CXCR3-CXCL11 signaling restricts angiogenesis and promotes pericyte recruitment

Endothelial cell (EC)-pericyte interactions are known to remodel in response to hemodynamic forces, yet there is a lack of mechanistic understanding of the signaling pathways that underlie these events. Here, we have identified a novel signaling network regulated by blood flow in ECs-the chemokine receptor, CXCR3, and one of its ligands, CXCL11-that delimits EC angiogenic potential and suppresses pericyte recruitment during development through regulation of pdgfb expression in ECs. In vitro modeling of EC-pericyte interactions demonstrates that suppression of EC-specific CXCR3 signaling leads to loss of pericyte association with EC tubes. In vivo, phenotypic defects are particularly noted in the cranial vasculature, where we see a loss of pericyte association with and expansion of the vasculature in zebrafish treated with the Cxcr3 inhibitor AMG487. We also demonstrate using flow modeling platforms that CXCR3-deficient ECs are more elongated, move more slowly, and have impaired EC-EC junctions compared to their control counterparts. Together these data suggest that CXCR3 signaling in ECs drives vascular stabilization events during development.

Placental transcriptomic signatures of spontaneous preterm birth

BACKGROUND

Spontaneous preterm birth accounts for most preterm births and leads to significant morbidity in the newborn and childhood period. This subtype of preterm birth represents an increasing proportion of all preterm births when compared with medically indicated preterm birth, yet it is understudied in omics analyses. The placenta is a key regulator of fetal and newborn health, and the placental transcriptome can provide insight into pathologic changes that lead to spontaneous preterm birth.

OBJECTIVE

This analysis aimed to identify genes for which placental expression was associated with spontaneous preterm birth (including early preterm and late preterm birth).

STUDY DESIGN

The ECHO PATHWAYS consortium extracted RNA from placental samples collected from the Conditions Affecting Neurocognitive Development and Learning in Early Childhood and the Global Alliance to Prevent Prematurity and Stillbirth studies. Placental transcriptomic data were obtained by RNA sequencing. Linear models were fit to estimate differences in placental gene expression between term birth and spontaneous preterm birth (including gestational age subgroups defined by the American College of Obstetricians and Gynecologists). Models were adjusted for numerous confounding variables, including labor status, cohort, and RNA sequencing batch. This analysis excluded patients with induced labor, chorioamnionitis, multifetal gestations, or medical indications for preterm birth. Our combined cohort contained gene expression data for 14,023 genes in 48 preterm and 540 term samples. Genes and pathways were considered statistically significantly different at false discovery rate-adjusted P value of <.05.

RESULTS

In total, we identified 1728 genes for which placental expression was associated with spontaneous preterm birth with more differences in expression in early preterm samples than late preterm samples when compared with full-term samples. Of those, 9 genes were significantly decreased in both early and late spontaneous preterm birth, and the strongest associations involved placental expression of IL1B, ALPL, and CRLF1. In early and late preterm samples, we observed decreased expression of genes involved in immune signaling, signal transduction, and endocrine function.

CONCLUSION

This study provides a comprehensive assessment of the differences in the placental transcriptome associated with spontaneous preterm birth with robust adjustment for confounding. Results of this study are in alignment with the known etiology of spontaneous preterm birth, because we identified multiple genes and pathways for which the placental and chorioamniotic membrane expression was previously associated with prematurity, including IL1B. We identified decreased expression in key signaling pathways that are essential for placental growth and function, which may be related to the etiology of spontaneous preterm birth. We identified increased expression of genes within metabolic pathways associated exclusively with early preterm birth. These signaling and metabolic pathways may provide clinically targetable pathways and biomarkers. The findings presented here can be used to understand underlying pathologic changes in premature placentas, which can inform and improve clinical obstetrics practice.

The Chemokine Receptor CCR5 Links Memory CD4+ T Cell Metabolism to T Cell Antigen Receptor Nanoclustering

The inhibition of anabolic pathways, such as aerobic glycolysis, is a metabolic cornerstone of memory T cell differentiation and function. However, the signals that hamper these anabolic pathways are not completely known. Recent evidence pinpoints the chemokine receptor CCR5 as an important player in CD4⁺ T cell memory responses by regulating T cell antigen receptor (TCR) nanoclustering in an antigen-independent manner. This paper reports that CCR5 specifically restrains aerobic glycolysis in memory-like CD4⁺ T cells, but not in effector CD4⁺ T cells. CCR5-deficient memory CD4⁺ T cells thus show an abnormally high glycolytic/oxidative metabolism ratio. No CCR5-dependent change in glucose uptake nor in the expression of the main glucose transporters was detected in any of the examined cell types, although CCR5-deficient memory cells did show increased expression of the hexokinase 2 and pyruvate kinase M2 isoforms, plus the concomitant downregulation of Bcl-6, a transcriptional repressor of these key glycolytic enzymes. Further, the TCR nanoclustering defects observed in CCR5-deficient antigen-experienced CD4⁺ T cells were partially reversed by incubation with 2-deoxyglucose (2-DG), suggesting a link between inhibition of the glycolytic pathway and TCR nanoscopic organization. Indeed, the treatment of CCR5-deficient lymphoblasts with 2-DG enhanced IL-2 production after antigen re-stimulation. These results identify CCR5 as an important regulator of the metabolic fitness of memory CD4⁺ T cells, and reveal an unexpected link between T cell metabolism and TCR organization with potential influence on the response of memory T cells upon antigen re-encounter.

Genomic Fabric Remodeling in Metastatic Clear Cell Renal Cell Carcinoma (ccRCC): A New Paradigm and Proposal for a Personalized Gene Therapy Approach

Simple Summary

We applied the genomic fabric principles for personalized gene therapy to a case of clear cell renal cell carcinoma (ccRCC). Despite decades of research, the process of finding the molecular mechanisms responsible for the disease and, more importantly, the therapeutic solution is still a work in progress. We analyzed the transcriptomes of the chest wall metastasis, two distinct cancer nodules, and the cancer-free surrounding tissue in the surgically removed right kidney of a Fuhrman grade 3 metastatic ccRCC patient. The studies revealed that even histopathologically equally classified cancer nodules from the same kidney have different transcriptomic topologies, requiring tailored therapeutic solutions not only for each patient but even for each cancer nodule. We identified death-associated protein kinase 3 (DAPK3); transcription activation suppressor (TASOR); family with sequence similarity 27, member C, long non-coding RNA (FAM27C); and UDP-N-acetylglucosaminyltransferase subunit (ALG13) as the gene master regulators of the four profiled regions and proposed molecular mechanisms by which expression manipulation of TASOR and ALG13 may selectively destroy the cancer cells without affecting many of the normal cells.

Abstract

Published transcriptomic data from surgically removed metastatic clear cell renal cell carcinoma samples were analyzed from the genomic fabric paradigm (GFP) perspective to identify the best targets for gene therapy. GFP considers the transcriptome as a multi-dimensional mathematical object constrained by a dynamic set of expression controls and correlations among genes. Every gene in the chest wall metastasis, two distinct cancer nodules, and the surrounding normal tissue of the right kidney was characterized by three independent measures: average expression level, relative expression variation, and expression correlation with each other gene. The analyses determined the cancer-induced regulation, control, and remodeling of the chemokine and vascular endothelial growth factor (VEGF) signaling, apoptosis, basal transcription factors, cell cycle, oxidative phosphorylation, renal cell carcinoma, and RNA polymerase pathways. Interestingly, the three cancer regions exhibited different transcriptomic organization, suggesting that the gene therapy should not be personalized only for every patient but also for each major cancer nodule. The gene hierarchy was established on the basis of gene commanding height, and the gene master regulators DAPK3,TASOR, FAM27C and ALG13 were identified in each profiled region. We delineated the molecular mechanisms by which TASOR overexpression and ALG13 silencing would selectively affect the cancer cells with little consequences for the normal cells.

Immunogenetic Association Underlying Severe COVID-19

SARS-CoV2 has caused the current pandemic of new coronavirus disease 2019 (COVID-19) worldwide. Clinical outcomes of COVID-19 illness range broadly from asymptotic and mild to a life-threatening situation. This casts uncertainties for defining host determinants underlying the disease severity. Recent genetic analyses based on extensive clinical sample cohorts using genome-wide association studies (GWAS) and high throughput sequencing curation revealed genetic errors and gene loci associated with about 20% of life-threatening COVID-19 cases. Significantly, most of these critical genetic loci are enriched in two immune signaling pathways, i.e., interferon-mediated antiviral signaling and chemokine-mediated/inflammatory signaling. In line with these genetic profiling studies, the broad spectrum of COVID-19 illness could be explained by immuno-pathological regulation of these critical immunogenetic pathways through various epigenetic mechanisms, which further interconnect to other vital components such as those in the renin-angiotensin-aldosterone system (RAAS) because of its direct interaction with the virus causing COVID-19. Together, key genes unraveled by genetic profiling may provide targets for precisely early risk diagnosis and prophylactic design to relieve severe COVID-19. The confounding epigenetic mechanisms may be key to understanding the clinical broadness of COVID-19 illness.

Cadherin-Mediated Cell Coupling Coordinates Chemokine Sensing across Collectively Migrating Cells

The directed migration of cells sculpts the embryo, contributes to homeostasis in the adult, and, when dysregulated, underlies many diseases [1, 2]. During these processes, cells move singly or as a collective. In both cases, they follow guidance cues, which direct them to their destination [3-6]. In contrast to single cells, collectively migrating cells need to coordinate with their neighbors to move together in the same direction. Recent studies suggest that leader cells in the front sense the guidance cue, relay the directional information to the follower cells in the back, and can pull the follower cells along [7-19]. In this manner, leader cells steer the collective and set the collective's overall speed. However, whether follower cells also participate in steering and speed setting of the collective is largely unclear. Using chimeras, we analyzed the role of leader and follower cells in the collectively migrating zebrafish posterior lateral line primordium. This tissue expresses the chemokine receptor Cxcr4 and is guided by the chemokine Cxcl12a [20-23]. We find that leader and follower cells need to sense the attractant Cxcl12a for efficient migration, are coupled to each other through cadherins, and require coupling to pull Cxcl12a-insensitive cells along. Analysis of cell dynamics in chimeric and protein-depleted primordia shows that Cxcl12a-sensing and cadherin-mediated adhesion contribute jointly to direct migration at both single-cell and tissue levels. These results suggest that all cells in the primordium need to sense the attractant and adhere to each other to coordinate their movements and migrate with robust directionality.

Cellular Environment Remodels the Genomic Fabrics of Functional Pathways in Astrocytes

We profiled the transcriptomes of primary mouse cortical astrocytes cultured alone or co-cultured with immortalized precursor oligodendrocytes (Oli-neu cells). Filters between the cell types prevented formation of hetero-cellular gap junction channels but allowed for free exchange of the two culture media. We previously reported that major functional pathways in the Oli-neu cells are remodeled by the proximity of non-touching astrocytes and that astrocytes and oligodendrocytes form a panglial transcriptomic syncytium in the brain. Here, we present evidence that the astrocyte transcriptome likewise changes significantly in the proximity of non-touching Oli-neu cells. Our results indicate that the cellular environment strongly modulates the transcriptome of each cell type and that integration in a heterocellular tissue changes not only the expression profile but also the expression control and networking of the genes in each cell phenotype. The significant decrease of the overall transcription control suggests that in the co-culture astrocytes are closer to their normal conditions from the brain. The Oli-neu secretome regulates astrocyte genes known to modulate neuronal synaptic transmission and remodels calcium, chemokine, NOD-like receptor, PI3K-Akt, and thyroid hormone signaling, as well as actin-cytoskeleton, autophagy, cell cycle, and circadian rhythm pathways. Moreover, the co-culture significantly changes the gene hierarchy in the astrocytes.

Insights Into the Somatic Mutation Burden of Hepatoblastomas From Brazilian Patients

Hepatoblastoma is a very rare embryonal liver cancer supposed to arise from the impairment of hepatocyte differentiation during embryogenesis. In this study, we investigated by exome sequencing the burden of somatic mutations in a cohort of 10 hepatoblastomas, including a congenital case. Our data disclosed a low mutational background and pointed out to a novel set of candidate genes for hepatoblastoma biology, which were shown to impact gene expression levels. Only three recurrently mutated genes were detected: CTNNB1 and two novel candidates, CX3CL1 and CEP164. A relevant finding was the identification of a recurrent mutation (A235G) in two hepatoblastomas at the CX3CL1 gene; evaluation of RNA and protein expression revealed upregulation of CX3CL1 in tumors. The analysis was replicated in two independents cohorts, substantiating that an activation of the CX3CL1/CX3CR1 pathway occurs in hepatoblastomas. In inflammatory regions of hepatoblastomas, CX3CL1/CX3CR1 were not detected in the infiltrated lymphocytes, in which they should be expressed in normal conditions, whereas necrotic regions exhibited negative labeling in tumor cells, but strongly positive infiltrated lymphocytes. Altogether, these data suggested that CX3CL1/CX3CR1 upregulation may be a common feature of hepatoblastomas, potentially related to chemotherapy response and progression. In addition, three mutational signatures were identified in hepatoblastomas, two of them with predominance of either the COSMIC signatures 1 and 6, found in all cancer types, or the COSMIC signature 29, mostly related to tobacco chewing habit; a third novel mutational signature presented an unspecific pattern with an increase of C>A mutations. Overall, we present here novel candidate genes for hepatoblastoma, with evidence that CX3CL1/CX3CR1 chemokine signaling pathway is likely involved with progression, besides reporting specific mutational signatures.

The Human Cytomegalovirus US27 Gene Product Constitutively Activates Antioxidant Response Element-Mediated Transcription through Gβγ, Phosphoinositide 3-Kinase, and Nuclear Respiratory Factor 1

Human cytomegalovirus (HCMV) is a widespread pathogen that modulates host chemokine signaling during persistent infection in the host. HCMV encodes four proteins with homology to the chemokine receptor family of G protein-coupled receptors (GPCRs): US27, US28, UL33, and UL78. Each of the four receptors modulates host CXCR4 signaling. US28, UL33, and UL78 impair CXCR4 signaling outcomes, while US27 enhances signaling, as evidenced by increased calcium mobilization and cell migration to CXCL12. To investigate the effects of US27 on CXCR4 during virus infection, fibroblasts were infected with bacterial artificial chromosome-derived clinical strain HCMV TB40/E-mCherry (wild type [WT]), mutants lacking US27 (TB40/E-mCherry-US27Δ [US27Δ]) or all four GPCRs (TB40 E-mCherry-allΔ), or mutants expressing only US27 but not US28, UL33, or UL78 (TB40/E-mCherry-US27wt [US27wt]). CXCR4 gene expression was significantly higher in WT- and US27wt-infected fibroblasts. This effect was evident at 3 h postinfection, suggesting that US27 derived from the parental virion enhanced CXCR4 expression. Reporter gene assays demonstrated that US27 increased transcriptional activity regulated by the antioxidant response element (ARE), and small interfering RNA treatment indicated that this effect was mediated by NRF-1, the primary transcription factor for CXCR4. Increased translocation of NRF-1 into the nucleus of WT-infected cells compared to mock- or US27Δ-infected cells was confirmed by immunofluorescence microscopy. Chemical inhibitors targeting G_βγ and phosphoinositide 3-kinase (PI3K) ablated the increase in ARE-driven transcription, implicating these proteins as mediators of US27-stimulated gene transcription. This work identifies the first signaling pathway activated by HCMV US27 and may reveal a novel regulatory function for this orphan viral receptor in stimulating stress response genes during infection.IMPORTANCE Human cytomegalovirus (HCMV) is the most common congenital infection worldwide, causing deafness, blindness, and other serious birth defects. CXCR4 is a human chemokine receptor that is crucial for both fetal development and immune responses. We found that the HCMV protein US27 stimulates increased expression of CXCR4 through activation of the transcription factor nuclear respiratory factor 1 (NRF-1). NRF-1 regulates stress response genes that contain the antioxidant response element (ARE), and HCMV infection is associated with increased expression of many stress response genes when US27 is present. Our results show that the US27 protein activates the NRF-1/ARE pathway, stimulating higher expression of CXCR4 and other stress response genes, which is likely to be beneficial for virus replication and/or immune evasion.

Knockdown of FOXP1 promotes the development of lung adenocarcinoma

Lung cancer is one of the most common cancers in the world, which accounts for about 27% of all cancer deaths. However, the mechanisms underlying the pathogenesis of lung cancer cells remain largely elusive. In this study, we examined the role of the Forkhead box protein P1 (FOXP1) in lung cancer development. Our Oncomine analysis shows that FOXP1 is downregulated in lung adenocarcinoma compared with normal lung tissue. Knockdown of FOXP1 promotes the growth and invasion of PC9 and A549 cells by regulating genes of chemokine signaling molecules, including CCR1, ADCY5, GNG7, VAV3, and PLCB1. Simultaneous knockdown of CCR1 and FOXP1 attenuated FOXP1 knockdown-induced increase of lung cancer cell growth. Finally, knockdown of FOXP1 in PC9 cells promotes the tumorigenesis via CCR1 signaling in xenograft mouse model. Taken together, our data suggest that FOXP1 plays important roles in preventing lung adenocarcinoma development via suppressing chemokine signaling pathways.

Fam65b Phosphorylation Relieves Tonic RhoA Inhibition During T Cell Migration

We previously identified Fam65b as an atypical inhibitor of the small G protein RhoA. Using a conditional model of a Fam65b-deficient mouse, we first show that Fam65b restricts spontaneous RhoA activation in resting T lymphocytes and regulates intranodal T cell migration in vivo. We next aimed at understanding, at the molecular level, how the brake that Fam65b exerts on RhoA can be relieved upon signaling to allow RhoA activation. Here, we show that chemokine stimulation phosphorylates Fam65b in T lymphocytes. This post-translational modification decreases the affinity of Fam65b for RhoA and favors Fam65b shuttling from the plasma membrane to the cytosol. Functionally, we show that the degree of Fam65b phosphorylation controls some cytoskeletal alterations downstream active RhoA such as actin polymerization, as well as T cell migration in vitro. Altogether, our results show that Fam65b expression and phosphorylation can finely tune the amount of active RhoA in order to favor optimal T lymphocyte motility.

Pitx2c orchestrates embryonic axis extension via mesendodermal cell migration

Pitx2c, a homeodomain transcription factor, is classically known for its left-right patterning role. However, an early wave of pitx2 expression occurs at the onset of gastrulation in several species, indicating a possible earlier role that remains relatively unexplored. Here we show that in zebrafish, maternal-zygotic (MZ) pitx2c mutants exhibit a shortened body axis indicative of convergence and extension (CE) defects. Live imaging reveals that MZpitx2c mutants display less persistent mesendodermal migration during late stages of gastrulation. Transplant data indicate that Pitx2c functions cell non-autonomously to regulate this cell behavior by modulating cell shape and protrusive activity. Using transcriptomic analyses and candidate gene approaches, we identify transcriptional changes in components of the chemokine-ECM-integrin dependent mesendodermal migration network. Together, our results define pathways downstream of Pitx2c that are required during early embryogenesis and reveal novel functions for Pitx2c as a regulator of morphogenesis.

CX3CL1 is up-regulated in the rat hippocampus during memory-associated synaptic plasticity

Several cytokines and chemokines are now known to play normal physiological roles in the brain where they act as key regulators of communication between neurons, glia, and microglia. In particular, cytokines and chemokines can affect cardinal cellular and molecular processes of hippocampal-dependent long-term memory consolidation including synaptic plasticity, synaptic scaling and neurogenesis. The chemokine, CX₃CL1 (fractalkine), has been shown to modulate synaptic transmission and long-term potentiation (LTP) in the CA1 pyramidal cell layer of the hippocampus. Here, we confirm widespread expression of CX₃CL1 on mature neurons in the adult rat hippocampus. We report an up-regulation in CX₃CL1 protein expression in the CA1, CA3 and dentate gyrus (DG) of the rat hippocampus 2 h after spatial learning in the water maze task. Moreover, the same temporal increase in CX₃CL1 was evident following LTP-inducing theta-burst stimulation in the DG. At physiologically relevant concentrations, CX₃CL1 inhibited LTP maintenance in the DG. This attenuation in dentate LTP was lost in the presence of GABA_A receptor/chloride channel antagonism. CX₃CL1 also had opposing actions on glutamate-mediated rise in intracellular calcium in hippocampal organotypic slice cultures in the presence and absence of GABA_A receptor/chloride channel blockade. Using primary dissociated hippocampal cultures, we established that CX₃CL1 reduces glutamate-mediated intracellular calcium rises in both neurons and glia in a dose dependent manner. In conclusion, CX₃CL1 is up-regulated in the hippocampus during a brief temporal window following spatial learning the purpose of which may be to regulate glutamate-mediated neurotransmission tone. Our data supports a possible role for this chemokine in the protective plasticity process of synaptic scaling.

Inhibition of cellular and systemic inflammation cues in human bronchial epithelial cells by melanocortin-related peptides: mechanism of KPV action and a role for MC3R agonists

BACKGROUND/AIMS

Chemokine signaling from airway epithelium regulates macrophage recruitment to the lung in inflammatory diseases such as asthma. This study investigates the mechanism by which the α-melanocyte stimulating hormone-derived tripeptide, KPV, and the agonist of the dominant melanocortin receptor in airway epithelium (MC3R), γ-melanocyte stimulating hormone (γ-MSH), suppress inflammation in immortalised human bronchial airway epithelium.

METHODS

TNFα and rhino syncitial virus (RSV)-evoked nuclear factor-κB (NFκB) signaling was measured in immortalised human bronchial epithelial cells (16HBE14o-) in response to KPV and γMSH. Cellular and systemic inflammatory signaling was measured by NFκB reporter gene and chemokine (IL8, eotaxin) secretion, respectively.

RESULTS

KPV and γMSH evoked a dose-dependent inhibition of NFκB, matrix metalloproteinase-9 activity, IL8 and eotaxin secretion. The KPV effect was associated with its nuclear import, IκBα stabilisation and suppressed nuclear translocation of YFP-tagged p65RelA. Competition assays revealed an interaction between KPV and the Imp-α3 binding site on p65RelA which may involve blockade of the importin-α armadillo domain 7 and 8. In contrast, the γMSH anti-inflammatory effect required MC3R whose apical expression occurred in epithelium distributed along the length of the respiratory tree in vivo.

CONCLUSION

KPV and γMSH respectively suppress NFκB signalling in airway epithelium by: i) inhibition of p65RelA nuclear import and, ii) epithelial MC3R activation. Melanocortin peptides therefore provide a robust mechanism for targeting airway inflammation in lung disease.

Functional inactivation of CXC chemokine receptor 4-mediated responses through SOCS3 up-regulation

Hematopoietic cell growth, differentiation, and chemotactic responses require coordinated action between cytokines and chemokines. Cytokines promote receptor oligomerization, followed by Janus kinase (JAK) kinase activation, signal transducers and transactivators of transcription (STAT) nuclear translocation, and transcription of cytokine-responsive genes. These include genes that encode a family of negative regulators of cytokine signaling, the suppressors of cytokine signaling (SOCS) proteins. After binding their specific receptors, chemokines trigger receptor dimerization and activate the JAK/STAT pathway. We show that SOCS3 overexpression or up-regulation, stimulated by a cytokine such as growth hormone, impairs the response to CXCL12, measured by Ca(2+) flux and chemotaxis in vitro and in vivo. This effect is mediated by SOCS3 binding to the CXC chemokine receptor 4 receptor, blocking JAK/STAT and Galpha(i) pathways, without interfering with cell surface chemokine receptor expression. The data provide clear evidence for signaling cross-talk between cytokine and chemokine responses in building a functional immune system.