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Science (New York, N.Y.) Aug 2023The intestinal microbiota regulates mammalian lipid absorption, metabolism, and storage. We report that the microbiota reprograms intestinal lipid metabolism in mice by...
The intestinal microbiota regulates mammalian lipid absorption, metabolism, and storage. We report that the microbiota reprograms intestinal lipid metabolism in mice by repressing the expression of long noncoding RNA (lncRNA) (small nucleolar RNA host gene 9) in small intestinal epithelial cells. suppressed the activity of peroxisome proliferator-activated receptor γ (PPARγ)-a central regulator of lipid metabolism-by dissociating the PPARγ inhibitor sirtuin 1 from cell cycle and apoptosis protein 2 (CCAR2). Forced expression of in the intestinal epithelium of conventional mice impaired lipid absorption, reduced body fat, and protected against diet-induced obesity. The microbiota repressed expression through an immune relay encompassing myeloid cells and group 3 innate lymphoid cells. Our findings thus identify an unanticipated role for a lncRNA in microbial control of host metabolism.
Topics: Animals; Mice; Gastrointestinal Microbiome; Immunity, Innate; Lipid Metabolism; Lymphocytes; PPAR gamma; RNA, Long Noncoding; Sirtuin 1; Cell Cycle Proteins; Apoptosis Regulatory Proteins; Myeloid Cells; Intestines; Adipose Tissue; Humans
PubMed: 37616368
DOI: 10.1126/science.ade0522 -
Proceedings of the National Academy of... Jul 2023Plant intracellular nucleotide-binding domain, leucine-rich repeat-containing receptors (NLRs) activate a robust immune response upon detection of pathogen effectors....
Plant intracellular nucleotide-binding domain, leucine-rich repeat-containing receptors (NLRs) activate a robust immune response upon detection of pathogen effectors. How NLRs induce downstream immune defense genes remains poorly understood. The Mediator complex plays a central role in transducing signals from gene-specific transcription factors to the transcription machinery for gene transcription/activation. In this study, we demonstrate that MED10b and MED7 of the Mediator complex mediate jasmonate-dependent transcription repression, and coiled-coil NLRs (CNLs) in modulate MED10b/MED7 to activate immunity. Using the tomato CNL , which confers resistance to , as a model, we found that the CC domain of Sw-5b directly interacts with MED10b. Knockout/down of and other subunits including of the middle module of Mediator activates plant defense against . MED10b was found to directly interact with MED7, and MED7 directly interacts with JAZ proteins, which function as transcriptional repressors of jasmonic acid (JA) signaling. MED10b-MED7-JAZ together can strongly repress the expression of JA-responsive genes. The activated Sw-5b CC interferes with the interaction between MED10b and MED7, leading to the activation of JA-dependent defense signaling against . Furthermore, we found that CC domains of various other CNLs including helper NLR NRCs from modulate MED10b/MED7 to activate defense against different pathogens. Together, our findings reveal that MED10b/MED7 serve as a previously unknown repressor of jasmonate-dependent transcription repression and are modulated by diverse CNLs in to activate the JA-specific defense pathways.
Topics: Plant Immunity; Cyclopentanes; Transcription Factors; Mediator Complex; Arabidopsis Proteins
PubMed: 37399403
DOI: 10.1073/pnas.2302226120 -
The EMBO Journal Oct 2023Cold stress is a major abiotic stress that adversely affects plant growth and crop productivity. The C-REPEAT BINDING FACTOR/DRE BINDING FACTOR 1 (CBF/DREB1)...
Cold stress is a major abiotic stress that adversely affects plant growth and crop productivity. The C-REPEAT BINDING FACTOR/DRE BINDING FACTOR 1 (CBF/DREB1) transcriptional regulatory cascade plays a key role in regulating cold acclimation and freezing tolerance in Arabidopsis (Arabidopsis thaliana). Here, we show that max (more axillary growth) mutants deficient in strigolactone biosynthesis and signaling display hypersensitivity to freezing stress. Exogenous application of GR24 , a strigolactone analog, enhances freezing tolerance in wild-type plants and strigolactone-deficient mutants and promotes the cold-induced expression of CBF genes. Biochemical analysis showed that the transcription factor WRKY41 serves as a substrate for the F-box E3 ligase MAX2. WRKY41 directly binds to the W-box in the promoters of CBF genes and represses their expression, negatively regulating cold acclimation and freezing tolerance. MAX2 ubiquitinates WRKY41, thus marking it for cold-induced degradation and thereby alleviating the repression of CBF expression. In addition, SL-mediated degradation of SMXLs also contributes to enhanced plant freezing tolerance by promoting anthocyanin biosynthesis. Taken together, our study reveals the molecular mechanism underlying strigolactones promote the cold stress response in Arabidopsis.
PubMed: 37622245
DOI: 10.15252/embj.2022112999 -
Science Advances Oct 2023Neuroinflammation is a pathological change that is involved in the progression of Parkinson's disease. Dysfunction of chaperone-mediated autophagy (CMA) has...
Neuroinflammation is a pathological change that is involved in the progression of Parkinson's disease. Dysfunction of chaperone-mediated autophagy (CMA) has proinflammatory effects. However, the mechanism by which CMA mediates inflammation and whether CMA affects microglia and microglia-mediated neuronal damage remain to be elucidated. In the present study, we found that LAMP2A, a limiting protein for CMA, was decreased in lipopolysaccharide (LPS)-treated primary microglia. Activation of CMA by the activator CA significantly repressed LPS-induced microglial activation, whereas CMA dysfunction exacerbated microglial activation. We further identified that the protein p300 was a substrate of CMA. Degradation of p300 by CMA reduced p65 acetylation, thereby inhibiting the transcription of proinflammatory factors and the activation of the NLRP3 inflammasome. Furthermore, CA pretreatment inhibited microglia-mediated inflammation and, in turn, attenuated neuronal death in vitro and in vivo. Our findings suggest repressive effects of CMA on microglial activation through the p300-associated NF-κB signaling pathway, thus uncovering a mechanistic link between CMA and neuroinflammation.
Topics: Humans; NF-kappa B; Lipopolysaccharides; Microglia; NLR Family, Pyrin Domain-Containing 3 Protein; Chaperone-Mediated Autophagy; Neuroinflammatory Diseases; Inflammation
PubMed: 37801503
DOI: 10.1126/sciadv.adi8343 -
Nature Communications Aug 2023PPARα corepressor NCoR1 is a key regulator of fatty acid β-oxidation and ketogenesis. However, its regulatory mechanism is largely unknown. Here, we report that...
PPARα corepressor NCoR1 is a key regulator of fatty acid β-oxidation and ketogenesis. However, its regulatory mechanism is largely unknown. Here, we report that oncoprotein p21-activated kinase 4 (PAK4) is an NCoR1 kinase. Specifically, PAK4 phosphorylates NCoR1 at T1619/T2124, resulting in an increase in its nuclear localization and interaction with PPARα, thereby repressing the transcriptional activity of PPARα. We observe impaired ketogenesis and increases in PAK4 protein and NCoR1 phosphorylation levels in liver tissues of high fat diet-fed mice, NAFLD patients, and hepatocellular carcinoma patients. Forced overexpression of PAK4 in mice represses ketogenesis and thereby increases hepatic fat accumulation, whereas genetic ablation or pharmacological inhibition of PAK4 exhibites an opposite phenotype. Interestingly, PAK4 protein levels are significantly suppressed by fasting, largely through either cAMP/PKA- or Sirt1-mediated ubiquitination and proteasome degradation. In this way, our findings provide evidence for a PAK4-NCoR1/PPARα signaling pathway that regulates fatty acid β-oxidation and ketogenesis.
Topics: Animals; Mice; Co-Repressor Proteins; Fatty Acids; p21-Activated Kinases; PPAR alpha; Nuclear Receptor Co-Repressor 1; Humans; Phosphorylation; Signal Transduction
PubMed: 37591884
DOI: 10.1038/s41467-023-40597-z -
The EMBO Journal Oct 2023WRKY transcription factors in plants are known to be able to mediate either transcriptional activation or repression, but the mechanism regulating their transcriptional...
WRKY transcription factors in plants are known to be able to mediate either transcriptional activation or repression, but the mechanism regulating their transcriptional activity is largely unclear. We found that group IId WRKY transcription factors interact with OBERON (OBE) proteins, forming redundant WRKY-OBE complexes in Arabidopsis thaliana. The coiled-coil domain of WRKY transcription factors binds to OBE proteins and is responsible for target gene selection and transcriptional repression. The PHD finger of OBE proteins binds to both histones and WRKY transcription factors. WRKY-OBE complexes repress the transcription of numerous stress-responsive genes and are required for maintaining normal plant growth. Several WRKY and OBE mutants show reduced plant size and increased drought tolerance, accompanied by increased expression of stress-responsive genes. Moreover, expression levels of most of these WRKY and OBE genes are reduced in response to drought stress, revealing a previously uncharacterized regulatory mechanism of the drought stress response. These results suggest that WRKY-OBE complexes repress transcription of stress-responsive genes, and thereby balance plant growth and stress tolerance.
Topics: Transcription Factors; Histones; Plant Proteins; Arabidopsis; Stress, Physiological; Gene Expression Regulation, Plant; Plants, Genetically Modified; Phylogeny
PubMed: 37565504
DOI: 10.15252/embj.2023113639 -
Blood Cancer Discovery Sep 2023Cancer initiation is orchestrated by an interplay between tumor-initiating cells and their stromal/immune environment. Here, by adapted single-cell RNA sequencing, we...
UNLABELLED
Cancer initiation is orchestrated by an interplay between tumor-initiating cells and their stromal/immune environment. Here, by adapted single-cell RNA sequencing, we decipher the predicted signaling between tissue-resident hematopoietic stem/progenitor cells (HSPC) and their neoplastic counterparts with their native niches in the human bone marrow. LEPR+ stromal cells are identified as central regulators of hematopoiesis through predicted interactions with all cells in the marrow. Inflammatory niche remodeling and the resulting deprivation of critical HSPC regulatory factors are predicted to repress high-output hematopoietic stem cell subsets in NPM1-mutated acute myeloid leukemia (AML), with relative resistance of clonal cells. Stromal gene signatures reflective of niche remodeling are associated with reduced relapse rates and favorable outcomes after chemotherapy across all genetic risk categories. Elucidation of the intercellular signaling defining human AML, thus, predicts that inflammatory remodeling of stem cell niches drives tissue repression and clonal selection but may pose a vulnerability for relapse-initiating cells in the context of chemotherapeutic treatment.
SIGNIFICANCE
Tumor-promoting inflammation is considered an enabling characteristic of tumorigenesis, but mechanisms remain incompletely understood. By deciphering the predicted signaling between tissue-resident stem cells and their neoplastic counterparts with their environment, we identify inflammatory remodeling of stromal niches as a determinant of normal tissue repression and clinical outcomes in human AML. See related commentary by Lisi-Vega and Méndez-Ferrer, p. 349. This article is featured in Selected Articles from This Issue, p. 337.
Topics: Humans; Hematopoietic Stem Cells; Bone Marrow; Leukemia, Myeloid, Acute; Hematopoiesis; Stromal Cells
PubMed: 37470778
DOI: 10.1158/2643-3230.BCD-23-0043 -
Molecular Cell Jul 2023Histone lysine acylation, including acetylation and crotonylation, plays a pivotal role in gene transcription in health and diseases. However, our understanding of...
Histone lysine acylation, including acetylation and crotonylation, plays a pivotal role in gene transcription in health and diseases. However, our understanding of histone lysine acylation has been limited to gene transcriptional activation. Here, we report that histone H3 lysine 27 crotonylation (H3K27cr) directs gene transcriptional repression rather than activation. Specifically, H3K27cr in chromatin is selectively recognized by the YEATS domain of GAS41 in complex with SIN3A-HDAC1 co-repressors. Proto-oncogenic transcription factor MYC recruits GAS41/SIN3A-HDAC1 complex to repress genes in chromatin, including cell-cycle inhibitor p21. GAS41 knockout or H3K27cr-binding depletion results in p21 de-repression, cell-cycle arrest, and tumor growth inhibition in mice, explaining a causal relationship between GAS41 and MYC gene amplification and p21 downregulation in colorectal cancer. Our study suggests that H3K27 crotonylation signifies a previously unrecognized, distinct chromatin state for gene transcriptional repression in contrast to H3K27 trimethylation for transcriptional silencing and H3K27 acetylation for transcriptional activation.
Topics: Mice; Animals; Chromatin; Histones; Lysine; Transcription Factors; Gene Expression Regulation; Acetylation
PubMed: 37311463
DOI: 10.1016/j.molcel.2023.05.022 -
Annals of the Rheumatic Diseases Nov 2023Prior studies noted that chondrocyte SIRT6 activity is repressed in older chondrocytes rendering cells susceptible to catabolic signalling events implicated in...
OBJECTIVES
Prior studies noted that chondrocyte SIRT6 activity is repressed in older chondrocytes rendering cells susceptible to catabolic signalling events implicated in osteoarthritis (OA). This study aimed to define the effect of deficiency on the development of post-traumatic and age-associated OA in mice.
METHODS
Male cartilage-specific -deficient mice and intact controls underwent destabilisation of the medial meniscus (DMM) or sham surgery at 16 weeks of age and OA severity was analysed at 6 and 10 weeks postsurgery. Age-associated OA was assessed in mice aged 12 and 18 months of age. OA severity was analysed by micro-CT, histomorphometry and scoring of articular cartilage structure, toluidine blue staining and osteophyte formation. SIRT6-regulated pathways were analysed in human chondrocytes by RNA-sequencing, qRT-PCR and immunoblotting.
RESULTS
deficient mice displayed enhanced DMM-induced OA severity and accelerated age-associated OA when compared with controls, characterised by increased cartilage damage, osteophyte formation and subchondral bone sclerosis. In chondrocytes, RNA-sequencing revealed that depletion significantly repressed cartilage extracellular matrix (eg, ) and anabolic growth factor (eg, insulin-like growth factor-1 ()) gene expression. Gain-of-function and loss-of-function studies in chondrocytes demonstrated that SIRT6 depletion attenuated, whereas adenoviral overexpression or MDL-800-induced activation promoted IGF-1 signalling by increasing Akt phosphorylation.
CONCLUSIONS
SIRT6 deficiency increases post-traumatic and age-associated OA severity in vivo. SIRT6 profoundly regulated the pro-anabolic and pro-survival IGF-1/Akt signalling pathway and suggests that preserving the SIRT6/IGF-1/Akt axis may be necessary to protect cartilage from injury-associated or age-associated OA. Targeted therapies aimed at increasing SIRT6 function could represent a novel strategy to slow or stop OA.
Topics: Male; Animals; Mice; Humans; Aged; Insulin-Like Growth Factor I; Osteophyte; Proto-Oncogene Proteins c-akt; Osteoarthritis; Chondrocytes; Cartilage, Articular; RNA; Sirtuins; Disease Models, Animal
PubMed: 37550003
DOI: 10.1136/ard-2023-224385 -
Cell Reports Feb 2024Lactic acid has emerged as an important modulator of immune cell function. It can be produced by both gut microbiota and the host metabolism at homeostasis and during...
Lactic acid has emerged as an important modulator of immune cell function. It can be produced by both gut microbiota and the host metabolism at homeostasis and during disease states. The production of lactic acid in the gut microenvironment is vital for tissue homeostasis. In the present study, we examined how lactic acid integrates cellular metabolism to shape the epigenome of macrophages during pro-inflammatory response. We found that lactic acid serves as a primary fuel source to promote histone H3K27 acetylation, which allows the expression of immunosuppressive gene program including Nr4a1. Consequently, macrophage pro-inflammatory function was transcriptionally repressed. Furthermore, the histone acetylation induced by lactic acid promotes a form of long-term immunosuppression ("trained immunosuppression"). Pre-exposure to lactic acid induces lipopolysaccharide tolerance. These findings thus indicate that lactic acid sensing and its effect on chromatin remodeling in macrophages represent a key homeostatic mechanism that can provide a tolerogenic tissue microenvironment.
Topics: Histones; Acetylation; Gene Expression; Lactic Acid; Macrophages
PubMed: 38329873
DOI: 10.1016/j.celrep.2024.113746