiérrez, J;Gabillard, JC;
PMID: 33961974 | DOI: 10.1016/j.gene.2021.145688
In contrast to mice or zebrafish, trout exhibits post-larval muscle growth through hypertrophy and formation of new myofibers (hyperplasia). The muscle fibers are formed by the fusion of mononucleated cells (myoblasts) regulated by several muscle-specific proteins such as Myomaker or Myomixer. In this work, we identified a unique gene encoding a Myomixer protein of 77 amino acids (aa) in the trout genome. Sequence analysis and phylogenetic tree showed moderate conservation of the overall protein sequence across teleost fish (61% of aa identity between trout and zebrafish Myomixer sequences). Nevertheless, the functionally essential motif, AxLyCxL is perfectly conserved in all studied sequences of vertebrates. Using in situ hybridization, we observed that myomixer was highly expressed in the embryonic myotome, particularly in the hyperplasic area. Moreover, myomixer remained readily expressed in white muscle of juvenile (1 and 20 g) although its expression decreased in mature fish. We also showed that myomixer is up-regulated during muscle regeneration and in vitro myoblasts differentiation. Together, these data indicate that myomixer expression is consistently associated with the formation of new myofibers during somitogenesis, post-larval growth and muscle regeneration in trout.
GPR151 in nociceptors modulates neuropathic pain via regulating P2X3 function and microglial activation
Brain : a journal of neurology
Xia, LP;Luo, H;Ma, Q;Xie, YK;Li, W;Hu, H;Xu, ZZ;
PMID: 34244727 | DOI: 10.1093/brain/awab245
Neuropathic pain is a major health problem that affects up to 7-10% of the population worldwide. Currently, neuropathic pain is difficult to treat due to its elusive mechanisms. Here we report that orphan G protein-coupled receptor 151 (GPR151) in nociceptive sensory neurons controls neuropathic pain induced by nerve injury. GPR151 was mainly expressed in nonpeptidergic C-fiber dorsal root ganglion (DRG) neurons and highly upregulated after nerve injury. Importantly, conditional knockout of Gpr151 in adult nociceptive sensory neurons significantly alleviated chronic constriction injury (CCI)-induced neuropathic pain-like behavior but did not affect basal nociception. Moreover, GPR151 in DRG neurons was required for CCI-induced neuronal hyperexcitability and upregulation of colony-stimulating factor 1 (CSF1), which is necessary for microglial activation in the spinal cord after nerve injury. Mechanistically, GPR151 coupled with P2X3 ion channels and promoted their functional activities in neuropathic pain-like hypersensitivity. Knockout of Gpr151 suppressed P2X3-mediated calcium elevation and spontaneous pain behavior in CCI mice. Conversely, overexpression of Gpr151 significantly enhanced P2X3-mediated calcium elevation and DRG neuronal excitability. Furthermore, knockdown of P2X3 in DRGs reversed CCI-induced CSF1 upregulation, spinal microglial activation, and neuropathic pain-like behavior. Finally, the co-expression of GPR151 and P2X3 was confirmed in small-diameter human DRG neurons, indicating the clinical relevance of our findings. Together, our results suggest that GPR151 in nociceptive DRG neurons plays a key role in the pathogenesis of neuropathic pain and could be a potential target for treating neuropathic pain.
Targeting netrin-3 in small cell lung cancer and neuroblastoma
Jiang, S;Richaud, M;Vieugué, P;Rama, N;Delcros, JG;Siouda, M;Sanada, M;Redavid, AR;Ducarouge, B;Hervieu, M;Breusa, S;Manceau, A;Gattolliat, CH;Gadot, N;Combaret, V;Neves, D;Ortiz-Cuaran, S;Saintigny, P;Meurette, O;Walter, T;Janoueix-Lerosey, I;Hofman, P;Mulligan, P;Goldshneider, D;Mehlen, P;Gibert, B;
PMID: 33719214 | DOI: 10.15252/emmm.202012878
The navigation cue netrin-1 is well-documented for its key role in cancer development and represents a promising therapeutic target currently under clinical investigation. Phase 1 and 2 clinical trials are ongoing with NP137, a humanized monoclonal antibody against netrin-1. Interestingly, the epitope recognized by NP137 in netrin-1 shares 90% homology with its counterpart in netrin-3, the closest member to netrin-1 in humans, for which little is known in the field of cancer. Here, we unveiled that netrin-3 appears to be expressed specifically in human neuroblastoma (NB) and small cell lung cancer (SCLC), two subtypes of neuroectodermal/neuroendocrine lineages. Netrin-3 and netrin-1 expression are mutually exclusive, and the former is driven by the MYCN oncogene in NB, and the ASCL-1 or NeuroD1 transcription factors in SCLC. Netrin-3 expression is correlated with disease stage, aggressiveness, and overall survival in NB. Mechanistically, we confirmed the high affinity of netrin-3 for netrin-1 receptors and we demonstrated that netrin-3 genetic silencing or interference using NP137, delayed tumor engraftment, and reduced tumor growth in animal models. Altogether, these data support the targeting of netrin-3 in NB and SCLC.
Ablation of kynurenine 3-monooxygenase rescues plasma inflammatory cytokine levels in the R6/2 mouse model of Huntington\'s disease
Bondulich, MK;Fan, Y;Song, Y;Giorgini, F;Bates, GP;
PMID: 33750843 | DOI: 10.1038/s41598-021-84858-7
Kynurenine 3-monooxygenase (KMO) regulates the levels of neuroactive metabolites in the kynurenine pathway (KP), dysregulation of which is associated with Huntington's disease (HD) pathogenesis. KMO inhibition leads to increased levels of neuroprotective relative to neurotoxic metabolites, and has been found to ameliorate disease-relevant phenotypes in several HD models. Here, we crossed KMO knockout mice to R6/2 HD mice to examine the effect of KMO depletion in the brain and periphery. KP genes were dysregulated in peripheral tissues from R6/2 mice and KMO ablation normalised levels of a subset of these. KP metabolites were also assessed, and KMO depletion led to increased levels of neuroprotective kynurenic acid in brain and periphery, and dramatically reduced neurotoxic 3-hydroxykunurenine levels in striatum and cortex. Notably, the increased levels of pro-inflammatory cytokines TNFa, IL1β, IL4 and IL6 found in R6/2 plasma were normalised upon KMO deletion. Despite these improvements in KP dysregulation and peripheral inflammation, KMO ablation had no effect upon several behavioural phenotypes. Therefore, although genetic inhibition of KMO in R6/2 mice modulates several metabolic and inflammatory parameters, these do not translate to improvements in primary disease indicators-observations which will likely be relevant for other interventions targeted at peripheral inflammation in HD.
Biochimica et biophysica acta. Reviews on cancer
Ahmed, R;Augustine, R;Valera, E;Ganguli, A;Mesaeli, N;Ahmad, IS;Bashir, R;Hasan, A;
PMID: 34861353 | DOI: 10.1016/j.bbcan.2021.188663
Spatial mapping of heterogeneity in gene expression in cancer tissues can improve our understanding of cancers and help in the rapid detection of cancers with high accuracy and reliability. Significant advancements have been made in recent years in OMICS technologies, which possess the strong potential to be applied in the spatial mapping of biopsy tissue samples and their molecular profiling to a single-cell level. The clinical application of OMICS technologies in spatial profiling of cancer tissues is also advancing. The current review presents recent advancements and prospects of applying OMICS technologies to the spatial mapping of various analytes in cancer tissues. We benchmark the current state of the art in the field to advance existing OMICS technologies for high throughput spatial profiling. The factors taken into consideration include spatial resolution, types of biomolecules, numbers of different biomolecules detected from the same assay, labeled versus label-free approaches, and approximate time required for each assay. Further advancements are still needed for the widespread application of OMICs technologies in performing fast and high throughput spatial mapping of cancer tissues as well as their effective use in research and clinical applications.
Sex-specific pubertal and metabolic regulation of Kiss1 neurons via Nhlh2
Leon, S;Talbi, R;McCarthy, EA;Ferrari, K;Fergani, C;Naule, L;Choi, JH;Carroll, RS;Kaiser, UB;Aylwin, CF;Lomniczi, A;Navarro, VM;
PMID: 34494548 | DOI: 10.7554/eLife.69765
Hypothalamic Kiss1 neurons control gonadotropin-releasing hormone release through the secretion of kisspeptin. Kiss1 neurons serve as a nodal center that conveys essential regulatory cues for the attainment and maintenance of reproductive function. Despite this critical role, the mechanisms that control kisspeptin synthesis and release remain largely unknown. Using Drop-Seq data from the arcuate nucleus of adult mice and in situ hybridization, we identified Nescient Helix-Loop-Helix 2 (Nhlh2), a transcription factor of the basic helix-loop-helix family, to be enriched in Kiss1 neurons. JASPAR analysis revealed several binding sites for NHLH2 in the Kiss1 and Tac2 (neurokinin B) 5' regulatory regions. In vitro luciferase assays evidenced a robust stimulatory action of NHLH2 on human KISS1 and TAC3 promoters. The recruitment of NHLH2 to the KISS1 and TAC3 promoters was further confirmed through chromatin immunoprecipitation. In vivo conditional ablation of Nhlh2 from Kiss1 neurons using Kiss1Cre:Nhlh2fl/fl mice induced a male-specific delay in puberty onset, in line with a decrease in arcuate Kiss1 expression. Females retained normal reproductive function albeit with irregular estrous cycles. Further analysis of male Kiss1Cre:Nhlh2fl/fl mice revealed higher susceptibility to metabolic challenges in the release of luteinizing hormone and impaired response to leptin. Overall, in Kiss1 neurons, Nhlh2 contributes to the metabolic regulation of kisspeptin and NKB synthesis and release, with implications for the timing of puberty onset and regulation of fertility in male mice.
Knockdown of circROBO2 attenuates acute myocardial infarction through regulating the miR-1184/TRADD axis
Molecular medicine (Cambridge, Mass.)
Chen, TP;Zhang, NJ;Wang, HJ;Hu, SG;Geng, X;
PMID: 33658002 | DOI: 10.1186/s10020-021-00275-6
Studies have found that circular RNAs (circRNAs) play key roles in cardiovascular diseases. However, the function of circROBO2 in acute myocardial infarction (AMI) is unclear. This study aimed to investigate the pathogenesis of circROBO2 in AMI. qRT-PCR and Western blot were used to determine the expression levels of circROBO2, miR-1184, and TRADD in AMI and sham-operated mouse models at mRNA and protein level, respectively. The relationship among miR-1184, circROBO2 and TRADD was evaluated by RNA immunoprecipitation (RIP) analysis and luciferase reporter gene analysis. The roles of circROBO2, miR-1184, and TRADD in myocardial cell apoptosis were evaluated using flow cytometry. Ultrasound echocardiography, serum creatine kinase MB (CK-MB) and lactate dehydrogenase (LDH), myocardial infarction area, and myocardial cell apoptosis were measured to examine the effects of circROBO2 on myocardial injury. The expression levels of miR-1184 were significantly reduced, and the expression levels of circROBO2 and TRADD were significantly increased in MI group. CircROBO2 acted as a sponge for miR-1184 by upregulating the expression of TRADD. In addition, overexpression of miR-1184 enhanced the protective effect of knockdown of circROBO2 by partially inhibiting the expression of TRADD in vivo and in vitro. Knockdown of circROBO2 reduced the apoptosis of cardiomyocytes by increasing the expression levels of miR-1184, which in turn decreased the expression levels of TRADD in the myocardium post-MI.
EZH2 is required for parathyroid and thymic development through differentiation of the third pharyngeal pouch endoderm
Disease models & mechanisms
Caprio, C;Lania, G;Bilio, M;Ferrentino, R;Chen, L;Baldini, A;
PMID: 33608392 | DOI: 10.1242/dmm.046789
The Ezh2 gene encodes a histone methyltransferase of the Polycomb Repressive Complex 2 that methylates histone H3 lysine 27. In this work we asked whether EZH2 has a role in the development of the pharyngeal apparatus and whether it regulates the expression of the Tbx1 gene, which encodes a key transcription factor required in pharyngeal development. To these ends, we performed genetic in vivo experiments with mouse embryos and we used mouse embryonic stem cell (ESC)-based protocols to probe endoderm and cardiogenic mesoderm differentiation. Results showed that EZH2 occupies the Tbx1 gene locus in mouse embryos, and that suppression of EZH2 was associated with reduced expression of Tbx1 in differentiated mESCs. Conditional deletion of Ezh2 in the Tbx1 expression domain, which includes the pharyngeal endoderm, did not cause cardiac defects but revealed that the gene has an important role in the morphogenesis of the 3rd pharyngeal pouch (PP). We found that in conditionally deleted embryos the 3rd PP was hypoplastic, had reduced expression of Tbx1, lacked the expression of Gcm2, a gene that marks the parathyroid domain, but expressed FoxN1, a gene marking the thymic domain. Consistently, the parathyroids did not develop, and the thymus was hypoplastic. Thus, Ezh2 is required for parathyroid and thymic development, probably through a function in the pouch endoderm. This discovery also provides a novel interpretational key for the finding of Ezh2 activating mutations in hyperparathyroidism and parathyroid cancer.