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The escalating obesity epidemic and aging population have propelled metabolic dysfunction-associated steatohepatitis (MASH) to the forefront of public health concerns. The activation of FXR shows promise to combat MASH and its detrimental consequences. However, the specific alterations within the MASH-related transcriptional network remain elusive, hindering the development of more precise and effective therapeutic strategies. Through a comprehensive analysis of liver RNA-seq data from human and mouse MASH samples, we identified central perturbations within the MASH-associated transcriptional network, including disrupted cellular metabolism and mitochondrial function, decreased tissue repair capability, and increased inflammation and fibrosis. By employing integrated transcriptome profiling of diverse FXR agonists-treated mice, FXR liver-specific knockout mice, and open-source human datasets, we determined that hepatic FXR activation effectively ameliorated MASH by reversing the dysregulated metabolic and inflammatory networks implicated in MASH pathogenesis. This mitigation encompassed resolving fibrosis and reducing immune infiltration. By understanding the core regulatory network of FXR, which is directly correlated with disease severity and treatment response, we identified approximately one-third of the patients who could potentially benefit from FXR agonist therapy. A similar analysis involving intestinal RNA-seq data from FXR agonists-treated mice and FXR intestine-specific knockout mice revealed that intestinal FXR activation attenuates intestinal inflammation, and has promise in attenuating hepatic inflammation and fibrosis. Collectively, our study uncovers the intricate pathophysiological features of MASH at a transcriptional level and highlights the complex interplay between FXR activation and both MASH progression and regression. These findings contribute to precise drug development, utilization, and efficacy evaluation, ultimately aiming to improve patient outcomes.
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Cytochrome P450 (CYP) 2Ds are drug metabolizing enzymes found in brain and liver which metabolize numerous centrally acting drugs. Inhibition and induction of CYP2D-mediated metabolism in rodent brain alters brain drug and metabolite concentrations and resulting drug response. In female rats, brain CYP2D metabolism varies across the estrous cycle and with exogenous estrogen, changing brain drug concentrations and response. In this study harmine-induced hypothermia was lower in humanized CYP2D6 transgenic female mice during estrus compared to diestrus. Pretreatment into the cerebral ventricles with propranolol, a selective irreversible inhibitor of human CYP2D6 in brain, increased hypothermia in estrus but not in diestrus. In vivo enzyme activity was higher in brains of transgenic mice in estrus compared to diestrus and was lower after pretreatment with inhibitor in estrus, but not in diestrus. Hepatic activity and plasma harmine concentrations were unaffected by either estrous phase or inhibition of brain CYP2D6. In wild-type female mice, harmine-induced hypothermia was unaffected by either estrous phase or inhibitor pretreatment. Male mice were used as positive controls, where pretreatment with inhibitor increased harmine-induced hypothermia in transgenic but not wild-type, mice. This study provides evidence for female hormone cycle-based regulation of drug metabolism by human CYP2D6 in brain and resulting drug response. This suggests that brain CYP2D6 metabolism may vary, for example, during the menstrual cycle, pregnancy, or menopause, or while taking oral contraceptives or hormone therapy. This variation could contribute to individual differences in response to centrally acting CYP2D6-substrate drugs by altering local brain drug and/or metabolite concentrations.
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Fenofibrate, a peroxisome proliferator-activated receptor α (PPARα) agonist, is widely prescribed for hyperlipidemia management. Recent studies also showed that it has therapeutic potential in various liver diseases. However, its effects on hepatomegaly and liver regeneration and the involved mechanisms remain unclear. Here, the study showed that fenofibrate significantly promoted liver enlargement and regeneration post-partial hepatectomy in mice, which was dependent on hepatocyte-expressed PPARα. Yes-associated protein (YAP) is pivotal in manipulating liver growth and regeneration. We further identified that fenofibrate activated YAP signaling by suppressing its K48-linked ubiquitination, promoting its K63-linked ubiquitination, and enhancing the interaction and transcriptional activity of the YAP-TEAD complex. Pharmacological inhibition of YAP-TEAD interaction using verteporfin or suppression of YAP using AAV Yap shRNA in mice significantly attenuated fenofibrate-induced hepatomegaly. Other factors, such as MYC, KRT23, RAS, and RHOA, might also participate in fenofibrate-promoted hepatomegaly and liver regeneration. These studies demonstrate that fenofibrate-promoted liver enlargement and regeneration are PPARα-dependent and partially through activating the YAP signaling, with clinical implications of fenofibrate as a novel therapeutic agent for promoting liver regeneration.
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The pregnane X receptor (PXR, NR1I2), a xenobiotic-sensing nuclear receptor signaling potentiates ethanol (EtOH)-induced hepatotoxicity in male mice, however, how PXR signaling modulates EtOH-induced hepatotoxicity in female mice is unknown. Wild type (WT) and Pxr-null mice received 5 % EtOH-containing diets or paired-fed control diets for 8 weeks followed by assessment of liver injury, EtOH elimination rates, histology, and changes in gene and protein expression; microarray and bioinformatic analyses were also employed to identify PXR targets in chronic EtOH-induced hepatotoxicity. In WT females, EtOH ingestion significantly increased serum ethanol and alanine aminotransferase (ALT) levels, hepatic Pxr mRNA, constitutive androstane receptor activation, Cyp2b10 mRNA and protein, oxidative stress, endoplasmic stress (phospho-elF2α) and pro-apoptotic (Bax) protein expression. Unexpectedly, EtOH-fed female Pxr-null mice displayed increased EtOH elimination and elevated levels of hepatic acetaldehyde detoxifying aldehyde dehydrogenase 1a1 (Aldh1a1) mRNA and protein, EtOH-metabolizing alcohol dehydrogenase 1 (ADH1), and lipid suppressing microsomal triglyceride transport protein (MTP) protein, aldo-keto reductase 1b7 (Akr1b7) and Cyp2a5 mRNA, but suppressed CYP2B10 protein levels, with evidence of protection against chronic EtOH-induced oxidative stress and hepatotoxicity. While liver injury was not different between the two WT sexes, female sex may suppress EtOH-induced macrovesicular steatosis in the liver. Several genes and pathways important in retinol and steroid hormone biosynthesis, chemical carcinogenesis, and arachidonic acid metabolism were upregulated by EtOH in a PXR-dependent manner in both sexes. Together, these data establish that female Pxr-null mice are resistant to chronic EtOH-induced hepatotoxicity and unravel the PXR-dependent and -independent mechanisms that contribute to EtOH-induced hepatotoxicity.
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PURPOSE: Nonsmokers account for 10% to 13% of all lung cancer cases in the United States. Etiology is attributed to multiple risk factors including exposure to secondhand smoking, asbestos, environmental pollution, and radon, but these exposures are not within the current eligibility criteria for early lung cancer screening by low-dose CT (LDCT). EXPERIMENTAL DESIGN: Urine samples were collected from two independent cohorts comprising 846 participants (exploratory cohort) and 505 participants (validation cohort). The cancer urinary biomarkers, creatine riboside (CR) and N-acetylneuraminic acid (NANA), were analyzed and quantified using liquid chromatography-mass spectrometry to determine if nonsmoker cases can be distinguished from sex and age-matched controls in comparison with tobacco smoker cases and controls, potentially leading to more precise eligibility criteria for LDCT screening. RESULTS: Urinary levels of CR and NANA were significantly higher and comparable in nonsmokers and tobacco smoker cases than population controls in both cohorts. Receiver operating characteristic analysis for combined CR and NANA levels in nonsmokers of the exploratory cohort resulted in better predictive performance with the AUC of 0.94, whereas the validation cohort nonsmokers had an AUC of 0.80. Kaplan-Meier survival curves showed that high levels of CR and NANA were associated with increased cancer-specific death in nonsmokers as well as tobacco smoker cases in both cohorts. CONCLUSIONS: Measuring CR and NANA in urine liquid biopsies could identify nonsmokers at high risk for lung cancer as candidates for LDCT screening and warrant prospective studies of these biomarkers.
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Biomarcadores Tumorais , Neoplasias Pulmonares , não Fumantes , Fumantes , Humanos , Masculino , Neoplasias Pulmonares/urina , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/etiologia , Neoplasias Pulmonares/patologia , Feminino , Biomarcadores Tumorais/urina , Pessoa de Meia-Idade , Biópsia Líquida , Idoso , Prognóstico , não Fumantes/estatística & dados numéricos , Fumantes/estatística & dados numéricos , Estudos de Casos e Controles , Curva ROC , Fumar/efeitos adversos , Fumar/urina , Fumar Tabaco/urina , Fumar Tabaco/efeitos adversosRESUMO
Nuclear hormone receptors exist in dynamic equilibrium between transcriptionally active and inactive complexes dependent on interactions with ligands, proteins, and chromatin. The present studies examined the hypothesis that endogenous ligands activate peroxisome proliferator-activated receptor-ß/δ (PPARß/δ) in keratinocytes. The phorbol ester treatment or HRAS infection of primary keratinocytes increased fatty acids that were associated with enhanced PPARß/δ activity. Fatty acids caused PPARß/δ-dependent increases in chromatin occupancy and the expression of angiopoietin-like protein 4 (Angptl4) mRNA. Analyses demonstrated that stearoyl Co-A desaturase 1 (Scd1) mediates an increase in intracellular monounsaturated fatty acids in keratinocytes that act as PPARß/δ ligands. The activation of PPARß/δ with palmitoleic or oleic acid causes arrest at the G2/M phase of the cell cycle of HRAS-expressing keratinocytes that is not found in similarly treated HRAS-expressing Pparb/d-null keratinocytes. HRAS-expressing Scd1-null mouse keratinocytes exhibit enhanced cell proliferation, an effect that is mitigated by treatment with palmitoleic or oleic acid. Consistent with these findings, the ligand activation of PPARß/δ with GW0742 or oleic acid prevented UVB-induced non-melanoma skin carcinogenesis, an effect that required PPARß/δ. The results from these studies demonstrate that PPARß/δ has endogenous roles in keratinocytes and can be activated by lipids found in diet and cellular components.
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Queratinócitos , PPAR delta , PPAR beta , Estearoil-CoA Dessaturase , Queratinócitos/metabolismo , Queratinócitos/efeitos dos fármacos , PPAR beta/metabolismo , PPAR beta/genética , Animais , Camundongos , Estearoil-CoA Dessaturase/metabolismo , Estearoil-CoA Dessaturase/genética , PPAR delta/metabolismo , PPAR delta/genética , Ácidos Graxos/metabolismo , Proteína 4 Semelhante a Angiopoietina/metabolismo , Proteína 4 Semelhante a Angiopoietina/genética , Humanos , Ácido Oleico/farmacologia , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Ácidos Graxos Monoinsaturados/farmacologia , Ácidos Graxos Monoinsaturados/metabolismo , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/patologiaRESUMO
Aims: Redox signaling plays a key role in skeletal muscle remodeling induced by exercise and prolonged inactivity, but it is unclear which oxidant triggers myofiber hypertrophy due to the lack of strategies to precisely regulate individual oxidants in vivo. In this study, we used tetrathiomolybdate (TM) to dissociate the link between superoxide (O2â¢-) and hydrogen peroxide and thereby to specifically explore the role of O2â¢- in muscle hypertrophy in C2C12 cells and mice. Results: TM can linearly regulate intracellular O2â¢- levels by inhibition of superoxide dismutase 1 (SOD1). A 70% increase in O2â¢- levels in C2C12 myoblast cells and mice is necessary and sufficient for triggering hypertrophy of differentiated myotubes and can enhance exercise performance by more than 50% in mice. SOD1 knockout blocks TM-induced O2â¢- increments and thereby prevents hypertrophy, whereas SOD1 restoration rescues all these effects. Scavenging O2â¢- with antioxidants abolishes TM-induced hypertrophy and the enhancement of exercise performance, whereas the restoration of O2â¢- levels with a O2â¢- generator promotes muscle hypertrophy independent of SOD1 activity. Innovation and Conclusion: These findings suggest that O2â¢- is an endogenous initiator of myofiber hypertrophy and that TM may be used to treat muscle wasting diseases. Our work not only suggests a novel druggable mechanism to increase muscle mass but also provides a tool for precisely regulating O2â¢- levels in vivo.
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The human gut teems with a diverse ecosystem of microbes, yet non-bacterial portions of that community are overlooked in studies of metabolic diseases firmly linked to gut bacteria. Type 2 diabetes mellitus (T2D) is associated with compositional shifts in the gut bacterial microbiome and the mycobiome, the fungal portion of the microbiome. However, whether T2D and/or metformin treatment underpins fungal community changes is unresolved. To differentiate these effects, we curated a gut mycobiome cohort spanning 1,000 human samples across five countries and validated our findings in a murine experimental model. We use Bayesian multinomial logistic normal models to show that T2D and metformin both associate with shifts in the relative abundance of distinct gut fungi. T2D is associated with shifts in the Saccharomycetes and Sordariomycetes fungal classes, while the genera Fusarium and Tetrapisipora most consistently associate with metformin treatment. We confirmed the impact of metformin on individual gut fungi by administering metformin to healthy mice. Thus, metformin and T2D account for subtle, but significant and distinct variation in the gut mycobiome across human populations. This work highlights for the first time that metformin can confound associations of gut fungi with T2D and warrants the need to consider pharmaceutical interventions in investigations of linkages between metabolic diseases and gut microbial inhabitants. IMPORTANCE: This is the largest to-date multi-country cohort characterizing the human gut mycobiome, and the first to investigate potential perturbations in gut fungi from oral pharmaceutical treatment. We demonstrate the reproducible effects of metformin treatment on the human and murine gut mycobiome and highlight a need to consider metformin as a confounding factor in investigations between type 2 diabetes mellitus and the gut microbial ecosystem.
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Diabetes Mellitus Tipo 2 , Fungos , Microbioma Gastrointestinal , Hipoglicemiantes , Metformina , Micobioma , Metformina/farmacologia , Metformina/uso terapêutico , Diabetes Mellitus Tipo 2/microbiologia , Diabetes Mellitus Tipo 2/tratamento farmacológico , Microbioma Gastrointestinal/efeitos dos fármacos , Animais , Humanos , Micobioma/efeitos dos fármacos , Camundongos , Fungos/efeitos dos fármacos , Fungos/classificação , Fungos/isolamento & purificação , Fungos/genética , Hipoglicemiantes/farmacologia , Hipoglicemiantes/uso terapêutico , Masculino , Feminino , Pessoa de Meia-Idade , Camundongos Endogâmicos C57BL , Estudos de CoortesRESUMO
Marine biogeochemical cycles are built on interactions between surface ocean microbes, particularly those connecting phytoplankton primary producers to heterotrophic bacteria. Details of these associations are not well understood, especially in the case of direct influences of bacteria on phytoplankton physiology. Here we catalogue how the presence of three marine bacteria (Ruegeria pomeroyi DSS-3, Stenotrophomonas sp. SKA14 and Polaribacter dokdonensis MED152) individually and uniquely impact gene expression of the picoeukaryotic alga Micromonas commoda RCC 299. We find a dramatic transcriptomic remodelling by M. commoda after 8 h in co-culture, followed by an increase in cell numbers by 56 h compared with the axenic cultures. Some aspects of the algal transcriptomic response are conserved across all three bacterial co-cultures, including an unexpected reduction in relative expression of photosynthesis and carbon fixation pathways. Expression differences restricted to a single bacterium are also observed, with the Flavobacteriia P. dokdonensis uniquely eliciting changes in relative expression of algal genes involved in biotin biosynthesis and the acquisition and assimilation of nitrogen. This study reveals that M. commoda has rapid and extensive responses to heterotrophic bacteria in ways that are generalizable, as well as in a taxon specific manner, with implications for the diversity of phytoplankton-bacteria interactions ongoing in the surface ocean.
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Fotossíntese , Transcriptoma , Fitoplâncton/genética , Fitoplâncton/metabolismo , Clorófitas/genética , Clorófitas/metabolismo , Clorófitas/microbiologia , Bactérias/genética , Bactérias/classificação , Bactérias/metabolismo , Processos Heterotróficos , Água do Mar/microbiologiaRESUMO
Peroxisome proliferator-activated receptor alpha (PPARA) is a ligand-activated transcription factor that is a key mediator of lipid metabolism and metabolic stress in the liver. Accumulating evidence shows that PPARA regulates the expression of various protein coding and non-coding genes that modulate metabolic stress in the liver. CBFA2/RUNX1 partner transcriptional co-repressor 3 (CBFA2T3) is a DNA-binding transcription factor that belongs to the myeloid translocation gene family. Many studies have shown that CBFA2T3 is associated with acute myeloid leukemia. Especially, CBFA2T3-GLIS2 fusion is a chimeric oncogene associated with a poor survival rate in pediatric acute megakaryocytic leukemia. A previous study identified that PPARA activation promoted Cbfa2t3 induction in liver and that Cbfa2t3 may have a modulatory role in metabolic stress. However, the effect of CBFA2T3 gene expression on metabolic stress is not understood. In this study, the PPARA ligand WY14643 activated Cbfa2t3 expression in mouse liver. Glucose tolerance test and insulin tolerance test data showed that insulin resistance is increased in Cbfa2t3-/- mice compared to Cbfa2t3+/+ mice. Hepatic CBFA2T3 modulates heat shock protein family A member 1b and carbonic anhydrase 5a expression. Histology analysis revealed lipid droplet and lipid accumulation in the liver of fasting Cbfa2t3-/- mice but not Cbfa2t3+/+ mice. The expression of lipid accumulation-related genes, such as Cd36, Cidea, and Fabp1, was increased in the liver of fasting Cbfa2t3-/- mice. Especially, basal expression levels of Cidea mRNA were elevated in the liver of Cbfa2t3-/- mice compared to Cbfa2t3+/+ mice. Much higher induction of Cidea mRNA was seen in the liver of Cbfa2t3-/- mice after WY14643 administration. These results indicate that hepatic CBFA2T3 is a PPARA-sensitive gene that may modulate metabolic stress in mouse liver.
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Jejum , Metabolismo dos Lipídeos , Fígado , PPAR alfa , Animais , Metabolismo dos Lipídeos/genética , Fígado/metabolismo , Camundongos , PPAR alfa/metabolismo , PPAR alfa/genética , Masculino , Camundongos Endogâmicos C57BL , Resistência à Insulina , Camundongos Knockout , Pirimidinas/farmacologiaRESUMO
Metabolic dysfunction-associated steatohepatitis (MASH) - previously described as nonalcoholic steatohepatitis (NASH) - is a major driver of liver fibrosis in humans, while liver fibrosis is a key determinant of all-cause mortality in liver disease independent of MASH occurrence. CCAAT/enhancer binding protein α (CEBPA), as a versatile ligand-independent transcriptional factor, has an important function in myeloid cells, and is under clinical evaluation for cancer therapy. CEBPA is also expressed in hepatocytes and regulates glucolipid homeostasis; however, the role of hepatocyte-specific CEBPA in modulating liver fibrosis progression is largely unknown. Here, hepatic CEBPA expression was found to be decreased during MASH progression both in humans and mice, and hepatic CEBPA mRNA was negatively correlated with MASH fibrosis in the human liver. CebpaΔHep mice had markedly enhanced liver fibrosis induced by a high-fat, high-cholesterol, high-fructose diet or carbon tetrachloride. Temporal and spatial hepatocyte-specific CEBPA loss at the progressive stage of MASH in CebpaΔHep,ERT2 mice functionally promoted liver fibrosis. Mechanistically, hepatocyte CEBPA directly repressed Spp1 transactivation to reduce the secretion of osteopontin, a fibrogenesis inducer of hepatic stellate cells. Forced hepatocyte-specific CEBPA expression reduced MASH-associated liver fibrosis. These results demonstrate an important role for hepatocyte-specific CEBPA in liver fibrosis progression, and may help guide the therapeutic discoveries targeting hepatocyte CEBPA for the treatment of liver fibrosis.
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Proteína alfa Estimuladora de Ligação a CCAAT , Hepatopatia Gordurosa não Alcoólica , Humanos , Camundongos , Animais , Hepatócitos/metabolismo , Cirrose Hepática/genética , Cirrose Hepática/metabolismo , Fígado/metabolismo , Hepatopatia Gordurosa não Alcoólica/etiologia , Modelos Animais de DoençasRESUMO
The intestine is critical for not only processing nutrients but also protecting the organism from the environment. These functions are mainly carried out by the epithelium, which is constantly being self-renewed. Many genes and pathways can influence intestinal epithelial cell proliferation. Among them is mTORC1, whose activation increases cell proliferation. Here, we report the first intestinal epithelial cell (IEC)-specific knockout (ΔIEC) of an amino acid transporter capable of activating mTORC1. We show that the transporter, SLC7A5, is highly expressed in mouse intestinal crypt and Slc7a5ΔIEC reduces mTORC1 signaling. Surprisingly, adult Slc7a5ΔIEC intestinal crypts have increased cell proliferation but reduced mature Paneth cells. Goblet cells, the other major secretory cell type in the small intestine, are increased in the crypts but reduced in the villi. Analyses with scRNA-seq and electron microscopy have revealed dedifferentiation of Paneth cells in Slc7a5ΔIEC mice, leading to markedly reduced secretory granules with little effect on Paneth cell number. Thus, SLC7A5 likely regulates secretory cell differentiation to affect stem cell niche and indirectly regulate cell proliferation.
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Sistemas de Transporte de Aminoácidos , Transportador 1 de Aminoácidos Neutros Grandes , Animais , Camundongos , Diferenciação Celular/genética , Proliferação de Células/genética , Transportador 1 de Aminoácidos Neutros Grandes/genética , Alvo Mecanístico do Complexo 1 de Rapamicina/genéticaRESUMO
Obesity is a significant risk factor for several chronic diseases. However, pre-menopausal females are protected against high-fat diet (HFD)-induced obesity and its adverse effects. The pregnane X receptor (PXR, NR1I2), a xenobiotic-sensing nuclear receptor, promotes short-term obesity-associated liver disease only in male mice but not in females. Therefore, the current study investigated the metabolic and pathophysiological effects of a long-term 52-week HFD in female wild-type (WT) and PXR-KO mice and characterized the PXR-dependent molecular pathways involved. After 52 weeks of HFD ingestion, the body and liver weights and several markers of hepatotoxicity were significantly higher in WT mice than in their PXR-KO counterparts. The HFD-induced liver injury in WT female mice was also associated with upregulation of the hepatic mRNA levels of peroxisome proliferator-activated receptor gamma (Pparg), its target genes, fat-specific protein 27 (Fsp27), and the liver-specific Fsp27b involved in lipid accumulation, apoptosis, and inflammation. Notably, PXR-KO mice displayed elevated hepatic Cyp2a5 (anti-obesity gene), aldo-keto reductase 1b7 (Akr1b7), glutathione-S-transferase M3 (Gstm3) (antioxidant gene), and AMP-activated protein kinase (AMPK) levels, contributing to protection against long-term HFD-induced obesity and inflammation. RNA sequencing analysis revealed a general blunting of the transcriptomic response to HFD in PXR-KO compared to WT mice. Pathway enrichment analysis demonstrated enrichment by HFD for several pathways, including oxidative stress and redox pathway, cholesterol biosynthesis, and glycolysis/gluconeogenesis in WT but not PXR-KO mice. In conclusion, this study provides new insights into the molecular mechanisms by which PXR deficiency protects against long-term HFD-induced severe obesity and its adverse effects in female mice.
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Dieta Hiperlipídica , Fígado , Masculino , Feminino , Camundongos , Animais , Receptor de Pregnano X/genética , Receptor de Pregnano X/metabolismo , Dieta Hiperlipídica/efeitos adversos , Camundongos Endogâmicos C57BL , Aumento de Peso , Obesidade/metabolismo , Inflamação/metabolismo , Camundongos KnockoutRESUMO
Intermittent fasting remains a safe and effective strategy to ameliorate various age-related diseases, but its specific mechanisms are not fully understood. Considering that transcription factors (TFs) determine the response to environmental signals, here, we profiled the diurnal expression of 600 samples across four metabolic tissues sampled every 4 over 24 h from mice placed on five different feeding regimens to provide an atlas of TFs in biological space, time, and feeding regimen. Results showed that 1218 TFs exhibited tissue-specific and temporal expression profiles in ad libitum mice, of which 974 displayed significant oscillations at least in one tissue. Intermittent fasting triggered more than 90% (1161 in 1234) of TFs to oscillate somewhere in the body and repartitioned their tissue-specific expression. A single round of fasting generally promoted TF expression, especially in skeletal muscle and adipose tissues, while intermittent fasting mainly suppressed TF expression. Intermittent fasting down-regulated aging pathway and upregulated the pathway responsible for the inhibition of mammalian target of rapamycin (mTOR). Intermittent fasting shifts the diurnal transcriptome atlas of TFs, and mTOR inhibition may orchestrate intermittent fasting-induced health improvements. This atlas offers a reference and resource to understand how TFs and intermittent fasting may contribute to diurnal rhythm oscillation and bring about specific health benefits.
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Bacteria in the gastrointestinal tract produce amino acid bile acid amidates that can affect host-mediated metabolic processes1-6; however, the bacterial gene(s) responsible for their production remain unknown. Herein, we report that bile salt hydrolase (BSH) possesses dual functions in bile acid metabolism. Specifically, we identified a previously unknown role for BSH as an amine N-acyltransferase that conjugates amines to bile acids, thus forming bacterial bile acid amidates (BBAAs). To characterize this amine N-acyltransferase BSH activity, we used pharmacological inhibition of BSH, heterologous expression of bsh and mutants in Escherichia coli and bsh knockout and complementation in Bacteroides fragilis to demonstrate that BSH generates BBAAs. We further show in a human infant cohort that BBAA production is positively correlated with the colonization of bsh-expressing bacteria. Lastly, we report that in cell culture models, BBAAs activate host ligand-activated transcription factors including the pregnane X receptor and the aryl hydrocarbon receptor. These findings enhance our understanding of how gut bacteria, through the promiscuous actions of BSH, have a significant role in regulating the bile acid metabolic network.
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Aciltransferases , Amidoidrolases , Aminas , Ácidos e Sais Biliares , Biocatálise , Microbioma Gastrointestinal , Humanos , Aciltransferases/metabolismo , Amidoidrolases/metabolismo , Aminas/química , Aminas/metabolismo , Bacteroides fragilis/enzimologia , Bacteroides fragilis/genética , Bacteroides fragilis/metabolismo , Ácidos e Sais Biliares/química , Ácidos e Sais Biliares/metabolismo , Estudos de Coortes , Escherichia coli/enzimologia , Escherichia coli/genética , Escherichia coli/metabolismo , Microbioma Gastrointestinal/fisiologia , Ligantes , Receptor de Pregnano X/metabolismo , Receptores de Hidrocarboneto Arílico/metabolismo , Fatores de Transcrição/metabolismo , Lactente , Técnicas de Cultura de CélulasRESUMO
Hepatocyte nuclear factor 4A (HNF4A/NR2a1), a transcriptional regulator of hepatocyte identity, controls genes that are crucial for liver functions, primarily through binding to enhancers. In mammalian cells, active and primed enhancers are marked by monomethylation of histone 3 (H3) at lysine 4 (K4) (H3K4me1) in a cell type-specific manner. How this modification is established and maintained at enhancers in connection with transcription factors (TFs) remains unknown. Using analysis of genome-wide histone modifications, TF binding, chromatin accessibility and gene expression, we show that HNF4A is essential for an active chromatin state. Using HNF4A loss and gain of function experiments in vivo and in cell lines in vitro, we show that HNF4A affects H3K4me1, H3K27ac and chromatin accessibility, highlighting its contribution to the establishment and maintenance of a transcriptionally permissive epigenetic state. Mechanistically, HNF4A interacts with the mixed-lineage leukaemia 4 (MLL4) complex facilitating recruitment to HNF4A-bound regions. Our findings indicate that HNF4A enriches H3K4me1, H3K27ac and establishes chromatin opening at transcriptional regulatory regions.
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Elementos Facilitadores Genéticos , Leucemia , Animais , Histonas/genética , Histonas/metabolismo , Cromatina/genética , Histona-Lisina N-Metiltransferase/genética , Histona-Lisina N-Metiltransferase/metabolismo , Mamíferos/genéticaRESUMO
INTRODUCTION: Uterine fibroids affect 30%-77% of reproductive-age women and are a significant cause of infertility. Surgical myomectomies can restore fertility, but they often have limited and temporary benefits, with postoperative complications such as adhesions negatively impacting fertility. Existing medical therapies, such as oral contraceptives, gonadotropin hormone-releasing hormone (GnRH) analogues and GnRH antagonists, can manage fibroid symptoms but are not fertility friendly. This study addresses the pressing need for non-hormonal, non-surgical treatment options for women with fibroids desiring pregnancy. Previous preclinical and clinical studies have shown that epigallocatechin gallate (EGCG) effectively reduces uterine fibroid size. We hypothesise that EGCG from green tea extract will shrink fibroids, enhance endometrial quality and increase pregnancy likelihood. To investigate this hypothesis, we initiated a National Institute of Child Health and Human Development Confirm-funded trial to assess EGCG's efficacy in treating women with fibroids and unexplained infertility. METHODS AND ANALYSIS: This multicentre, prospective, interventional, randomised, double-blinded clinical trial aims to enrol 200 participants with fibroids and unexplained infertility undergoing intrauterine insemination (IUI). Participants will be randomly assigned in a 3:1 ratio to two groups: green tea extract (1650 mg daily) or a matched placebo, combined with clomiphene citrate-induced ovarian stimulation and timed IUI for up to four cycles. EGCG constitutes approximately 45% of the green tea extract. The primary outcome is the cumulative live birth rate, with secondary outcomes including conception rate, time to conception, miscarriage rate, change in fibroid volume and symptom severity scores and health-related quality of life questionnaire scores. ETHICS AND DISSEMINATION: The FRIEND trial received approval from the Food and Drug adminstration (FDA) (investigational new drug number 150951), the central Institutional Review Board (IRB) at Johns Hopkins University and FRIEND-collaborative site local IRBs. The data will be disseminated at major conferences, published in peer-reviewed journals and support a large-scale clinical trial. TRIAL REGISTRATION NUMBER: NCT05364008.
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Catequina/análogos & derivados , Infertilidade , Leiomioma , Gravidez , Criança , Feminino , Humanos , Chá , Qualidade de Vida , Estudos Prospectivos , Leiomioma/complicações , Leiomioma/tratamento farmacológico , Leiomioma/cirurgia , Infertilidade/terapia , Fertilidade , Indução da Ovulação/métodos , Hormônio Liberador de Gonadotropina/uso terapêutico , Taxa de Gravidez , Ensaios Clínicos Controlados Aleatórios como Assunto , Estudos Multicêntricos como AssuntoRESUMO
Aspirin-related gastrointestinal damage is of growing concern. Aspirin use modulates the gut microbiota and associated metabolites, such as bile acids (BAs), but how this impacts intestinal homeostasis remains unclear. Herein, using clinical cohorts and aspirin-treated mice, we identified an intestinal microbe, Parabacteroides goldsteinii, whose growth is suppressed by aspirin. Mice supplemented with P. goldsteinii or its BA metabolite, 7-keto-lithocholic acid (7-keto-LCA), showed reduced aspirin-mediated damage of the intestinal niche and gut barrier, effects that were lost with a P. goldsteinii hdhA mutant unable to generate 7-keto-LCA. Specifically, 7-keto-LCA promotes repair of the intestinal epithelium by suppressing signaling by the intestinal BA receptor, farnesoid X receptor (FXR). 7-Keto-LCA was confirmed to be an FXR antagonist that facilitates Wnt signaling and thus self-renewal of intestinal stem cells. These results reveal the impact of oral aspirin on the gut microbiota and intestinal BA metabolism that in turn modulates gastrointestinal homeostasis.
Assuntos
Aspirina , Microbioma Gastrointestinal , Camundongos , Animais , Aspirina/farmacologia , Ácidos e Sais Biliares , Receptores Citoplasmáticos e Nucleares , HomeostaseRESUMO
Determining the structure and phenotypic context of molecules detected in untargeted metabolomics experiments remains challenging. Here we present reverse metabolomics as a discovery strategy, whereby tandem mass spectrometry spectra acquired from newly synthesized compounds are searched for in public metabolomics datasets to uncover phenotypic associations. To demonstrate the concept, we broadly synthesized and explored multiple classes of metabolites in humans, including N-acyl amides, fatty acid esters of hydroxy fatty acids, bile acid esters and conjugated bile acids. Using repository-scale analysis1,2, we discovered that some conjugated bile acids are associated with inflammatory bowel disease (IBD). Validation using four distinct human IBD cohorts showed that cholic acids conjugated to Glu, Ile/Leu, Phe, Thr, Trp or Tyr are increased in Crohn's disease. Several of these compounds and related structures affected pathways associated with IBD, such as interferon-γ production in CD4+ T cells3 and agonism of the pregnane X receptor4. Culture of bacteria belonging to the Bifidobacterium, Clostridium and Enterococcus genera produced these bile amidates. Because searching repositories with tandem mass spectrometry spectra has only recently become possible, this reverse metabolomics approach can now be used as a general strategy to discover other molecules from human and animal ecosystems.
Assuntos
Amidas , Ácidos e Sais Biliares , Ésteres , Ácidos Graxos , Metabolômica , Animais , Humanos , Bifidobacterium/metabolismo , Ácidos e Sais Biliares/química , Ácidos e Sais Biliares/metabolismo , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Clostridium/metabolismo , Estudos de Coortes , Doença de Crohn/metabolismo , Enterococcus/metabolismo , Ésteres/química , Ésteres/metabolismo , Ácidos Graxos/química , Ácidos Graxos/metabolismo , Doenças Inflamatórias Intestinais/metabolismo , Metabolômica/métodos , Fenótipo , Receptor de Pregnano X/metabolismo , Reprodutibilidade dos Testes , Espectrometria de Massas em Tandem , Amidas/química , Amidas/metabolismoRESUMO
Fuchs endothelial corneal dystrophy (FECD) is a genetically complex, age-related, female-predominant disorder characterized by loss of post-mitotic corneal endothelial cells (CEnCs). Ultraviolet-A (UVA) light has been shown to recapitulate the morphological and molecular changes seen in FECD to a greater extent in females than males, by triggering CYP1B1 upregulation in females. Herein, we investigated the mechanism of greater CEnC susceptibility to UVA in females by studying estrogen metabolism in response to UVA in the cornea. Loss of NAD(P)H quinone oxidoreductase 1 (NQO1) resulted in increased production of estrogen metabolites and mitochondrial-DNA adducts, with a higher CEnC loss in Nqo1-/- female compared to wild-type male and female mice. The CYP1B1 inhibitors, trans-2,3',4,5'-tetramethoxystilbene (TMS) and berberine, rescued CEnC loss. Injection of wild-type male mice with estrogen (E2; 17ß-estradiol) increased CEnC loss, followed by increased production of estrogen metabolites and mitochondrial DNA (mtDNA) damage, not seen in E2-treated Cyp1b1-/-male mice. This study demonstrates that the endo-degenerative phenotype is driven by estrogen metabolite-dependent CEnC loss that is exacerbated in the absence of NQO1; thus, explaining the mechanism accounting for the higher incidence of FECD in females. The mitigation of estrogen-adduct production by CYP1B1 inhibitors could serve as a novel therapeutic strategy for FECD.