RESUMEN
Intraepithelial lymphocytes (IELs) are T cells important for the maintenance of barrier integrity in the intestine. Colon IELs are significantly reduced in both MyD88-deficient mice and those lacking an intact microbiota, suggesting that MyD88-mediated detection of bacterial products is important for the recruitment and/or retention of these cells. Here, using conditionally deficient MyD88 mice, we show that myeloid cells are the key mediators of TCRαß+ IEL recruitment to the colon. Upon exposure to luminal bacteria, myeloid cells produce sphingosine-1-phosphate (S1P) in a MyD88-dependent fashion. TCRαß+ IEL recruitment may be blocked using the S1P receptor antagonist FTY720, confirming the importance of S1P in the recruitment of TCRαß+ IELs to the colon epithelium. Finally, using the TNFΔARE/+ model of Crohn's-like bowel inflammation, we show that disruption of colon IEL recruitment through myeloid-specific MyD88 deficiency results in reduced pathology. Our results illustrate one mechanism for recruitment of a subset of IELs to the colon.
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Colon , Mucosa Intestinal , Linfocitos Intraepiteliales , Lisofosfolípidos , Ratones Noqueados , Células Mieloides , Factor 88 de Diferenciación Mieloide , Receptores de Antígenos de Linfocitos T alfa-beta , Esfingosina , Animales , Lisofosfolípidos/metabolismo , Ratones , Esfingosina/análogos & derivados , Esfingosina/metabolismo , Colon/inmunología , Factor 88 de Diferenciación Mieloide/metabolismo , Células Mieloides/inmunología , Células Mieloides/metabolismo , Mucosa Intestinal/inmunología , Mucosa Intestinal/metabolismo , Linfocitos Intraepiteliales/inmunología , Linfocitos Intraepiteliales/metabolismo , Receptores de Antígenos de Linfocitos T alfa-beta/metabolismo , Receptores de Antígenos de Linfocitos T alfa-beta/genética , Ratones Endogámicos C57BL , Clorhidrato de Fingolimod/farmacología , Enfermedad de Crohn/inmunologíaRESUMEN
BACKGROUND AND AIMS: Chronic liver disease due to metabolic dysfunction-associated steatohepatitis (MASH) is a rapidly increasing global epidemic. MASH progression is a consequence of the complex interplay between inflammatory insults and dysregulated hepatic immune responses. T lymphocytes have been shown to accumulate in the liver during MASH, but the cause and consequence of T cell accumulation in the liver remain unclear. Our study aimed to define the phenotype and T cell receptor diversity of T cells from human cirrhotic livers and an animal model of MASH to begin resolving their function in disease. APPROACH AND RESULTS: In these studies, we evaluated differences in T cell phenotype in the context of liver disease. Accordingly, we isolated liver resident T cell populations from humans with cirrhosis and from mice with diet-induced MASH. Using both 5' single-cell sequencing and flow cytometry, we defined the phenotype and T cell receptor repertoire of liver resident T cells during health and disease. CONCLUSIONS: MASH-induced human cirrhosis and diet-induced MASH in mice resulted in the accumulation of activated and clonally expanded T cells in the liver. The clonally expanded T cells in the liver expressed markers of chronic antigenic stimulation, including PD1, TIGIT, and TOX. Overall, this study establishes for the first time that T cells undergo Ag-dependent clonal expansion and functional differentiation during the progression of MASH. These studies could lead to the identification of antigenic targets that drive T cell activation, clonal expansion, and recruitment to the liver during MASH.
RESUMEN
Cystathionine beta-synthase-deficient homocystinuria (HCU) is a life-threatening disorder of sulfur metabolism. HCU can be treated by using betaine to lower tissue and plasma levels of homocysteine (Hcy). Here, we show that mice with severely elevated Hcy and potentially deficient in the folate species tetrahydrofolate (THF) exhibit a very limited response to betaine indicating that THF plays a critical role in treatment efficacy. Analysis of a mouse model of HCU revealed a 10-fold increase in hepatic levels of 5-methyl -THF and a 30-fold accumulation of formiminoglutamic acid, consistent with a paucity of THF. Neither of these metabolite accumulations were reversed or ameliorated by betaine treatment. Hepatic expression of the THF-generating enzyme dihydrofolate reductase (DHFR) was significantly repressed in HCU mice and expression was not increased by betaine treatment but appears to be sensitive to cellular redox status. Expression of the DHFR reaction partner thymidylate synthase was also repressed and metabolomic analysis detected widespread alteration of hepatic histidine and glutamine metabolism. Many individuals with HCU exhibit endothelial dysfunction. DHFR plays a key role in nitric oxide (NO) generation due to its role in regenerating oxidized tetrahydrobiopterin, and we observed a significant decrease in plasma NOx (NO2 + NO3) levels in HCU mice. Additional impairment of NO generation may also come from the HCU-mediated induction of the 20-hydroxyeicosatetraenoic acid generating cytochrome CYP4A. Collectively, our data shows that HCU induces dysfunctional one-carbon metabolism with the potential to both impair betaine treatment and contribute to multiple aspects of pathogenesis in this disease.
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Homocistinuria , Hígado , Oxidación-Reducción , Tetrahidrofolato Deshidrogenasa , Tetrahidrofolatos , Animales , Homocistinuria/metabolismo , Homocistinuria/tratamiento farmacológico , Homocistinuria/genética , Ratones , Tetrahidrofolatos/metabolismo , Hígado/metabolismo , Tetrahidrofolato Deshidrogenasa/metabolismo , Tetrahidrofolato Deshidrogenasa/genética , Betaína/metabolismo , Betaína/farmacología , Homocisteína/metabolismo , Ratones Endogámicos C57BL , Cistationina betasintasa/metabolismo , Cistationina betasintasa/genética , Carbono/metabolismo , Masculino , Ácido Fólico/metabolismo , FemeninoRESUMEN
Hepatic innate immune function plays an important role in the pathogenesis of many diseases. Importantly, a growing body of literature has firmly established the spatial heterogeneity of hepatocyte metabolic function; however, whether innate immune function is zonated remains unknown. To test this question, we exposed adult C57BL/6 mice to endotoxemia, and hepatic tissue was assessed for the acute phase response (APR). The zone-specific APR was evaluated in periportal and pericentral/centrilobular hepatocytes isolated using digitonin perfusion and on hepatic tissue using RNAscope and immunohistochemistry. Western blot, EMSA, chromatin immunoprecipitation, and immunohistochemistry were used to determine the role of the transcription factor NF-κB in mediating hepatic C-reactive protein (CRP) expression. Finally, the ability of mice lacking the NF-κB subunit p50 (p50-/-) to raise a hepatic APR was evaluated. We found that endotoxemia induces a hepatocyte transcriptional APR in both male and female mice, with Crp, Apcs, Fga, Hp, and Lbp expression being enriched in pericentral/centrilobular hepatocytes. Focusing our work on CRP expression, we determined that NF-κB transcription factor subunit p50 binds to consensus sequence elements present in the murine CRP promoter. Furthermore, pericentral/centrilobular hepatocyte p50 nuclear translocation is temporally associated with zone-specific APR during endotoxemia. Lastly, the APR and CRP expression is blunted in endotoxemic p50-/- mice. These results demonstrate that the murine hepatocyte innate immune response to endotoxemia includes zone-specific activation of transcription factors and target gene expression. These results support further study of zone-specific hepatocyte innate immunity and its role in the development of various disease states.
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Endotoxemia , FN-kappa B , Masculino , Femenino , Animales , Ratones , FN-kappa B/metabolismo , Proteína C-Reactiva/metabolismo , Ratones Endogámicos C57BL , Hígado/metabolismo , Subunidad p50 de NF-kappa B/metabolismo , Inmunidad InnataRESUMEN
BACKGROUND: The developmental immaturity of the innate immune system helps explains the increased risk of infection in the neonatal period. Importantly, innate immune signaling pathways such as p65/NFκB and c-Jun/AP1 are responsible for the prevention of hepatocyte apoptosis in adult animals, yet whether developmental immaturity of these pathways increases the risk of hepatic injury in the neonatal period is unknown. METHODS: Using a murine model of endotoxemia (LPS 5 mg/kg IP x 1) in neonatal (P3) and adult mice, we evaluated histologic evidence of hepatic injury and apoptosis, presence of p65/NFκB and c-Jun/AP1 activation and associated transcriptional regulation of apoptotic genes. RESULTS: We demonstrate that in contrast to adults, endotoxemic neonatal (P3) mice exhibit a significant increase in hepatic apoptosis. This is associated with absent hepatic p65/NFκB signaling and impaired expression of anti-apoptotic target genes. Hepatic c-Jun/AP1 activity was attenuated in endotoxemic P3 mice, with resulting upregulation of pro-apoptotic factors. CONCLUSIONS: These results demonstrate that developmental absence of innate immune p65/NFκB and c-Jun/AP1 signaling, and target gene expression is associated with apoptotic injury in neonatal mice. More work is needed to determine if this contributes to long-term hepatic dysfunction, and whether immunomodulatory approaches can prevent this injury. IMPACT: Various aspects of developmental immaturity of the innate immune system may help explain the increased risk of infection in the neonatal period. In adult models of inflammation and infection, innate immune signaling pathways such as p65/NFκB and c-Jun/AP1 are responsible for a protective, pro-inflammatory transcriptome and regulation of apoptosis. We demonstrate that in contrast to adults, endotoxemic neonatal (P3) mice exhibit a significant increase in hepatic apoptosis associated with absent hepatic p65/NFκB signaling and c-Jun/AP1 activity. We believe that these results may explain in part hepatic dysfunction with neonatal sepsis, and that there may be unrecognized developmental and long-term hepatic implications of early life exposure to systemic inflammatory stress.
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Animales Recién Nacidos , Apoptosis , Endotoxemia , Inmunidad Innata , Hígado , Transducción de Señal , Factor de Transcripción AP-1 , Animales , Factor de Transcripción AP-1/metabolismo , Hígado/metabolismo , Hígado/inmunología , Hígado/patología , Ratones , Endotoxemia/inmunología , Endotoxemia/metabolismo , FN-kappa B/metabolismo , Factor de Transcripción ReIA/metabolismo , Lipopolisacáridos , Ratones Endogámicos C57BL , Proteínas Proto-Oncogénicas c-jun/metabolismo , Modelos Animales de EnfermedadRESUMEN
Hibernation is a natural model of extreme physiology in a mammal. Throughout winter, small hibernators repeatedly undergo rapid, dramatic swings in body temperature, perfusion, and oxygen delivery. To gain insight into the molecular mechanisms that support homeostasis despite the numerous challenges posed by this dynamic physiology, we collected 13-lined ground squirrel adrenal glands from at least five individuals representing six key timepoints across the year using body temperature telemetry. Differentially expressed genes were identified using RNA-seq, revealing both strong seasonal and torpor-arousal cycle effects on gene expression. Two novel findings emerge from this study. First, transcripts encoding multiple genes involved in steroidogenesis decreased seasonally. Taken together with morphometric analyses, the data are consistent with preservation of mineralocorticoids but suppression of glucocorticoid and androgen output throughout winter hibernation. Second, a temporally orchestrated, serial gene expression program unfolds across the brief arousal periods. This program initiates during early rewarming with the transient activation of a set of immediate early response (IER) genes, comprised of both transcription factors and the RNA degradation proteins that assure their rapid turnover. This pulse in turn activates a cellular stress response program to restore proteostasis comprised of protein turnover, synthesis, and folding machinery. These and other data support a general model for gene expression across the torpor-arousal cycle that is facilitated in synchrony with whole body temperature shifts; induction of the immediate early response upon rewarming activates a proteostasis program followed by a restored tissue-specific gene expression profile enabling renewal, repair, and survival of the torpid state.NEW & NOTEWORTHY This pioneer study of adrenal gland gene expression dynamics in hibernating ground squirrels leverages the power of RNA-seq on multiple precisely timed samples to demonstrate: 1) steroidogenesis is seasonally reorganized to preserve aldosterone at the expense of glucocorticoids and androgens throughout winter hibernation; 2) a serial gene expression program unfolds during each short arousal whereby immediate early response genes induce the gene expression machinery that restores proteostasis and the cell-specific expression profile before torpor reentry.
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Hibernación , Letargo , Humanos , Animales , Hibernación/genética , Letargo/genética , Mamíferos/genética , Expresión Génica , Sciuridae/fisiologíaRESUMEN
Nonalcoholic steatohepatitis (NASH) is the most common chronic liver disease in the US, partly due to the increasing incidence of metabolic syndrome, obesity, and type 2 diabetes. The roles of bile acids and their receptors, such as the nuclear receptor farnesoid X receptor (FXR) and the G protein-coupled receptor TGR5, on the development of NASH are not fully clear. C57BL/6J male mice fed a Western diet (WD) develop characteristics of NASH, allowing determination of the effects of FXR and TGR5 agonists on this disease. Here we show that the FXR-TGR5 dual agonist INT-767 prevents progression of WD-induced hepatic steatosis, inflammation, and fibrosis, as determined by histological and biochemical assays and novel label-free microscopy imaging techniques, including third harmonic generation, second harmonic generation, and fluorescence lifetime imaging microscopy. Furthermore, we show INT-767 decreases liver fatty acid synthesis and fatty acid and cholesterol uptake, as well as liver inflammation. INT-767 markedly changed bile acid composition in the liver and intestine, leading to notable decreases in the hydrophobicity index of bile acids, known to limit cholesterol and lipid absorption. In addition, INT-767 upregulated expression of liver p-AMPK, SIRT1, PGC-1α, and SIRT3, which are master regulators of mitochondrial function. Finally, we found INT-767 treatment reduced WD-induced dysbiosis of gut microbiota. Interestingly, the effects of INT-767 in attenuating NASH were absent in FXR-null mice, but still present in TGR5-null mice. Our findings support treatment and prevention protocols with the dual FXR-TGR5 agonist INT-767 arrest progression of WD-induced NASH in mice mediated by FXR-dependent, TGR5-independent mechanisms.
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Diabetes Mellitus Tipo 2 , Enfermedad del Hígado Graso no Alcohólico , Animales , Masculino , Ratones , Ácidos y Sales Biliares , Colesterol/metabolismo , Diabetes Mellitus Tipo 2/complicaciones , Dieta Occidental , Ácidos Grasos , Fibrosis , Inflamación/complicaciones , Ratones Endogámicos C57BL , Ratones Noqueados , Enfermedad del Hígado Graso no Alcohólico/metabolismo , Receptores Acoplados a Proteínas G/metabolismoRESUMEN
Prerenal azotemia (PRA) is a major cause of acute kidney injury and uncommonly studied in preclinical models. We sought to develop and characterize a novel model of PRA that meets the clinical definition: acute loss of glomerular filtration rate (GFR) that returns to baseline with resuscitation. Adult male C57BL/6J wild-type (WT) and IL-6-/- mice were studied. Intraperitoneal furosemide (4 mg) or vehicle was administered at time = 0 and 3 h to induce PRA from volume loss. Resuscitation began at 6 h with 1 mL intraperitoneal saline for four times for 36 h. Six hours after furosemide administration, measured glomerular filtration rate was 25% of baseline and returned to baseline after saline resuscitation at 48 h. After 6 h of PRA, plasma interleukin (IL)-6 was significantly increased, kidney and liver histology were normal, kidney and liver lactate were normal, and kidney injury molecule-1 immunofluorescence was negative. There were 327 differentially regulated genes upregulated in the liver, and the acute phase response was the most significantly upregulated pathway; 84 of the upregulated genes (25%) were suppressed in IL-6-/- mice, and the acute phase response was the most significantly suppressed pathway. Significantly upregulated genes and their proteins were also investigated and included serum amyloid A2, serum amyloid A1, lipocalin 2, chemokine (C-X-C motif) ligand 1, and haptoglobin; hepatic gene expression and plasma protein levels were all increased in wild-type PRA and were all reduced in IL-6-/- PRA. This work demonstrates previously unknown systemic effects of PRA that includes IL-6-mediated upregulation of the hepatic acute phase response.NEW & NOTEWORTHY Prerenal azotemia (PRA) accounts for a third of acute kidney injury (AKI) cases yet is rarely studied in preclinical models. We developed a clinically defined murine model of prerenal azotemia characterized by a 75% decrease in measured glomerular filtration rate (GFR), return of measured glomerular filtration rate to baseline with resuscitation, and absent tubular injury. Numerous systemic effects were observed, such as increased plasma interleukin-6 (IL-6) and upregulation of the hepatic acute phase response.
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Lesión Renal Aguda , Azotemia , Animales , Masculino , Ratones , Lesión Renal Aguda/metabolismo , Reacción de Fase Aguda/complicaciones , Azotemia/complicaciones , Biomarcadores , Modelos Animales de Enfermedad , Furosemida , Tasa de Filtración Glomerular/fisiología , Interleucina-6/genética , Interleucina-6/metabolismo , Lipocalina 2/genética , Hígado/metabolismo , Ratones Endogámicos C57BLRESUMEN
BACKGROUND AND AIMS: Parenteral nutrition (PN)-associated cholestasis (PNAC) complicates the care of patients with intestinal failure. In PNAC, phytosterol containing PN synergizes with intestinal injury and IL-1ß derived from activated hepatic macrophages to suppress hepatocyte farnesoid X receptor (FXR) signaling and promote PNAC. We hypothesized that pharmacological activation of FXR would prevent PNAC in a mouse model. APPROACH AND RESULTS: To induce PNAC, male C57BL/6 mice were subjected to intestinal injury (2% dextran sulfate sodium [DSS] for 4 days) followed by central venous catheterization and 14-day infusion of PN with or without the FXR agonist GW4064. Following sacrifice, hepatocellular injury, inflammation, and biliary and sterol transporter expression were determined. GW4064 (30 mg/kg/day) added to PN on days 4-14 prevented hepatic injury and cholestasis; reversed the suppressed mRNA expression of nuclear receptor subfamily 1, group H, member 4 (Nr1h4)/FXR, ATP-binding cassette subfamily B member 11 (Abcb11)/bile salt export pump, ATP-binding cassette subfamily C member 2 (Abcc2), ATP binding cassette subfamily B member 4(Abcb4), and ATP-binding cassette subfamily G members 5/8(Abcg5/8); and normalized serum bile acids. Chromatin immunoprecipitation of liver showed that GW4064 increased FXR binding to the Abcb11 promoter. Furthermore, GW4064 prevented DSS-PN-induced hepatic macrophage accumulation, hepatic expression of genes associated with macrophage recruitment and activation (ll-1b, C-C motif chemokine receptor 2, integrin subunit alpha M, lymphocyte antigen 6 complex locus C), and hepatic macrophage cytokine transcription in response to lipopolysaccharide in vitro. In primary mouse hepatocytes, GW4064 activated transcription of FXR canonical targets, irrespective of IL-1ß exposure. Intestinal inflammation and ileal mRNAs (Nr1h4, Fgf15, and organic solute transporter alpha) were not different among groups, supporting a liver-specific effect of GW4064 in this model. CONCLUSIONS: GW4064 prevents PNAC in mice through restoration of hepatic FXR signaling, resulting in increased expression of canalicular bile and of sterol and phospholipid transporters and suppression of macrophage recruitment and activation. These data support augmenting FXR activity as a therapeutic strategy to alleviate or prevent PNAC.
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Colestasis/prevención & control , Expresión Génica/efectos de los fármacos , Isoxazoles/farmacología , Nutrición Parenteral/efectos adversos , Receptores Citoplasmáticos y Nucleares/agonistas , Receptores Citoplasmáticos y Nucleares/genética , Miembro 11 de la Subfamilia B de Transportador de Casetes de Unión al ATP/genética , Miembro 11 de la Subfamilia B de Transportador de Casetes de Unión al ATP/metabolismo , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 5/genética , Transportador de Casete de Unión a ATP, Subfamilia G, Miembro 8/genética , Animales , Ácidos y Sales Biliares/sangre , Colestasis/etiología , Regulación de la Expresión Génica/efectos de los fármacos , Hepatocitos/metabolismo , Interleucina-1beta/farmacología , Enfermedades Intestinales/inducido químicamente , Enfermedades Intestinales/terapia , Isoxazoles/uso terapéutico , Lipoproteínas/genética , Hepatopatías/etiología , Hepatopatías/patología , Hepatopatías/prevención & control , Activación de Macrófagos/efectos de los fármacos , Macrófagos/patología , Masculino , Ratones , Ratones Endogámicos C57BL , Proteína 2 Asociada a Resistencia a Múltiples Medicamentos/genética , Proteínas Asociadas a Resistencia a Múltiples Medicamentos/genética , ARN Mensajero/metabolismo , Receptores Citoplasmáticos y Nucleares/metabolismo , Transducción de Señal/efectos de los fármacosRESUMEN
Hepatocellular carcinoma (HCC) is a major global health concern, representing one of the leading causes of cancer-related deaths. Despite various treatment options, the prognosis for HCC patients remains poor, emphasizing the need for a deeper understanding of the factors contributing to HCC development. This study investigates the role of poly(ADP-ribosyl)ation in hepatocyte maturation and its impact on hepatobiliary carcinogenesis. A conditional Parg knockout mouse model was employed, utilizing Cre recombinase under the albumin promoter to target Parg depletion specifically in hepatocytes. The disruption of the poly(ADP-ribosyl)ating pathway in hepatocytes affects the early postnatal liver development. The inability of hepatocytes to finish the late maturation step that occurs early after birth causes intensive apoptosis and acute inflammation, resulting in hypertrophic liver tissue with enlarged hepatocytes. Regeneration nodes with proliferative hepatocytes eventually replace the liver tissue and successfully fulfill the liver function. However, early developmental changes predispose these types of liver to develop pathologies, including with a malignant nature, later in life. In a chemically induced liver cancer model, Parg-depleted livers displayed a higher tendency for hepatocellular carcinoma development. This study underscores the critical role of the poly(ADP-ribosyl)ating pathway in hepatocyte maturation and highlights its involvement in liver pathologies and hepatobiliary carcinogenesis. Understanding these processes may provide valuable insights into liver biology and liver-related diseases, including cancer.
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Carcinoma Hepatocelular , Neoplasias Hepáticas , Lesiones Precancerosas , Animales , Ratones , Humanos , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Hepatocitos/metabolismo , Lesiones Precancerosas/metabolismo , Carcinogénesis/genética , Carcinogénesis/metabolismo , Glicósido Hidrolasas/metabolismo , Poli Adenosina Difosfato Ribosa/metabolismo , Mamíferos/metabolismoRESUMEN
The factors (environmental and genetic) contributing to basal cell carcinoma (BCC) pathogenesis are well-established; however, effective agents for BCC prevention are marred by toxic side-effects. Herein, we assessed the efficacy of flavonolignan silibinin against ultraviolet B (UVB)-induced BCC in Ptch+/- (heterozygous patched homolog 1 gene) mouse model. Both male and female Ptch+/- mice were irradiated with a 240 mJ/cm2 UVB dose 3 times/week for 26 or 46 weeks, with or without topical application of silibinin (9 mg/200 µl in acetone, applied 30 min before or after UVB exposure). Results indicated that silibinin application either pre- or post-UVB exposure for 26 weeks significantly decreased the number of BCC lesions by 65% and 39% (P < 0.001 for both) and the area covered by BCCs (72% and 45%, P < 0.001 for both), respectively, compared to UVB alone. Furthermore, continuous UVB exposure for 46 weeks increased the BCC lesion number and the BCC area covered by ~6 and ~3.4 folds (P < 0.001), respectively. Notably, even in this 46 week prolonged UVB exposure, silibinin (irrespective of pre- or post-UVB treatment) significantly halted the growth of BCCs by 81-94% (P < 0.001) as well as other epidermal lesions; specifically, silibinin treated tissues had less epidermal dysplasia, fibrosarcoma, and squamous cell carcinoma. Immunohistochemistry and immunofluorescence studies revealed that silibinin significantly decreased basal cell proliferation (Ki-67) and the expression of cytokeratins (14 and 15), and Hedgehog signaling mediators Smo and Gli1 in the BCC lesions. Together, our findings demonstrate strong potential of silibinin to be efficacious in preventing the growth and progression of UVB-induced BCC.
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Carcinoma Basocelular , Neoplasias Cutáneas , Animales , Carcinoma Basocelular/tratamiento farmacológico , Carcinoma Basocelular/metabolismo , Carcinoma Basocelular/prevención & control , Femenino , Proteínas Hedgehog/genética , Proteínas Hedgehog/metabolismo , Masculino , Ratones , Receptor Patched-1/genética , Silibina/farmacología , Silibina/uso terapéutico , Neoplasias Cutáneas/tratamiento farmacológico , Neoplasias Cutáneas/metabolismo , Neoplasias Cutáneas/prevención & control , Rayos Ultravioleta/efectos adversosRESUMEN
ATP-binding cassette, subfamily B member 11 (ABCB11) is an efflux transporter for bile acids on the liver canalicular membrane. The expression of this transporter is reduced in cholestasis; however, the mechanisms contributing to this reduction are unclear. In this study, we sought to determine whether miR-199a-5p contributes to the depletion of ABCB11/Abcb11 in cholestasis in mice. In a microRNA (miRNA) screen of mouse liver after common bile duct ligation (CBDL), we found that miR-199a-5p was significantly upregulated by approximately fourfold. In silico analysis predicted that miR-199a-5p would target the 3'-untranslated region (3'-UTR) of ABCB11/Abcb11 mRNA. The expression of ABCB11-3'-UTR luciferase construct in Huh-7 cells was markedly inhibited by cotransfection of a miRNA-199a-5p mimic, which was reversed by an miRNA-199a-5p mimic inhibitor. We also show treatment of mice after CBDL with the potent nuclear receptor FXR agonist obeticholic acid (OCA) significantly increased Abcb11 mRNA and protein and decreased miR-199a-5p expression. Computational mapping revealed a well-conserved FXR-binding site (FXRE) in the promoter of the gene encoding miR-199a-5, termed miR199a-2. Electromobility shift, chromatin immunoprecipitation, and miR199a-2 promoter-luciferase assays confirmed that this binding site was functional. Finally, CBDL in mice led to depletion of nuclear repressor NcoR1 binding at the miR199a-2 promoter, which facilitates transcription of miR199a-2. In CBDL mice treated with OCA, NcoR1 recruitment to the miR199a-2 FXRE was maintained at levels found in sham-operated mice. In conclusion, we demonstrate that miR-199a-5p is involved in regulating ABCB11/Abcb11 expression, is aberrantly upregulated in obstructive cholestasis, and is downregulated by the FXR agonist OCA.
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Miembro 11 de la Subfamilia B de Transportador de Casetes de Unión al ATP/biosíntesis , Colestasis/metabolismo , Regulación de la Expresión Génica , MicroARNs/metabolismo , Miembro 11 de la Subfamilia B de Transportador de Casetes de Unión al ATP/genética , Animales , Ácido Quenodesoxicólico/análogos & derivados , Ácido Quenodesoxicólico/farmacología , Colestasis/tratamiento farmacológico , Colestasis/genética , Colestasis/patología , Modelos Animales de Enfermedad , Masculino , Ratones , Ratones Noqueados , MicroARNs/genética , Co-Represor 1 de Receptor Nuclear/genética , Co-Represor 1 de Receptor Nuclear/metabolismoRESUMEN
Silica nanoparticles (SiNPs) released during the burning of sugarcane have been postulated to have a role in chronic kidney disease of unknown etiology. We tested the hypothesis that pristine SiNPs of the size present in sugarcane might cause chronic kidney injury when administered through the lung in rats. We administered 200- or 300-nm amorphous SiNPs twice weekly (4 mg/dose), or vehicle by oropharyngeal aspiration for 13 wk to rats followed by euthanasia after an additional 13 wk (26 wk total). Tissues were evaluated for the presence of SiNPs and evidence of histological injury. Both sizes of SiNPs caused kidney damage, with early tubular injury and inflammation (at week 13) that continued to inflammation and chronic fibrosis at week 26 despite discontinuation of the SiNP administration. Both sizes of SiNPs caused local inflammation in the lung and kidney and were detected in the serum and urine at week 13, and the 200-nm particles were also localized to the kidney with no evidence of retention of the 300-nm particles. At week 26, there was some clearance of the 200-nm silica from the kidneys, and urinary levels of SiNPs were reduced but still significant in both 200- and 300 nm-exposed rats. In conclusion, inhaled SiNPs cause chronic kidney injury that progresses despite stopping the SiNP administration. These findings support the hypothesis that human exposure to amorphous silica nanoparticles found in burned sugarcane fields could have a participatory role in chronic kidney disease of unknown etiology.NEW & NOTEWORTHY Inhalation of silica nanoparticles (SiNPs) released during the burning of sugarcane has been postulated to have a role in chronic kidney disease of unknown etiology (CKDu). We administered 200- and 300-nm amorphous SiNPs to rats by aspiration and observed kidney damage with tubular injury and inflammation that persisted even after stopping the SiNP exposure. These findings support the hypothesis that human exposure to SiNPs found in sugarcane ash could have a participatory role CKDu.
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Nanopartículas , Insuficiencia Renal Crónica , Animales , Inflamación/patología , Pulmón/patología , Nanopartículas/toxicidad , Ratas , Insuficiencia Renal Crónica/inducido químicamente , Insuficiencia Renal Crónica/patología , Dióxido de Silicio/toxicidadRESUMEN
BACKGROUND AND AIMS: Chronically administered parenteral nutrition (PN) in patients with intestinal failure carries the risk for developing PN-associated cholestasis (PNAC). We have demonstrated that farnesoid X receptor (FXR) and liver X receptor (LXR), proinflammatory interleukin-1 beta (IL-1ß), and infused phytosterols are important in murine PNAC pathogenesis. In this study we examined the role of nuclear receptor liver receptor homolog 1 (LRH-1) and phytosterols in PNAC. APPROACH AND RESULTS: In a C57BL/6 PNAC mouse model (dextran sulfate sodium [DSS] pretreatment followed by 14 days of PN; DSS-PN), hepatic nuclear receptor subfamily 5, group A, member 2/LRH-1 mRNA, LRH-1 protein expression, and binding of LRH-1 at the Abcg5/8 and Cyp7a1 promoter was reduced. Interleukin-1 receptor-deficient mice (Il-1r-/- /DSS-PN) were protected from PNAC and had significantly increased hepatic mRNA and protein expression of LRH-1. NF-κB activation and binding to the LRH-1 promoter were increased in DSS-PN PNAC mice and normalized in Il-1r-/- /DSS-PN mice. Knockdown of NF-κB in IL-1ß-exposed HepG2 cells increased expression of LRH-1 and ABCG5. Treatment of HepG2 cells and primary mouse hepatocytes with an LRH-1 inverse agonist, ML179, significantly reduced mRNA expression of FXR targets ATP binding cassette subfamily C member 2/multidrug resistance associated protein 2 (ABCC2/MRP2), nuclear receptor subfamily 0, groupB, member 2/small heterodimer partner (NR0B2/SHP), and ATP binding cassette subfamily B member 11/bile salt export pump (ABCB11/BSEP). Co-incubation with phytosterols further reduced expression of these genes. Similar results were obtained by suppressing the LRH-1 targets ABCG5/8 by treatment with small interfering RNA, IL-1ß, or LXR antagonist GSK2033. Liquid chromatography-mass spectrometry and chromatin immunoprecipitation experiments in HepG2 cells showed that ATP binding cassette subfamily G member 5/8 (ABCG5/8) suppression by GSK2033 increased the accumulation of phytosterols and reduced binding of FXR to the SHP promoter. Finally, treatment with LRH-1 agonist, dilauroyl phosphatidylcholine (DLPC) protected DSS-PN mice from PNAC. CONCLUSIONS: This study suggests that NF-κB regulation of LRH-1 and downstream genes may affect phytosterol-mediated antagonism of FXR signaling in the pathogenesis of PNAC. LRH-1 could be a potential therapeutic target for PNAC.
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Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 5/metabolismo , Transportador de Casete de Unión a ATP, Subfamilia G, Miembro 8/metabolismo , Colestasis/etiología , Lipoproteínas/metabolismo , FN-kappa B/metabolismo , Nutrición Parenteral/efectos adversos , Fitosteroles/metabolismo , Receptores Citoplasmáticos y Nucleares/metabolismo , Animales , Colestasis/metabolismo , Inmunoprecipitación de Cromatina , Modelos Animales de Enfermedad , Cromatografía de Gases y Espectrometría de Masas , Técnicas de Silenciamiento del Gen , Células Hep G2 , Humanos , Ratones , Ratones Endogámicos C57BLRESUMEN
Nitric oxide (NO) is a major inhibitory neurotransmitter that mediates nonadrenergic noncholinergic (NANC) signaling. Neuronal NO synthase (nNOS) is activated by Ca2+/calmodulin to produce NO, which causes smooth muscle relaxation to regulate physiologic tone. nNOS serine1412 (S1412) phosphorylation may reduce the activating Ca2+ requirement and sustain NO production. We developed and characterized a nonphosphorylatable nNOSS1412A knock-in mouse and evaluated its enteric neurotransmission and gastrointestinal (GI) motility to understand the physiologic significance of nNOS S1412 phosphorylation. Electrical field stimulation (EFS) of wild-type (WT) mouse ileum induced nNOS S1412 phosphorylation that was blocked by tetrodotoxin and by inhibitors of the protein kinase Akt but not by PKA inhibitors. Low-frequency depolarization increased nNOS S1412 phosphorylation and relaxed WT ileum but only partially relaxed nNOSS1412A ileum. At higher frequencies, nNOS S1412 had no effect. nNOSS1412A ileum expressed less phosphodiesterase-5 and was more sensitive to relaxation by exogenous NO. Under non-NANC conditions, peristalsis and segmentation were faster in the nNOSS1412A ileum. Together these findings show that neuronal depolarization stimulates enteric nNOS phosphorylation by Akt to promote normal GI motility. Thus, phosphorylation of nNOS S1412 is a significant regulatory mechanism for nitrergic neurotransmission in the gut.
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Motilidad Gastrointestinal , Íleon/fisiología , Neuronas/metabolismo , Óxido Nítrico Sintasa de Tipo I/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Alanina/metabolismo , Animales , GMP Cíclico/metabolismo , Motilidad Gastrointestinal/genética , Ratones , Músculo Liso/metabolismo , Mutación , Óxido Nítrico/metabolismo , Óxido Nítrico Sintasa de Tipo I/genética , Fosforilación , RatasRESUMEN
Thioredoxin reductase-1 (TrxR1)-, glutathione reductase (Gsr)-, and Nrf2 transcription factor-driven antioxidant systems form an integrated network that combats potentially carcinogenic oxidative damage yet also protects cancer cells from oxidative death. Here we show that although unchallenged wild-type (WT), TrxR1-null, or Gsr-null mouse livers exhibited similarly low DNA damage indices, these were 100-fold higher in unchallenged TrxR1/Gsr-double-null livers. Notwithstanding, spontaneous cancer rates remained surprisingly low in TrxR1/Gsr-null livers. All genotypes, including TrxR1/Gsr-null, were susceptible to N-diethylnitrosamine (DEN)-induced liver cancer, indicating that loss of these antioxidant systems did not prevent cancer cell survival. Interestingly, however, following DEN treatment, TrxR1-null livers developed threefold fewer tumors compared with WT livers. Disruption of TrxR1 in a marked subset of DEN-initiated cancer cells had no effect on their subsequent contributions to tumors, suggesting that TrxR1-disruption does not affect cancer progression under normal care, but does decrease the frequency of DEN-induced cancer initiation. Consistent with this idea, TrxR1-null livers showed altered basal and DEN-exposed metabolomic profiles compared with WT livers. To examine how oxidative stress influenced cancer progression, we compared DEN-induced cancer malignancy under chronically low oxidative stress (TrxR1-null, standard care) vs. elevated oxidative stress (TrxR1/Gsr-null livers, standard care or phenobarbital-exposed TrxR1-null livers). In both cases, elevated oxidative stress was correlated with significantly increased malignancy. Finally, although TrxR1-null and TrxR1/Gsr-null livers showed strong Nrf2 activity in noncancerous hepatocytes, there was no correlation between malignancy and Nrf2 expression within tumors across genotypes. We conclude that TrxR1, Gsr, Nrf2, and oxidative stress are major determinants of liver cancer but in a complex, context-dependent manner.
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Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patología , Glutatión Reductasa/metabolismo , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patología , Estrés Oxidativo/fisiología , Tiorredoxina Reductasa 1/metabolismo , Animales , Antioxidantes/metabolismo , Daño del ADN/fisiología , Progresión de la Enfermedad , Regulación de la Expresión Génica/fisiología , Glutatión/metabolismo , Hepatocitos/metabolismo , Hígado/metabolismo , Hígado/patología , Masculino , Metaboloma/fisiología , Ratones , Factor 2 Relacionado con NF-E2/metabolismo , Oxidación-ReducciónRESUMEN
Nonalcoholic fatty liver disease is a rapidly rising problem in the 21st century and is a leading cause of chronic liver disease that can lead to end-stage liver diseases, including cirrhosis and hepatocellular cancer. Despite this rising epidemic, no pharmacological treatment has yet been established to treat this disease. The rapidly increasing prevalence of nonalcoholic fatty liver disease and its aggressive form, nonalcoholic steatohepatitis (NASH), requires novel therapeutic approaches to prevent disease progression. Alterations in microbiome dynamics and dysbiosis play an important role in liver disease and may represent targetable pathways to treat liver disorders. Improving microbiome properties or restoring normal bile acid metabolism may prevent or slow the progression of liver diseases such as NASH. Importantly, aberrant systemic circulation of bile acids can greatly disrupt metabolic homeostasis. Bile acid sequestrants are orally administered polymers that bind bile acids in the intestine, forming nonabsorbable complexes. Bile acid sequestrants interrupt intestinal reabsorption of bile acids, decreasing their circulating levels. We determined that treatment with the bile acid sequestrant sevelamer reversed the liver injury and prevented the progression of NASH, including steatosis, inflammation, and fibrosis in a Western diet-induced NASH mouse model. Metabolomics and microbiome analysis revealed that this beneficial effect is associated with changes in the microbiota population and bile acid composition, including reversing microbiota complexity in cecum by increasing Lactobacillus and decreased Desulfovibrio The net effect of these changes was improvement in liver function and markers of liver injury and the positive effects of reversal of insulin resistance.
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Ácidos y Sales Biliares/metabolismo , Dieta Occidental , Hígado/efectos de los fármacos , Enfermedad del Hígado Graso no Alcohólico/patología , Sevelamer/farmacología , Animales , Ácidos y Sales Biliares/química , Ciego/microbiología , Quimiocina CCL2/genética , Quimiocina CCL2/metabolismo , Colesterol/análisis , Colágeno Tipo I/genética , Colágeno Tipo I/metabolismo , Cadena alfa 1 del Colágeno Tipo I , Modelos Animales de Enfermedad , Heces/química , Microbioma Gastrointestinal/efectos de los fármacos , Lactobacillus/efectos de los fármacos , Metabolismo de los Lípidos/efectos de los fármacos , Hígado/metabolismo , Hígado/patología , Masculino , Ratones , Ratones Endogámicos C57BL , Enfermedad del Hígado Graso no Alcohólico/metabolismo , Enfermedad del Hígado Graso no Alcohólico/prevención & control , Sevelamer/química , Sevelamer/uso terapéutico , Índice de Severidad de la Enfermedad , Factor de Crecimiento Transformador beta/genética , Factor de Crecimiento Transformador beta/metabolismoRESUMEN
Acetaminophen (n-acetyl-p-aminophenol, APAP) use in the neonatal intensive care unit is rapidly increasing. Although APAP-related hepatotoxicity is rarely reported in the neonatal literature, other end-organ toxicity can occur with toxic exposures. APAP-induced lung injury has been reported with toxic exposures in adults, but whether this occurs in the developing lung is unknown. Therefore, we tested whether toxic APAP exposures would injure the developing lung. Neonatal C57BL/6 mice (PN7, early alveolar stage of lung development) were exposed to a dose of APAP known to cause hepatotoxicity in adult mice (280 mg/kg, IP). This exposure induced significant lung injury in the absence of identifiable hepatic toxicity. This injury was associated with increased pulmonary expression of Cyp2e1, the xenobiotic enzyme responsible for the toxic conversion of APAP. Exposure was associated with increased pulmonary expression of antioxidant response genes and decreased pulmonary glutathione peroxidase activity level. Furthermore, we observed an increase in pulmonary expression of proinflammatory cytokines and chemokines. Lastly, we were able to demonstrate that this toxic APAP exposure was associated with a shift in pulmonary metabolism away from glycolysis with increased oxidative phosphorylation, a finding consistent with increased mitochondrial workload, potentially leading to mitochondrial toxicity. This previously unrecognized injury and metabolic implications highlight the need to look beyond the liver and evaluate both the acute and long-term pulmonary implications of APAP exposure in the perinatal period.
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Acetaminofén/efectos adversos , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Lesión Pulmonar/metabolismo , Pulmón/crecimiento & desarrollo , Acetaminofén/farmacología , Animales , Citocromo P-450 CYP2E1/biosíntesis , Glucólisis/efectos de los fármacos , Lesión Pulmonar/inducido químicamente , Lesión Pulmonar/patología , Masculino , Ratones , Fosforilación Oxidativa/efectos de los fármacosRESUMEN
Both preclinical and clinical studies have demonstrated that exposures to acetaminophen (APAP) at levels that cause hepatic injury cause pulmonary injury as well. However, whether exposures that do not result in hepatic injury have acute pulmonary implications is unknown. Thus, we sought to determine how APAP exposures at levels that do not result in significant hepatic injury impact the mature lung. Adult male ICR mice (8-12 wk) were exposed to a dose of APAP known to cause hepatotoxicity in adult mice [280 mg/kg, intraperitoneal (ip)], as well as a lower dose previously reported to not cause hepatic injury (140 mg/kg, ip). We confirm that the lower dose exposures did not result in significant hepatic injury. However, like high dose, lower exposure resulted in increased cellular content of the bronchoalveolar lavage fluid and induced a proinflammatory pulmonary transcriptome. Both the lower and higher dose exposures resulted in measurable changes in lung morphometrics, with the lower dose exposure causing alveolar wall thinning. Using RNAScope, we were able to detect dose-dependent, APAP-induced pulmonary Cyp2e1 expression. Finally, using FLIM we determined that both APAP exposures resulted in acute pulmonary metabolic changes consistent with mitochondrial overload in lower doses and a shift to glycolysis at a high dose. Our findings demonstrate that APAP exposures that do not cause significant hepatic injury result in acute inflammatory, morphometric, and metabolic changes in the mature lung. These previously unreported findings may help explain the potential relationship between APAP exposures and pulmonary-related morbidity.
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Acetaminofén/toxicidad , Hígado/efectos de los fármacos , Lesión Pulmonar/tratamiento farmacológico , Pulmón/efectos de los fármacos , Acetaminofén/metabolismo , Animales , Citocromo P-450 CYP2E1/metabolismo , Modelos Animales de Enfermedad , Glucólisis/efectos de los fármacos , Hígado/metabolismo , Pulmón/metabolismo , Lesión Pulmonar/metabolismo , Ratones , Ratones Endogámicos ICRRESUMEN
BACKGROUND: Pelvic organ prolapse is common, but the underlying etiologies are poorly understood, which limits our current prevention and treatment options. OBJECTIVE: Our primary objective was to compare the uterosacral ligament histologic features in women with and without prolapse using the novel pelvic organ prolapse histologic quantification system. Our secondary aim was to determine whether composite histologic findings in uterosacral ligaments are associated with prolapse risk factors. STUDY DESIGN: This was a prospective cohort study in which paracervical uterosacral ligament biopsies were performed at the time of hysterectomy for primary prolapse or other benign gynecologic indications and processed for histologic evaluation. The pelvic organ prolapse quantification system was used to determine the prolapse stage. In this study, 9 prominent histologic features were semiquantitatively scored using the pelvic organ prolapse histologic quantification system in a blinded fashion and compared between prolapse and control groups. Unbiased principal component analysis of these scores was independently performed to identify potential relationships between histologic measures and prolapse risk factors. RESULTS: The histologic scores of 81 prolapse and 33 control ligaments were analyzed. Compared with the control group, women in the prolapse group were significantly older and more likely to be in the menopausal phase. There was no difference in the number of vaginal deliveries, body mass index, hormone use, or smoking status between the groups. To control for baseline differences, patients were also stratified by age over 40 years and menopausal status. Compared with the control group, the prolapse ligaments in the premenopausal group had significantly more loss of smooth muscle fibers within the fascicles (P<.001), increased inflammatory infiltrates of neutrophils within the tissue and perineural inflammatory cells (P<.01 and P=.04, respectively), and reduced neointimal hyperplasia (P=.02). Prolapse ligaments in the postmenopausal group exhibited elevated adipose content compared with that of the control group (P=.05). Amount of fibrillar collagen, total nonvascular smooth muscle, and muscle fiber vesicles of prolapse ligaments did not differ in either the premenopausal or postmenopausal group compared with that of the control group. Unbiased principal component analysis of the histologic scores separated the prolapse ligaments into 3 phenotypes: (1) increased adipose accumulation, (2) increased inflammation, and (3) abnormal vasculature, with variable overlap with controls. Posthoc analysis of these subgroups demonstrated a positive correlation between increasing number of vaginal deliveries and body mass index with increasing adipose content in the adipocyte accumulation and inflammatory phenotype and increasing neointimal hyperplasia in the vascular phenotype. However, only the relationship between vaginal delivery and adipocytes was significant in the adipose phenotype (R2=0.13; P=.04). CONCLUSION: Histologic phenotypes exist in pelvic support ligaments that can be distinguished using the pelvic organ prolapse histologic quantification system and principle component analysis. Vaginal delivery is associated with aberrant adipose accumulation in uterosacral ligaments. Our findings support a multifactorial etiology for pelvic organ prolapse contributing to altered smooth muscle, vasculature, and connective tissue content in crucial pelvic support structures. To confirm these associations and evaluate the biomechanical properties of histologic phenotypes of prolapse, larger studies are warranted. Closing this gap in knowledge will help optimize personalized medicine and help identify targets for prevention and treatment of this complex condition.