MicroRNA-33 Deficiency in Macrophages Enhances Autophagy, Improves Mitochondrial Homeostasis, and Protects Against Lung Fibrosis
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE215948 | GEO | 2023/06/14
REPOSITORIES: GEO
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Project description:miR-33 is an intronic microRNA within the gene encoding the SREBP2 transcription factor. Like its host gene, miR-33 has been shown to be an important regulator of lipid metabolism. Inhibition of miR-33 has been shown to promote cholesterol efflux in macrophages by targeting the cholesterol transporter ABCA1, thus reducing atherosclerotic plaque burden. Inhibition of miR-33 has also been shown to improve high-density lipoprotein (HDL) biogenesis in the liver and increase circulating HDL-C levels in both rodents and nonhuman primates. However, evaluating the extent to which these changes in HDL metabolism contribute to atherogenesis has been hindered by the obesity and metabolic dysfunction observed in whole-body miR-33–knockout mice. To determine the impact of hepatic miR-33 deficiency on obesity, metabolic function, and atherosclerosis, we have generated a conditional knockout mouse model that lacks miR-33 only in the liver. Characterization of this model demonstrates that loss of miR-33 in the liver does not lead to increased body weight or adiposity. Hepatic miR-33 deficiency actually improves regulation of glucose homeostasis and impedes the development of fibrosis and inflammation. We further demonstrate that hepatic miR-33 deficiency increases circulating HDL-C levels and reverse cholesterol transport capacity in mice fed a chow diet, but these changes are not sufficient to reduce atherosclerotic plaque size under hyperlipidemic conditions. By elucidating the role of miR-33 in the liver and the impact of hepatic miR-33 deficiency on obesity and atherosclerosis, this work will help inform ongoing efforts to develop novel targeted therapies against cardiometabolic diseases.
2021-02-11 | PXD023471 | Pride
Project description:miR-33 is an intronic miRNA within the gene encoding the SREBP2 transcription factor. Like its host gene, miR-33 has been shown to be an important regulator of lipid metabolism. Inhibition of miR-33 has been shown to promote cholesterol efflux in macrophages by targeting the cholesterol transporter ABCA1, thus reducing atherosclerotic plaque burden. Inhibition of miR-33 has also been shown to improve HDL biogenesis in the liver and increase circulating HDL-C levels in both rodents and non-human primates. However, evaluating the extent to which these changes in HDL metabolism contribute to atherogenesis has been hindered by the obesity and metabolic dysfunction observed in whole body miR-33 knockout mice. To determine the impact of hepatic miR-33 deficiency on obesity, metabolic function and atherosclerosis, we have generated a conditional knockout mouse model that lacks miR-33 only in the liver. Characterization of this model demonstrates that loss of miR-33 in the liver does not lead to increased body weight or adiposity. Hepatic miR-33 deficiency actually improves regulation of glucose homeostasis and impedes the development of fibrosis and inflammation. We further demonstrate that hepatic miR-33 deficiency increases circulating HDL-C levels and reverse cholesterol transport capacity in mice fed a chow diet, but these changes are not sufficient to reduce atherosclerotic plaque size under hyperlipidemic conditions. By elucidating the role of miR-33 in the liver, and the impact of hepatic miR-33 deficiency on obesity and atherosclerosis, this work will help inform ongoing efforts to develop novel targeted therapies against cardio-metabolic diseases.
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Project description:Dysregulation of autophagy plays a pivotal role in fibrosis in multiple organs. However, the role of autophagy in peritendinous fibrosis is not well understood. Here, we hypothesize that autophagy plays a protective role in preventing adhesion formation. In a rat model of tendon injury, we observed dysregulated autophagy during excessive extracellular matrix deposition. Pharmacological induction of autophagy by rapamycin markedly alleviated the severity of peritendinous fibrosis in vivo. In NIH/3T3 fibroblasts and tenocytes, transforming growth factor ?1 (TGF-?1) markedly activated myofibroblasts and increased collagen synthesis. Addition of rapamycin activated autophagy, reduced collagen synthesis, and suppressed myofibroblast activation. In vitro experiments also showed that rapamycin decreased cell proliferation and increased the number of cells arrested in G0/G1 phase. However, following pretreatment with the autophagy inhibitor 3-methyladenine (3-MA), rapamycin was unable to repress the fibrotic changes induced by TGF-?1. Autophagy related protein 5 (Atg5) RNA interference in fibroblasts also abolished the protective effects of rapamycin in vitro. In conclusion, our results point to rapamycin as a potential treatment strategy in the prevention of peritendinous fibrosis after tendon injury.
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2016-08-09 | E-GEOD-73705 | biostudies-arrayexpress
Project description:Peritoneal metastasis (PM) has a suppressive tumor immune microenvironment (TIME), which limits the effects of immunotherapy. This study aims to investigate the immunomodulatory effects of intraperitoneal administration of IL-33 on PM-associated TIME. Immunocompetent mice were used to investigate the role of IL-33 in development of abdominal dissemination and host outcome. Murine (m) and human (h) gastric cancer cells were tested for their response to IL-33 by qRT-PCR, flow cytometry, and immunofluorescence. Survival was significantly prolonged in patients with high Il-33 mRNA expression. Intraperitoneal administration of IL-33 could induce the celiac inflammatory environment, activate immunologic effector cells and reverse the immunosuppressive tumor microenvironment, which delayed tumor progression and peritoneal metastasis of gastric cancer. Mechanistically, IL-33 could induce M2 polarization by activating p38-GATA-binding protein 3 (GATA3) signaling pathway. IL-33 combined with anti-CSF1R or p38 inhibitor to regulate tumor-associated macrophages (TAMs) showed synergistic anti-tumor effect. Intraperitoneal administration of IL-33 inducing local inflammatory milieu provided a novel approach for the treatment of metastatic peritoneal malignancies, which combined with TAMs reprogramming to reshape TIME could achieve better treatment efficacy.
2023-06-30 | GSE235526 | GEO
Project description:Non-alcoholic fatty liver disease (NAFLD) is the most frequent liver disease worldwide and can progress to non-alcoholic steatohepatitis (NASH), which is characterized by triglyceride accumulation, inflammation, and fibrosis. No pharmacological agents are currently approved to treat these conditions, but it is clear now that modulation of lipid synthesis and autophagy are key biological mechanisms that could help reduce or prevent these liver diseases. The folliculin (FLCN) protein has been recently identified as a central regulatory node governing whole body energy homeostasis, and we hypothesized that FLCN regulates highly metabolic tissues like the liver. We thus generated a liver specific Flcn knockout mouse model to study its role in liver disease progression. Using the methionine- and choline-deficient diet to mimic liver fibrosis, we demonstrate that loss of Flcn reduced triglyceride accumulation, fibrosis, and inflammation in mice. In this aggressive liver disease setting, loss of Flcn led to activation of transcription factors TFEB and TFE3 to promote autophagy, promoting the degradation of intracellular lipid stores, ultimately resulting in reduced hepatocellular damage and inflammation. Hence, the activity of FLCN could be a promising target for small molecule drugs to treat liver fibrosis by specifically activating autophagy. Collectively, these results show an unexpected role for Flcn in fatty liver disease progression and highlight new potential treatment strategies.
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Project description:Interleukin-33 in experimental kidney fibrosis
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Project description:Rationale: miRNA therapeutics have gained attention during the past decade. These oligonucleotide treatments can modulate the expression of miRNAs in vivo and could be used to correct the imbalance of gene expression found in human diseases such as obesity, metabolic syndrome and atherosclerosis. The in vivo efficacy of current anti-miRNAs technologies hindered by physiological and cellular barriers to delivery into targeted cells and the nature of miRNAs that allows one to target an entire pathway that may lead to deleterious off-target effects. For these reasons, novel targeted delivery systems to inhibit miRNAs in specific tissues will be important for developing effective therapeutic strategies for numerous diseases including atherosclerosis. Objective: To explore the application of anti-miR-33 (miR-33-5p) conjugated pH Low-Insertion Peptides (pHLIP) constructs for the specific targeting of macrophages located in vascular lesions in the regression of atherosclerosis. Methods and Results: The anti-miR-33 conjugated pHLIP constructs are preferentially delivered to atherosclerotic plaques macrophages. The inhibition of miR-33 using pHLIP-directed macrophage targeting improves atherosclerosis regression by increasing collagen content and decreased lipid accumulation within vascular lesions. Single cell RNA sequencing analysis revealed higher expression of fibrotic genes (Col2a1, Col3a1, Col1a2, Fn1, etc) and tissue inhibitor of metalloproteinase 3 (Timp3), and downregulation of matrix metallopeptidase 12 (Mmp12) in macrophages from atherosclerotic lesions targeted by pHLIP- anti-miR-33. Conclusions: This study provides proof of principle for the application of pHLIP for treating advanced atherosclerosis via pharmacological inhibition of miR-33 in macrophages that avoids the deleterious effects in other metabolic tissues. This may open new therapeutic opportunities for atherosclerosis-associated cardiovascular diseases via selective delivery of other protective miRNAs.
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Project description:Pneumonia-induced lung injury and acute respiratory distress syndrome can develop because of an inappropriate inflammatory response to acute infections, leading to a compromised alveolar barrier. Recent work suggests that hospitalized patients with allergies/asthma are less likely to die of pulmonary infections and that there is a correlation between survival from acute respiratory distress syndrome and higher eosinophil counts; thus, we hypothesized that eosinophils associated with a type 2 immune response may protect against pneumonia-induced acute lung injury. To test this hypothesis, mice were treated with the type 2-initiating cytokine IL-33 intratracheally 3 days before induction of pneumonia with airway administration of a lethal dose of Staphylococcus aureus. Interestingly, IL-33 pretreatment promoted survival by inhibiting acute lung injury: amount of BAL fluid proinflammatory cytokines and pulmonary edema were both reduced, with an associated increase in oxygen saturation. Pulmonary neutrophilia was also reduced, whereas eosinophilia was strongly increased. This eosinophilia was key to protection; eosinophil reduction eliminated both IL-33-mediated protection against mortality and inhibition of neutrophilia and pulmonary edema. Together, these data reveal a novel role for eosinophils in protection against lung injury and suggest that modulation of pulmonary type 2 immunity may represent a novel therapeutic strategy.
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