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Cell Research Oct 2021Glioblastoma (GBM) is a prevalent and highly lethal form of glioma, with rapid tumor progression and frequent recurrence. Excessive outgrowth of pericytes in GBM governs...
Glioblastoma (GBM) is a prevalent and highly lethal form of glioma, with rapid tumor progression and frequent recurrence. Excessive outgrowth of pericytes in GBM governs the ecology of the perivascular niche, but their function in mediating chemoresistance has not been fully explored. Herein, we uncovered that pericytes potentiate DNA damage repair (DDR) in GBM cells residing in the perivascular niche, which induces temozolomide (TMZ) chemoresistance. We found that increased pericyte proportion correlates with accelerated tumor recurrence and worse prognosis. Genetic depletion of pericytes in GBM xenografts enhances TMZ-induced cytotoxicity and prolongs survival of tumor-bearing mice. Mechanistically, C-C motif chemokine ligand 5 (CCL5) secreted by pericytes activates C-C motif chemokine receptor 5 (CCR5) on GBM cells to enable DNA-dependent protein kinase catalytic subunit (DNA-PKcs)-mediated DDR upon TMZ treatment. Disrupting CCL5-CCR5 paracrine signaling through the brain-penetrable CCR5 antagonist maraviroc (MVC) potently inhibits pericyte-promoted DDR and effectively improves the chemotherapeutic efficacy of TMZ. GBM patient-derived xenografts with high CCL5 expression benefit from combined treatment with TMZ and MVC. Our study reveals the role of pericytes as an extrinsic stimulator potentiating DDR signaling in GBM cells and suggests that targeting CCL5-CCR5 signaling could be an effective therapeutic strategy to improve chemotherapeutic efficacy against GBM.
Topics: Animals; Cell Line, Tumor; Drug Resistance, Neoplasm; Glioblastoma; Mice; Paracrine Communication; Pericytes; Temozolomide; Xenograft Model Antitumor Assays
PubMed: 34239070
DOI: 10.1038/s41422-021-00528-3 -
Molecular Cell May 2021Cellular senescence is a state of stable proliferative arrest triggered by damaging signals. Senescent cells persist during aging and promote age-related pathologies via...
Cellular senescence is a state of stable proliferative arrest triggered by damaging signals. Senescent cells persist during aging and promote age-related pathologies via the pro-inflammatory senescence-associated secretory phenotype (SASP), whose regulation depends on environmental factors. In vivo, a major environmental variable is oxygenation, which varies among and within tissues. Here, we demonstrate that senescent cells express lower levels of detrimental pro-inflammatory SASP factors in physiologically hypoxic environments, as measured in culture and in tissues. Mechanistically, exposure of senescent cells to low-oxygen conditions leads to AMPK activation and AMPK-mediated suppression of the mTOR-NF-κB signaling loop. Finally, we demonstrate that treatment with hypoxia-mimetic compounds reduces SASP in cells and tissues and improves strength in chemotherapy-treated and aged mice. Our findings highlight the importance of oxygen as a determinant for pro-inflammatory SASP expression and offer a potential new strategy to reduce detrimental paracrine effects of senescent cells.
Topics: AMP-Activated Protein Kinases; Age Factors; Animals; Antibiotics, Antineoplastic; Cell Hypoxia; Cell Line, Tumor; Cell Proliferation; Cellular Senescence; Doxorubicin; Glycine; Humans; Hydroxybenzoates; Hypoxia; Inflammation Mediators; Isoquinolines; Mice, Inbred C57BL; Muscle Strength; NF-kappa B; Paracrine Communication; Phenotype; Signal Transduction; TOR Serine-Threonine Kinases; Mice
PubMed: 33823141
DOI: 10.1016/j.molcel.2021.03.018 -
The EMBO Journal Dec 2019Cellular senescence has been shown to contribute to skin ageing. However, the role of melanocytes in the process is understudied. Our data show that melanocytes are the...
Cellular senescence has been shown to contribute to skin ageing. However, the role of melanocytes in the process is understudied. Our data show that melanocytes are the only epidermal cell type to express the senescence marker p16 during human skin ageing. Aged melanocytes also display additional markers of senescence such as reduced HMGB1 and dysfunctional telomeres, without detectable telomere shortening. Additionally, senescent melanocyte SASP induces telomere dysfunction in paracrine manner and limits proliferation of surrounding cells via activation of CXCR3-dependent mitochondrial ROS. Finally, senescent melanocytes impair basal keratinocyte proliferation and contribute to epidermal atrophy in vitro using 3D human epidermal equivalents. Crucially, clearance of senescent melanocytes using the senolytic drug ABT737 or treatment with mitochondria-targeted antioxidant MitoQ suppressed this effect. In conclusion, our study provides proof-of-concept evidence that senescent melanocytes affect keratinocyte function and act as drivers of human skin ageing.
Topics: Adult; Aged; Aged, 80 and over; Aging; Atrophy; Cells, Cultured; Cellular Senescence; Cyclin-Dependent Kinase Inhibitor p16; Epidermis; Female; Humans; Male; Melanocytes; Middle Aged; Paracrine Communication; Reactive Oxygen Species; Receptors, CXCR4; Skin; Telomere; Young Adult
PubMed: 31633821
DOI: 10.15252/embj.2019101982 -
Circulation Jun 2021Arrhythmogenic cardiomyopathy (ACM) manifests with sudden death, arrhythmias, heart failure, apoptosis, and myocardial fibro-adipogenesis. The phenotype typically starts...
BACKGROUND
Arrhythmogenic cardiomyopathy (ACM) manifests with sudden death, arrhythmias, heart failure, apoptosis, and myocardial fibro-adipogenesis. The phenotype typically starts at the epicardium and advances transmurally. Mutations in genes encoding desmosome proteins, including DSP (desmoplakin), are major causes of ACM.
METHODS
To delineate contributions of the epicardium to the pathogenesis of ACM, the allele was conditionally deleted in the epicardial cells in mice upon expression of tamoxifen-inducible Cre from the locus. Wild type (WT) and were crossed to Rosa26 (R26) dual reporter mice to tag the epicardial-derived cells with the EGFP (enhanced green fluorescent protein) reporter protein. Tagged epicardial-derived cells from adult :R26 and : R26 mouse hearts were isolated by fluorescence-activated cell staining and sequenced by single-cell RNA sequencing.
RESULTS
WT1 (Wilms tumor 1) expression was progressively restricted postnatally and was exclusive to the epicardium by postnatal day 21. Expression of was reduced in the epicardial cells but not in cardiac myocytes in the mice. The mice exhibited premature death, cardiac dysfunction, arrhythmias, myocardial fibro-adipogenesis, and apoptosis. Single-cell RNA sequencing of ≈18 000 EGFP-tagged epicardial-derived cells identified genotype-independent clusters of endothelial cells, fibroblasts, epithelial cells, and a very small cluster of cardiac myocytes, which were confirmed on coimmunofluorescence staining of the myocardial sections. Differentially expressed genes between the paired clusters in the 2 genotypes predicted activation of the inflammatory and mitotic pathways-including the TGFβ1 (transforming growth factor β1) and fibroblast growth factors-in the epicardial-derived fibroblast and epithelial clusters, but predicted their suppression in the endothelial cell cluster. The findings were corroborated by analysis of gene expression in the pooled RNA-sequencing data, which identified predominant dysregulation of genes involved in epithelial-mesenchymal transition, and dysregulation of 146 genes encoding the secreted proteins (secretome), including genes in the TGFβ1 pathway. Activation of the TGFβ1 and its colocalization with fibrosis in the :R26 mouse heart was validated by complementary methods.
CONCLUSIONS
Epicardial-derived cardiac fibroblasts and epithelial cells express paracrine factors, including TGFβ1 and fibroblast growth factors, which mediate epithelial-mesenchymal transition, and contribute to the pathogenesis of myocardial fibrosis, apoptosis, arrhythmias, and cardiac dysfunction in a mouse model of ACM. The findings uncover contributions of the epicardial-derived cells to the pathogenesis of ACM.
Topics: Animals; Cardiomyopathies; Disease Models, Animal; Humans; Mice; Paracrine Communication; Pericardium; Sequence Analysis, RNA; Single-Cell Analysis; Survival Analysis
PubMed: 33726497
DOI: 10.1161/CIRCULATIONAHA.120.052928 -
Science Signaling Oct 2022The tumor microbiome is increasingly implicated in cancer progression and resistance to chemotherapy. In pancreatic ductal adenocarcinoma (PDAC), high intratumoral loads...
The tumor microbiome is increasingly implicated in cancer progression and resistance to chemotherapy. In pancreatic ductal adenocarcinoma (PDAC), high intratumoral loads of correlate with shorter survival in patients. Here, we investigated the potential mechanisms underlying this association. We found that infection induced both normal pancreatic epithelial cells and PDAC cells to secrete increased amounts of the cytokines GM-CSF, CXCL1, IL-8, and MIP-3α. These cytokines increased proliferation, migration, and invasive cell motility in both infected and noninfected PDAC cells but not in noncancerous pancreatic epithelial cells, suggesting autocrine and paracrine signaling to PDAC cells. This phenomenon occurred in response to infection regardless of the strain and in the absence of immune and other stromal cells. Blocking GM-CSF signaling markedly limited proliferative gains after infection. Thus, infection in the pancreas elicits cytokine secretion from both normal and cancerous cells that promotes phenotypes in PDAC cells associated with tumor progression. The findings support the importance of exploring host-microbe interactions in pancreatic cancer to guide future therapeutic interventions.
Topics: Humans; Fusobacterium nucleatum; Granulocyte-Macrophage Colony-Stimulating Factor; Paracrine Communication; Interleukin-8; Pancreatic Neoplasms; Carcinoma, Pancreatic Ductal; Cell Proliferation; Pancreas
PubMed: 36256708
DOI: 10.1126/scisignal.abn4948 -
Circulation Research Jan 2021Previous translational studies implicate plasma extracellular microRNA-30d (miR-30d) as a biomarker in left ventricular remodeling and clinical outcome in heart failure...
RATIONALE
Previous translational studies implicate plasma extracellular microRNA-30d (miR-30d) as a biomarker in left ventricular remodeling and clinical outcome in heart failure (HF) patients, although precise mechanisms remain obscure.
OBJECTIVE
To investigate the mechanism of miR-30d-mediated cardioprotection in HF.
METHODS AND RESULTS
In rat and mouse models of ischemic HF, we show that miR-30d gain of function (genetic, lentivirus, or agomiR-mediated) improves cardiac function, decreases myocardial fibrosis, and attenuates cardiomyocyte (CM) apoptosis. Genetic or locked nucleic acid-based knock-down of miR-30d expression potentiates pathological left ventricular remodeling, with increased dysfunction, fibrosis, and cardiomyocyte death. RNA sequencing of in vitro miR-30d gain and loss of function, together with bioinformatic prediction and experimental validation in cardiac myocytes and fibroblasts, were used to identify and validate direct targets of miR-30d. miR-30d expression is selectively enriched in cardiomyocytes, induced by hypoxic stress and is acutely protective, targeting MAP4K4 (mitogen-associate protein kinase 4) to ameliorate apoptosis. Moreover, miR-30d is secreted primarily in extracellular vesicles by cardiomyocytes and inhibits fibroblast proliferation and activation by directly targeting integrin α5 in the acute phase via paracrine signaling to cardiac fibroblasts. In the chronic phase of ischemic remodeling, lower expression of miR-30d in the heart and plasma extracellular vesicles is associated with adverse remodeling in rodent models and human subjects and is linked to whole-blood expression of genes implicated in fibrosis and inflammation, consistent with observations in model systems.
CONCLUSIONS
These findings provide the mechanistic underpinning for the cardioprotective association of miR-30d in human HF. More broadly, our findings support an emerging paradigm involving intercellular communication of extracellular vesicle-contained miRNAs (microRNAs) to transregulate distinct signaling pathways across cell types. Functionally validated RNA biomarkers and their signaling networks may warrant further investigation as novel therapeutic targets in HF.
Topics: Animals; Apoptosis; Cells, Cultured; Disease Models, Animal; Extracellular Vesicles; Fibroblasts; Fibrosis; Gene Expression Regulation; Male; Mice, Inbred C57BL; Mice, Transgenic; MicroRNAs; Myocardial Infarction; Myocardium; Myocytes, Cardiac; Paracrine Communication; Protein Serine-Threonine Kinases; Rats, Sprague-Dawley; Rats, Transgenic; Signal Transduction; Ventricular Function, Left; Ventricular Remodeling; NF-kappaB-Inducing Kinase; Mice; Rats
PubMed: 33092465
DOI: 10.1161/CIRCRESAHA.120.317244 -
Cell Oct 2023The assembly of the neuronal and other major cell type programs occurred early in animal evolution. We can reconstruct this process by studying non-bilaterians like...
The assembly of the neuronal and other major cell type programs occurred early in animal evolution. We can reconstruct this process by studying non-bilaterians like placozoans. These small disc-shaped animals not only have nine morphologically described cell types and no neurons but also show coordinated behaviors triggered by peptide-secreting cells. We investigated possible neuronal affinities of these peptidergic cells using phylogenetics, chromatin profiling, and comparative single-cell genomics in four placozoans. We found conserved cell type expression programs across placozoans, including populations of transdifferentiating and cycling cells, suggestive of active cell type homeostasis. We also uncovered fourteen peptidergic cell types expressing neuronal-associated components like the pre-synaptic scaffold that derive from progenitor cells with neurogenesis signatures. In contrast, earlier-branching animals like sponges and ctenophores lacked this conserved expression. Our findings indicate that key neuronal developmental and effector gene modules evolved before the advent of cnidarian/bilaterian neurons in the context of paracrine cell signaling.
Topics: Animals; Biological Evolution; Ctenophora; Gene Expression; Neurons; Phylogeny; Single-Cell Analysis; Invertebrates; Paracrine Communication
PubMed: 37729907
DOI: 10.1016/j.cell.2023.08.027 -
Journal of Hepatology Aug 2020Following acetaminophen (APAP) overdose, acute liver injury (ALI) can occur in patients that present too late for N-acetylcysteine treatment, potentially leading to...
BACKGROUND & AIM
Following acetaminophen (APAP) overdose, acute liver injury (ALI) can occur in patients that present too late for N-acetylcysteine treatment, potentially leading to acute liver failure, systemic inflammation, and death. Macrophages influence the progression and resolution of ALI due to their innate immunological function and paracrine activity. Syngeneic primary bone marrow-derived macrophages (BMDMs) were tested as a cell-based therapy in a mouse model of APAP-induced ALI (APAP-ALI).
METHODS
Several phenotypically distinct BMDM populations were delivered intravenously to APAP-ALI mice when hepatic necrosis was established, and then evaluated based on their effects on injury, inflammation, immunity, and regeneration. In vivo phagocytosis assays were used to interrogate the phenotype and function of alternatively activated BMDMs (AAMs) post-injection. Finally, primary human AAMs sourced from healthy volunteers were evaluated in immunocompetent APAP-ALI mice.
RESULTS
BMDMs rapidly localised to the liver and spleen within 4 h of administration. Injection of AAMs specifically reduced hepatocellular necrosis, HMGB1 translocation, and infiltrating neutrophils following APAP-ALI. AAM delivery also stimulated proliferation in hepatocytes and endothelium, and reduced levels of several circulating proinflammatory cytokines within 24 h. AAMs displayed a high phagocytic activity both in vitro and in injured liver tissue post-injection. Crosstalk with the host innate immune system was demonstrated by reduced infiltrating host Ly6C macrophages in AAM-treated mice. Importantly, therapeutic efficacy was partially recapitulated using clinical-grade primary human AAMs in immunocompetent APAP-ALI mice, underscoring the translational potential of these findings.
CONCLUSION
We identify that AAMs have value as a cell-based therapy in an experimental model of APAP-ALI. Human AAMs warrant further evaluation as a potential cell-based therapy for APAP overdose patients with established liver injury.
LAY SUMMARY
After an overdose of acetaminophen (paracetamol), some patients present to hospital too late for the current antidote (N-acetylcysteine) to be effective. We tested whether macrophages, an injury-responsive leukocyte that can scavenge dead/dying cells, could serve as a cell-based therapy in an experimental model of acetaminophen overdose. Injection of alternatively activated macrophages rapidly reduced liver injury and reduced several mediators of inflammation. Macrophages show promise to serve as a potential cell-based therapy for acute liver injury.
Topics: Acetaminophen; Animals; Cell- and Tissue-Based Therapy; Chemical and Drug Induced Liver Injury; Cytokines; Disease Models, Animal; Humans; Immunity, Innate; Intercellular Signaling Peptides and Proteins; Liver Regeneration; Macrophages; Mice; Paracrine Communication; Phagocytosis; Treatment Outcome
PubMed: 32169610
DOI: 10.1016/j.jhep.2020.02.031 -
Nature Communications Jan 2021IL11 is important for fibrosis in non-alcoholic steatohepatitis (NASH) but its role beyond the stroma in liver disease is unclear. Here, we investigate the role of IL11...
IL11 is important for fibrosis in non-alcoholic steatohepatitis (NASH) but its role beyond the stroma in liver disease is unclear. Here, we investigate the role of IL11 in hepatocyte lipotoxicity. Hepatocytes highly express IL11RA and secrete IL11 in response to lipid loading. Autocrine IL11 activity causes hepatocyte death through NOX4-derived ROS, activation of ERK, JNK and caspase-3, impaired mitochondrial function and reduced fatty acid oxidation. Paracrine IL11 activity stimulates hepatic stellate cells and causes fibrosis. In mouse models of NASH, hepatocyte-specific deletion of Il11ra1 protects against liver steatosis, fibrosis and inflammation while reducing serum glucose, cholesterol and triglyceride levels and limiting obesity. In mice deleted for Il11ra1, restoration of IL11 cis-signaling in hepatocytes reconstitutes steatosis and inflammation but not fibrosis. We found no evidence for the existence of IL6 or IL11 trans-signaling in hepatocytes or NASH. These data show that IL11 modulates hepatocyte metabolism and suggests a mechanism for NAFLD to NASH transition.
Topics: Adult; Animals; Autocrine Communication; Cells, Cultured; Disease Models, Animal; Feeding Behavior; Hepatic Stellate Cells; Hepatocytes; Humans; Interleukin-11; Interleukin-11 Receptor alpha Subunit; Interleukin-6; Lipids; Mice, Knockout; Models, Biological; Non-alcoholic Fatty Liver Disease; Paracrine Communication; Phenotype; Signal Transduction; Mice
PubMed: 33397952
DOI: 10.1038/s41467-020-20303-z -
The Journal of Experimental Medicine Sep 2023Obesity and type 2 diabetes (T2D) are the leading causes of the progressive decline in muscle regeneration and fitness in adults. The muscle microenvironment is known to...
Obesity and type 2 diabetes (T2D) are the leading causes of the progressive decline in muscle regeneration and fitness in adults. The muscle microenvironment is known to play a key role in controlling muscle stem cell regenerative capacity, yet the underlying mechanism remains elusive. Here, we found that Baf60c expression in skeletal muscle is significantly downregulated in obese and T2D mice and humans. Myofiber-specific ablation of Baf60c in mice impairs muscle regeneration and contraction, accompanied by a robust upregulation of Dkk3, a muscle-enriched secreted protein. Dkk3 inhibits muscle stem cell differentiation and attenuates muscle regeneration in vivo. Conversely, Dkk3 blockade by myofiber-specific Baf60c transgene promotes muscle regeneration and contraction. Baf60c interacts with Six4 to synergistically suppress myocyte Dkk3 expression. While muscle expression and circulation levels of Dkk3 are markedly elevated in obese mice and humans, Dkk3 knockdown improves muscle regeneration in obese mice. This work defines Baf60c in myofiber as a critical regulator of muscle regeneration through Dkk3-mediated paracrine signaling.
Topics: Humans; Adult; Mice; Animals; Paracrine Communication; Diabetes Mellitus, Type 2; Mice, Obese; Muscle, Skeletal; Regeneration
PubMed: 37284884
DOI: 10.1084/jem.20221123