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1.
BMC Med Educ ; 24(1): 639, 2024 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-38849838

RESUMEN

BACKGROUND: This study aimed to (1) evaluate the current status of obesity education at Case Western Reserve University School of Medicine (CWRU) (2), introduce a comprehensive first-year curriculum on obesity, and (3) assess the impact of the curriculum on self-reported attitudes and knowledge regarding obesity among first-year medical students. METHODS: The preclinical curriculum at CWRU was reviewed to determine the degree of coverage of Obesity Medicine Education Collaborative (OMEC) competencies for healthcare professionals, and recommendations were provided for revising the curriculum to better adhere to these evidence-based competencies. A survey on obesity attitudes and knowledge was given before and after the implementation of the new curriculum to measure intervention-related changes. Changes in obesity attitudes and knowledge were compared (1) before and after the intervention for the class of 2025 and (2) after the intervention for the class of 2025 to a historical cohort that did not receive the intervention. RESULTS: Among the 27 competencies examined in the audit, 55% were unmet and 41% were partially met. Of 186 first-year medical students (M1s), 29 (16%) completed the baseline survey and 26 (14%) completed the post-intervention survey. Following the intervention, there was a notable improvement in attitudes and knowledge regarding obesity. Specifically, there was a significant decrease in the belief that obesity is caused by poor personal choices, and knowledge of obesity in fourteen out of fifteen areas showed significant improvement from pre- to post-intervention. Additionally, obesity attitudes and knowledge were significantly better post-intervention when compared to the historical cohort. CONCLUSIONS: The improvements made to the preclinical curriculum through this project improved obesity attitudes and knowledge among first-year medical students. This method provides a practical approach for evaluating and enhancing obesity education in medical school curricula.


Asunto(s)
Curriculum , Educación de Pregrado en Medicina , Obesidad , Humanos , Obesidad/terapia , Educación de Pregrado en Medicina/normas , Competencia Clínica , Estudiantes de Medicina , Conocimientos, Actitudes y Práctica en Salud , Masculino , Femenino , Evaluación de Programas y Proyectos de Salud , Actitud del Personal de Salud
2.
Teach Learn Med ; 33(3): 334-342, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33706632

RESUMEN

Issue: Calls to change medical education have been frequent, persistent, and generally limited to alterations in content or structural re-organization. Self-imposed barriers have prevented adoption of more radical pedagogical approaches, so recent predictions of the 'inevitability' of medical education transitioning to online delivery seemed unlikely. Then in March 2020 the COVID-19 pandemic forced medical schools to overcome established barriers overnight and make the most rapid curricular shift in medical education's history. We share the collated reports of nine medical schools and postulate how recent responses may influence future medical education. Evidence: While extraneous pandemic-related factors make it impossible to scientifically distinguish the impact of the curricular changes, some themes emerged. The rapid transition to online delivery was made possible by all schools having learning management systems and key electronic resources already blended into their curricula; we were closer to online delivery than anticipated. Student engagement with online delivery varied with different pedagogies used and the importance of social learning and interaction along with autonomy in learning were apparent. These are factors known to enhance online learning, and the student-centered modalities (e.g. problem-based learning) that included them appeared to be more engaging. Assumptions that the new online environment would be easily adopted and embraced by 'technophilic' students did not always hold true. Achieving true distance medical education will take longer than this 'overnight' response, but adhering to best practices for online education may open a new realm of possibilities. Implications: While this experience did not confirm that online medical education is really 'inevitable,' it revealed that it is possible. Thoughtfully blending more online components into a medical curriculum will allow us to take advantage of this environment's strengths such as efficiency and the ability to support asynchronous and autonomous learning that engage and foster intrinsic learning in our students. While maintaining aspects of social interaction, online learning could enhance pre-clinical medical education by allowing integration and collaboration among classes of medical students, other health professionals, and even between medical schools. What remains to be seen is whether COVID-19 provided the experience, vision and courage for medical education to change, or whether the old barriers will rise again when the pandemic is over.


Asunto(s)
COVID-19 , Educación a Distancia , Educación de Pregrado en Medicina/organización & administración , Facultades de Medicina , Humanos , SARS-CoV-2 , Estudiantes de Medicina
3.
J Biol Chem ; 293(9): 3399-3409, 2018 03 02.
Artículo en Inglés | MEDLINE | ID: mdl-29317502

RESUMEN

Phosphoenolpyruvate carboxykinase (Pck1) is a metabolic enzyme that is integral to the gluconeogenic and glyceroneogenic pathways. However, Pck1's role in macrophage metabolism and function is unknown. Using stable isotopomer MS analysis in a mouse model with a myeloid cell-specific Pck1 deletion, we show here that this deletion increases the proinflammatory phenotype in macrophages. Incubation of LPS-stimulated bone marrow-derived macrophages (BMDM) with [U-13C]glucose revealed reduced 13C labeling of citrate and malate and increased 13C labeling of lactate in Pck1-deleted bone marrow-derived macrophages. We also found that the Pck1 deletion in the myeloid cells increases reactive oxygen species (ROS). Of note, this altered macrophage metabolism increased expression of the M1 cytokines TNFα, IL-1ß, and IL-6. We therefore conclude that Pck1 contributes to M1 polarization in macrophages. Our findings provide important insights into the factors determining the macrophage inflammatory response and indicate that Pck1 activity contributes to metabolic reprogramming and polarization in macrophages.


Asunto(s)
Eliminación de Gen , Macrófagos/enzimología , Fenotipo , Fosfoenolpiruvato Carboxiquinasa (GTP)/deficiencia , Fosfoenolpiruvato Carboxiquinasa (GTP)/genética , Animales , Polaridad Celular , Glucosa/metabolismo , Glutamina/metabolismo , Inflamación/enzimología , Inflamación/genética , Inflamación/inmunología , Macrófagos/citología , Macrófagos/metabolismo , Ratones , Ácido Palmítico/metabolismo , Células RAW 264.7
4.
Proc Natl Acad Sci U S A ; 112(31): 9680-5, 2015 Aug 04.
Artículo en Inglés | MEDLINE | ID: mdl-26195767

RESUMEN

Several components of the canonical pathway of response to lipopolysaccharide (LPS) are required for the EGF-dependent activation of NFκB. Conversely, the ability of Toll-like Receptor 4 (TLR4) to activate NFκB in response to LPS is impaired by down regulating EGF receptor (EGFR) expression or by using the EGFR inhibitor erlotinib. The LYN proto-oncogene (LYN) is required for signaling in both directions. LYN binds to the EGFR upon LPS stimulation, and erlotinib impairs this association. In mice, erlotinib blocks the LPS-induced expression of tumor necrosis factor α (TNFα) and interleukin-6 (IL-6) and ameliorates LPS-induced endotoxity, revealing that EGFR is essential for LPS-induced signaling in vivo.


Asunto(s)
Receptores ErbB/metabolismo , Lipopolisacáridos/toxicidad , Sustancias Protectoras/farmacología , Quinazolinas/farmacología , Transducción de Señal/efectos de los fármacos , Receptor Toll-Like 4/metabolismo , Animales , Línea Celular , Citocinas/metabolismo , Factor de Crecimiento Epidérmico/farmacología , Clorhidrato de Erlotinib , Silenciador del Gen/efectos de los fármacos , Humanos , Quinasas Quinasa Quinasa PAM/metabolismo , Ratones , Factor 88 de Diferenciación Mieloide/metabolismo , FN-kappa B/metabolismo , Fosforilación/efectos de los fármacos , Proto-Oncogenes Mas , Factor de Necrosis Tumoral alfa/farmacología , Familia-src Quinasas/metabolismo
5.
Hepatology ; 64(5): 1518-1533, 2016 11.
Artículo en Inglés | MEDLINE | ID: mdl-27301788

RESUMEN

Multiple pathways of programmed cell death are important in liver homeostasis. Hepatocyte death is associated with progression of nonalcoholic fatty liver disease, and inhibition of apoptosis partially protects against liver injury in response to a high-fat diet (HFD). However, the contribution of necroptosis, a caspase-independent pathway of cell death, to HFD-induced liver injury is not known. Wild-type C57BL/6 and receptor interacting protein (RIP) 3-/- mice were randomized to chow or HFD. HFD-fed C57BL/6 mice increased expression of RIP3, the master regulator of necroptosis, as well as phosphorylated mixed lineage kinase domain-like, an effector of necroptotic cell death, in liver. HFD did not increase phosphorylated mixed lineage kinase domain-like in RIP3-/- mice. HFD increased fasting insulin and glucose, as well as glucose intolerance, in C57BL/6 mice. RIP3-/- mice were glucose-intolerant even on the chow diet; HFD further increased fasting glucose and insulin but not glucose intolerance. HFD also increased hepatic steatosis, plasma alanine aminotransferase activity, inflammation, oxidative stress, and hepatocellular apoptosis in wild-type mice; these responses were exacerbated in RIP3-/- mice. Importantly, increased inflammation and injury were associated with early indicators of fibrosis in RIP3-/- compared to C57BL/6 mice. Culture of AML12 hepatocytes with palmitic acid increased cytotoxicity through apoptosis and necrosis. Inhibition of RIP1 with necrostatin-1 or small interfering RNA knockdown of RIP3 reduced palmitic acid-induced cytotoxicity. CONCLUSION: Absence of RIP3, a key mediator of necroptosis, exacerbated HFD-induced liver injury, associated with increased inflammation and hepatocyte apoptosis, as well as early fibrotic responses; these findings indicate that shifts in the mode of hepatocellular death can influence disease progression and have therapeutic implications because manipulation of hepatocyte cell death pathways is being considered as a target for treatment of nonalcoholic fatty liver disease. (Hepatology 2016;64:1518-1533).


Asunto(s)
Dieta Alta en Grasa , Enfermedad del Hígado Graso no Alcohólico/etiología , Proteína Serina-Treonina Quinasas de Interacción con Receptores/fisiología , Animales , Apoptosis , Muerte Celular , Hepatocitos , Masculino , Ratones , Ratones Endogámicos C57BL , Enfermedad del Hígado Graso no Alcohólico/prevención & control , Distribución Aleatoria
6.
J Biol Chem ; 290(29): 18227-18236, 2015 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-26070567

RESUMEN

Astrocyte elevated gene-1 (AEG-1), also known as MTDH (metadherin) or LYRIC, is an established oncogene. However, the physiological function of AEG-1 is not known. To address this question, we generated an AEG-1 knock-out mouse (AEG-1KO) and characterized it. Although AEG-1KO mice were viable and fertile, they were significantly leaner with prominently less body fat and lived significantly longer compared with wild type (WT). When fed a high fat and cholesterol diet (HFD), WT mice rapidly gained weight, whereas AEG-1KO mice did not gain weight at all. This phenotype of AEG-1KO mice is due to decreased fat absorption from the intestines, not because of decreased fat synthesis or increased fat consumption. AEG-1 interacts with retinoid X receptor (RXR) and inhibits RXR function. In enterocytes of AEG-1KO mice, we observed increased activity of RXR heterodimer partners, liver X receptor and peroxisome proliferator-activated receptor-α, key inhibitors of intestinal fat absorption. Inhibition of fat absorption in AEG-1KO mice was further augmented when fed an HFD providing ligands to liver X receptor and peroxisome proliferator-activated receptor-α. Our studies reveal a novel role of AEG-1 in regulating nuclear receptors controlling lipid metabolism. AEG-1 may significantly modulate the effects of HFD and thereby function as a unique determinant of obesity.


Asunto(s)
Mucosa Intestinal/metabolismo , Metabolismo de los Lípidos , Hígado/metabolismo , Proteínas de la Membrana/metabolismo , Aumento de Peso , Tejido Adiposo/metabolismo , Animales , Homeostasis , Receptores X del Hígado , Masculino , Proteínas de la Membrana/genética , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Obesidad/genética , Obesidad/metabolismo , Receptores Nucleares Huérfanos/metabolismo , Receptores Activados del Proliferador del Peroxisoma/metabolismo , Proteínas de Unión al ARN , Receptores X Retinoide/metabolismo
7.
Am J Physiol Endocrinol Metab ; 311(5): E869-E880, 2016 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-27624101

RESUMEN

The peroxisome proliferator-activated receptor (PPAR) family of nuclear receptors is central to the pathophysiology and treatment of metabolic disease through the receptors' ability to regulate the expression of genes involved in glucose homeostasis, adipogenesis, and lipid metabolism. However, the mechanism by which PPAR is regulated remains incompletely understood. We generated a transgenic mouse strain (ZFP-TG) that overexpressed Zfp407 primarily in muscle and heart. Transcriptome analysis by RNA-Seq identified 1,300 differentially expressed genes in the muscle of ZFP-TG mice, among which PPAR target genes were significantly enriched. Among the physiologically important PPARγ target genes, Glucose transporter (Glut)-4 mRNA and protein levels were increased in heart and muscle. The increase in Glut4 and other transcriptional effects of Zfp407 overexpression together decreased body weight and lowered plasma glucose, insulin, and HOMA-IR scores relative to control littermates. When placed on high-fat diet, ZFP-TG mice remained more glucose tolerant than their wild-type counterparts. Cell-based assays demonstrated that Zfp407 synergistically increased the transcriptional activity of all PPAR subtypes, PPARα, PPARγ, and PPARδ. The increased PPAR activity was not associated with increased PPAR mRNA or protein levels, suggesting that Zfp407 posttranslationally regulates PPAR activity. Collectively, these results demonstrate that Zfp407 overexpression improved glucose homeostasis. Thus, Zfp407 represents a new drug target for treating metabolic disease.


Asunto(s)
Glucemia/metabolismo , Proteínas de Unión al ADN/genética , Transportador de Glucosa de Tipo 4/metabolismo , Receptores Activados del Proliferador del Peroxisoma/genética , Animales , Dieta Alta en Grasa , Perfilación de la Expresión Génica , Glucosa/metabolismo , Transportador de Glucosa de Tipo 4/genética , Homeostasis/genética , Insulina/metabolismo , Resistencia a la Insulina/genética , Masculino , Ratones , Ratones Transgénicos , Músculo Esquelético/metabolismo , Miocardio/metabolismo , PPAR alfa/genética , PPAR alfa/metabolismo , PPAR delta/genética , PPAR delta/metabolismo , PPAR gamma/genética , PPAR gamma/metabolismo , Receptores Activados del Proliferador del Peroxisoma/metabolismo , Procesamiento Proteico-Postraduccional/genética , ARN Mensajero/metabolismo , Factores de Transcripción/genética
8.
NMR Biomed ; 29(1): 84-9, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-26608869

RESUMEN

Autosomal recessive polycystic kidney disease (ARPKD) is a potentially lethal multi-organ disease affecting both the kidneys and the liver. Unfortunately, there are currently no non-invasive methods to monitor liver disease progression in ARPKD patients, limiting the study of potential therapeutic interventions. Herein, we perform an initial investigation of T1 relaxation time as a potential imaging biomarker to quantitatively assess the two primary pathologic hallmarks of ARPKD liver disease: biliary dilatation and periportal fibrosis in the PCK rat model of ARPKD. T1 relaxation time results were obtained for five PCK rats at 3 months of age using a Look-Locker acquisition on a Bruker BioSpec 7.0 T MRI scanner. Six three-month-old Sprague-Dawley (SD) rats were also scanned as controls. All animals were euthanized after the three-month scans for histological and biochemical assessments of bile duct dilatation and hepatic fibrosis for comparison. PCK rats exhibited significantly increased liver T1 values (mean ± standard deviation = 935 ± 39 ms) compared with age-matched SD control rats (847 ± 26 ms, p = 0.01). One PCK rat exhibited severe cholangitis (mean T1 = 1413 ms), which occurs periodically in ARPKD patients. The observed increase in the in vivo liver T1 relaxation time correlated significantly with three histological and biochemical indicators of biliary dilatation and fibrosis: bile duct area percent (R = 0.85, p = 0.002), periportal fibrosis area percent (R = 0.82, p = 0.004), and hydroxyproline content (R = 0.76, p = 0.01). These results suggest that hepatic T1 relaxation time may provide a sensitive and non-invasive imaging biomarker to monitor ARPKD liver disease.


Asunto(s)
Hígado/patología , Imagen por Resonancia Magnética/métodos , Riñón Poliquístico Autosómico Recesivo/patología , Animales , Biomarcadores , Masculino , Ratas , Ratas Sprague-Dawley
9.
FASEB J ; 28(1): 26-34, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24036882

RESUMEN

Vitamin A, retinol, circulates in blood bound to retinol-binding protein (RBP). At some tissues, holo-RBP is recognized by a plasma membrane receptor termed STRA6, which serves a dual role: it mediates transport of retinol from RBP into cells, and it functions as a cytokine receptor that, on binding holo-RBP, activates JAK2/STAT5 signaling. As STAT target genes include SOCS3, an inhibitor of insulin receptor, holo-RBP suppresses insulin responses in STRA6-expressing cells. We have shown previously that the two functions of STRA6 are interdependent. These observations suggest factors that regulate STRA6-mediated retinol transport may also control STRA6-mediated cell signaling. One such factor is retinol metabolism, which enables cellular uptake of retinol by maintaining an inward-directed concentration gradient. We show here that lecithin:retinol acyl transferase (LRAT), which catalyzes esterification of retinol to its storage species retinyl esters, is necessary for activation of the STRA6/JAK2/STAT5 cascade by holo-RBP. In accordance, LRAT-null mice are protected from holo-RBP-induced suppression of insulin responses. Hence, STRA6 signaling, which requires STRA6-mediated retinol transport, is supported by LRAT-catalyzed retinol metabolism. The observations demonstrate that STRA6 regulates key cellular processes by coupling circulating holo-RBP levels and intracellular retinol metabolism to cell signaling.


Asunto(s)
Aciltransferasas/metabolismo , Proteínas de la Membrana/metabolismo , Proteínas de Unión al Retinol/metabolismo , Aciltransferasas/genética , Animales , Ingestión de Alimentos/fisiología , Prueba de Tolerancia a la Glucosa , Células Hep G2 , Humanos , Proteínas de la Membrana/genética , Ratones , Células 3T3 NIH , Reacción en Cadena en Tiempo Real de la Polimerasa , Proteínas de Unión al Retinol/genética , Proteína 3 Supresora de la Señalización de Citocinas , Proteínas Supresoras de la Señalización de Citocinas/genética , Proteínas Supresoras de la Señalización de Citocinas/metabolismo , Vitamina A/metabolismo
10.
Mediators Inflamm ; 2015: 909827, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26635450

RESUMEN

TThe molecular mechanisms responsible for the development of hepatic fibrosis are not fully understood. The Nlrc4 inflammasome detects cytosolic presence of bacterial components, activating inflammatory cytokines to facilitate clearance of pathogens and infected cells. We hypothesized that low-grade constitutive activation of the Nlrc4 inflammasome may lead to induced hepatocyte proliferation and prevent the development of hepatic fibrosis. The gene of Nlrc4 contains two single nucleotide polymorphisms (SNPs), one located within the Nlrc4 promoter and one contained within exon 5. These SNPs regulate Nlrc4 gene transcription and activation as measured through gene reporter assays and IL-1ß secretion. The 17C-6 mice have increased IL-1ß in plasma after chronic carbon tetrachloride (CCl4) administration compared to B6 mice. After two-thirds partial hepatectomy (2/3PH) 17C-6 mice have earlier restoration of liver mass with greater cyclin D1 protein and BrdU incorporation compared to B6 mice at several time points. These data reveal mild constitutive activation of the Nlrc4 inflammasome as the results of two SNPs, which leads to the stimulation of hepatocyte proliferation. The increased liver regeneration induces rapid liver mass recovery after hepatectomy and may prevent the development of hepatotoxin-induced liver fibrosis.


Asunto(s)
Proteínas Reguladoras de la Apoptosis/metabolismo , Proteínas de Unión al Calcio/metabolismo , Inflamasomas/metabolismo , Cirrosis Hepática/prevención & control , Regeneración Hepática/fisiología , Animales , Proteínas Reguladoras de la Apoptosis/genética , Proteínas Reguladoras de la Apoptosis/inmunología , Proteínas de Unión al Calcio/genética , Proteínas de Unión al Calcio/inmunología , Tetracloruro de Carbono/toxicidad , Hepatectomía , Proteínas de Homeodominio/metabolismo , Inflamasomas/inmunología , Interleucina-1beta/sangre , Cirrosis Hepática/inmunología , Cirrosis Hepática/metabolismo , Regeneración Hepática/genética , Regeneración Hepática/inmunología , Macrófagos/inmunología , Macrófagos/metabolismo , Masculino , Ratones , Ratones Congénicos , Ratones Endogámicos A , Ratones Endogámicos C57BL , Modelos Biológicos , Polimorfismo de Nucleótido Simple , Regiones Promotoras Genéticas , Células RAW 264.7
11.
J Biol Chem ; 288(34): 24528-39, 2013 Aug 23.
Artículo en Inglés | MEDLINE | ID: mdl-23839944

RESUMEN

The plasma membrane protein STRA6 is thought to mediate uptake of retinol from its blood carrier retinol-binding protein (RBP) into cells and to function as a surface receptor that, upon binding of holo-RBP, activates a JAK/STAT cascade. It was suggested that STRA6 signaling underlies insulin resistance induced by elevated serum levels of RBP in obese animals. To investigate these activities in vivo, we generated and analyzed Stra6-null mice. We show that the contribution of STRA6 to retinol uptake by tissues in vivo is small and that, with the exception of the eye, ablation of Stra6 has only a modest effect on retinoid homeostasis and does not impair physiological functions that critically depend on retinoic acid in the embryo or in the adult. However, ablation of Stra6 effectively protects mice from RBP-induced suppression of insulin signaling. Thus one biological function of STRA6 in tissues other than the eye appears to be the coupling of circulating holo-RBP levels to cell signaling, in turn regulating key processes such as insulin response.


Asunto(s)
Resistencia a la Insulina , Insulina/metabolismo , Proteínas de la Membrana/metabolismo , Obesidad/metabolismo , Proteínas Plasmáticas de Unión al Retinol/metabolismo , Vitamina A/metabolismo , Células 3T3-L1 , Animales , Ojo , Insulina/genética , Proteínas de la Membrana/genética , Ratones , Ratones Noqueados , Obesidad/genética , Obesidad/patología , Proteínas Plasmáticas de Unión al Retinol/genética , Transducción de Señal/genética
12.
J Biol Chem ; 288(24): 17202-13, 2013 Jun 14.
Artículo en Inglés | MEDLINE | ID: mdl-23645676

RESUMEN

Endoplasmic reticulum (ER) stress-induced responses are associated with the loss of insulin-producing ß-cells in type 2 diabetes mellitus. ß-Cell survival during ER stress is believed to depend on decreased protein synthesis rates that are mediated via phosphorylation of the translation initiation factor eIF2α. It is reported here that chronic ER stress correlated with increased islet protein synthesis and apoptosis in ß-cells in vivo. Paradoxically, chronic ER stress in ß-cells induced an anabolic transcription program to overcome translational repression by eIF2α phosphorylation. This program included expression of amino acid transporter and aminoacyl-tRNA synthetase genes downstream of the stress-induced ATF4-mediated transcription program. The anabolic response was associated with increased amino acid flux and charging of tRNAs for branched chain and aromatic amino acids (e.g. leucine and tryptophan), the levels of which are early serum indicators of diabetes. We conclude that regulation of amino acid transport in ß-cells during ER stress involves responses leading to increased protein synthesis, which can be protective during acute stress but can lead to apoptosis during chronic stress. These studies suggest that the increased expression of amino acid transporters in islets can serve as early diagnostic biomarkers for the development of diabetes.


Asunto(s)
Aminoácidos/metabolismo , Apoptosis , Diabetes Mellitus Tipo 2/metabolismo , Estrés del Retículo Endoplásmico , Células Secretoras de Insulina/fisiología , Factor de Transcripción Activador 4/metabolismo , Sistemas de Transporte de Aminoácidos/genética , Sistemas de Transporte de Aminoácidos/metabolismo , Aminoacil-ARNt Sintetasas/genética , Aminoacil-ARNt Sintetasas/metabolismo , Animales , Supervivencia Celular , Diabetes Mellitus Tipo 2/patología , Factor 2 Eucariótico de Iniciación/metabolismo , Células HEK293 , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Fosforilación , Biosíntesis de Proteínas , Procesamiento Proteico-Postraduccional , ARN de Transferencia/metabolismo , Activación Transcripcional
13.
Genome Res ; 21(7): 1065-73, 2011 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-21507882

RESUMEN

Although central to many studies of phenotypic variation and disease susceptibility, characterizing the genetic architecture of complex traits has been unexpectedly difficult. For example, most of the susceptibility genes that contribute to highly heritable conditions such as obesity and type 2 diabetes (T2D) remain to be identified despite intensive study. We took advantage of mouse models of diet-induced metabolic disease in chromosome substitution strains (CSSs) both to characterize the genetic architecture of diet-induced obesity and glucose homeostasis and to test the feasibility of gene discovery. Beginning with a survey of CSSs, followed with genetic and phenotypic analysis of congenic, subcongenic, and subsubcongenic strains, we identified a remarkable number of closely linked, phenotypically heterogeneous quantitative trait loci (QTLs) on mouse chromosome 6 that have unexpectedly large phenotypic effects. Although fine-mapping reduced the genomic intervals and gene content of these QTLs over 3000-fold, the average phenotypic effect on body weight was reduced less than threefold, highlighting the "fractal" nature of genetic architecture in mice. Despite this genetic complexity, we found evidence for 14 QTLs in only 32 recombination events in less than 3000 mice, and with an average of four genes located within the three body weight QTLs in the subsubcongenic strains. For Obrq2a1, genetic and functional studies collectively identified the solute receptor Slc35b4 as a regulator of obesity, insulin resistance, and gluconeogenesis. This work demonstrated the unique power of CSSs as a platform for studying complex genetic traits and identifying QTLs.


Asunto(s)
Glucosa/metabolismo , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Homeostasis/genética , Proteínas de Transporte de Nucleótidos/genética , Obesidad/genética , Sitios de Carácter Cuantitativo , Animales , Peso Corporal/genética , Mapeo Cromosómico , Cromosomas de los Mamíferos/genética , Diabetes Mellitus Tipo 2/genética , Dieta , Regulación de la Expresión Génica , Gluconeogénesis/genética , Células Hep G2 , Humanos , Resistencia a la Insulina/genética , Masculino , Ratones , Ratones Congénicos , Modelos Animales , Proteínas de Transporte de Nucleótidos/metabolismo , Fenotipo , Análisis de Secuencia de ADN
14.
Arch Biochem Biophys ; 548: 11-9, 2014 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-24631573

RESUMEN

We have reported that Mg(2+) dynamically regulates glucose 6-phosphate entry into the endoplasmic reticulum and its hydrolysis by the glucose 6-phosphatase in liver cells. In the present study, we report that by modulating glucose 6-phosphate entry into the endoplasmic reticulum of HepG2 cells, Mg(2+) also regulates the oxidation of this substrate via hexose 6-phosphate dehydrogenase (H6PD). This regulatory effect is dynamic as glucose 6-phosphate entry and oxidation can be rapidly down-regulated by the addition of exogenous Mg(2+). In addition, HepG2 cells growing in low Mg(2+) show a marked increase in hexose 6-phosphate dehydrogenase mRNA and protein expression. Metabolically, these effects on hexose 6-phosphate dehydrogenase are important as this enzyme increases intra-reticular NADPH production, which favors fatty acid and cholesterol synthesis. Similar effects of Mg(2+) were observed in HL-60 cells. These and previously published results suggest that in an hepatocyte culture model changes in cytoplasmic Mg(2+) content regulates glucose 6-phosphate utilization via glucose 6 phosphatase and hexose-6 phosphate dehydrogenase in alternative to glycolysis and glycogen synthesis. This alternative regulation might be of relevance in the transition from fed to fasted state.


Asunto(s)
Deshidrogenasas de Carbohidratos/metabolismo , Citoplasma/metabolismo , Retículo Endoplásmico/metabolismo , Magnesio/metabolismo , Regulación hacia Arriba , Deshidrogenasas de Carbohidratos/genética , Retículo Endoplásmico/enzimología , Activación Enzimática , Glucosa-6-Fosfato/metabolismo , Células HL-60 , Células Hep G2 , Humanos , Hígado/citología , Hígado/enzimología , Hígado/metabolismo , NADP/metabolismo , Oxidación-Reducción
15.
Alcohol Clin Exp Res ; 37(10): 1668-79, 2013 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-23763294

RESUMEN

BACKGROUND: Because the histological and biochemical progression of liver disease is similar in alcoholic steatohepatitis (ASH) and nonalcoholic steatohepatitis (NASH), we hypothesized that the genetic susceptibility to these liver diseases would be similar. To identify potential candidate genes that regulate the development of liver fibrosis, we studied a chromosome substitution strain (CSS-17) that contains chromosome 17 from the A/J inbred strain substituted for the corresponding chromosome on the C57BL/6J (B6) genetic background. Previously, we identified quantitative trait loci (QTLs) in CSS-17, namely obesity-resistant QTL 13 and QTL 15 (Obrq13 and Obrq15, respectively), that were associated with protection from diet-induced obesity and hepatic steatosis on a high-fat diet. METHODS: To test whether these or other CSS-17 QTLs conferred resistance to alcohol-induced liver injury and fibrosis, B6, A/J, CSS-17, and congenics 17C-1 and 17C-6 were either fed Lieber-DeCarli ethanol (EtOH)-containing diet or had carbon tetrachloride (CCl4 ) administered chronically. RESULTS: The congenic strain carrying Obrq15 showed resistance from alcohol-induced liver injury and liver fibrosis, whereas Obrq13 conferred susceptibility to liver fibrosis. From published deep sequencing data for chromosome 17 in the B6 and A/J strains, we identified candidate genes in Obrq13 and Obrq15 that contained single-nucleotide polymorphisms (SNPs) in the promoter region or within the gene itself. NADPH oxidase organizer 1 (Noxo1) and NLR family, CARD domain containing 4 (Nlrc4) showed altered hepatic gene expression in strains with the A/J allele at the end of the EtOH diet study and after CCl4 treatment. CONCLUSIONS: Aspects of the genetics for the progression of ASH are unique compared to NASH, suggesting that the molecular mechanisms for the progression of disease are at least partially distinct. Using these CSSs, we identified 2 candidate genes, Noxo1 and Nlrc4, which modulate genetic susceptibility in ASH.


Asunto(s)
Proteínas Reguladoras de la Apoptosis/genética , Proteínas de Unión al Calcio/genética , Cromosomas Humanos Par 17/genética , Hígado Graso Alcohólico/genética , Hígado Graso/genética , Predisposición Genética a la Enfermedad/genética , Proteínas/genética , Proteínas Adaptadoras Transductoras de Señales , Animales , Células Cultivadas , Hígado Graso/diagnóstico , Hígado Graso Alcohólico/diagnóstico , Femenino , Estudios de Asociación Genética/métodos , Humanos , Ratones , Ratones Congénicos , Ratones Endogámicos C57BL , Enfermedad del Hígado Graso no Alcohólico , Sitios de Carácter Cuantitativo/genética
16.
Mediators Inflamm ; 2013: 751374, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24453428

RESUMEN

Alcoholic liver disease (ALD) is characterized by increased hepatic lipid accumulation (steatosis) and inflammation with increased expression of proinflammatory cytokines. Two of these cytokines, interleukin-1 ß (IL-1 ß ) and IL-18, require activation of caspase-1 via members of the NOD-like receptor (NLR) family. These NLRs form an inflammasome that is activated by pathogens and signals released through local tissue injury or death. NLR family pyrin domain containing 3 (Nlrp3) and NLR family CARD domain containing protein 4 (Nlrc4) have been studied minimally for their role in the development of ALD. Using mice with gene targeted deletions for Nlrp3 (Nlrp3(-/-)) and Nlrc4 (Nlrc4(-/-)), we analyzed the response to chronic alcohol consumption. We found that Nlrp3(-/-) mice have more severe liver injury with higher plasma alanine aminotransferase (ALT) levels, increased activation of IL-18, and reduced activation of IL-1B. In contrast, the Nlrc4(-/-) mice had similar alcohol-induced liver injury compared to C57BL/6J (B6) mice but had greatly reduced activation of IL-1 ß . This suggests that Nlrp3 and Nlrc4 inflammasomes activate IL-1 ß and IL-18 via caspase-1 in a differential manner. We conclude that the Nlrp3 inflammasome is protective during alcohol-induced liver injury.


Asunto(s)
Proteínas Reguladoras de la Apoptosis/fisiología , Proteínas de Unión al Calcio/fisiología , Proteínas Portadoras/fisiología , Inflamasomas/fisiología , Hepatopatías Alcohólicas/etiología , Animales , Quimiocina CCL2/fisiología , Deficiencia de Colina/complicaciones , Interleucina-18/fisiología , Interleucina-1beta/fisiología , Metionina/deficiencia , Ratones , Ratones Endogámicos C57BL , Proteína con Dominio Pirina 3 de la Familia NLR , Factor de Transcripción STAT3/fisiología , Factor de Necrosis Tumoral alfa/fisiología
17.
Adv Exp Med Biol ; 789: 323-328, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23852511

RESUMEN

The coupling of upstream oxidative processes (glycolysis, beta-oxidation, CAC turnover) to mitochondrial oxidative phosphorylation (OXPHOS) under the driving conditions of energy demand by the cell results in the liberation of free energy as ATP. Perturbations in glycolytic CAC or OXPHOS can result in pathology or cell death. To better understand whole body energy expenditure during chronic ketosis, we used a diet-induced rat model of ketosis to determine if high-fat-carbohydrate-restricted "ketogenic" diet results in changes in total energy expenditure (TEE). Consistent with previous reports of increased energy expenditure in mice, we hypothesized that rats fed ketogenic diet for 3 weeks would result in increased resting energy expenditure due to alterations in metabolism associated with a "switch" in energy substrate from glucose to ketone bodies. The rationale is ketone bodies are a more efficient fuel than glucose. Indirect calorimetric analysis revealed a moderate increase in VO2 and decreased VCO2 and heat with ketosis. These results suggest ketosis induces a moderate uncoupling state and less oxidative efficiency compared to glucose oxidation.


Asunto(s)
Glucosa/metabolismo , Cuerpos Cetónicos/metabolismo , Animales , Calorimetría Indirecta/métodos , Dióxido de Carbono/metabolismo , Dieta Cetogénica , Cetosis/metabolismo , Masculino , Mitocondrias/metabolismo , Oxidación-Reducción , Oxígeno/metabolismo , Ratas , Ratas Wistar
18.
MedEdPORTAL ; 19: 11369, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38046813

RESUMEN

Introduction: Obesity is a multifactorial chronic disease and a major contributor to numerous health conditions. Despite the high prevalence, costs, and health effects of obesity, physicians are largely unprepared to treat it. Most medical students and residents lack sufficient training in obesity and obesity management. Methods: We evaluated a two-part team-based learning seminar (TBL) on obesity pathogenesis and treatment for first-year medical students at Case Western Reserve University School of Medicine (CWRU SOM). A questionnaire on attitudes toward obesity and self-perceived knowledge of obesity was administered before and after the TBL, utilizing Likert scales. Results: Of 183 medical students who attended both TBLs, 155 (85%) completed the baseline questionnaire, and 127 (69%) completed the postintervention questionnaire. Confidence in treating obesity increased significantly from preintervention (M = 2.7, SD = 1.0) to postintervention (M = 3.7, SD = 0.8). The attitude that obesity is caused by poor personal choices decreased significantly from preintervention (M = 2.8, SD = 0.9) to postintervention (M = 2.1, SD = 0.9). Self-perceived knowledge of obesity in all nine areas-epidemiology, energy homeostasis, etiologies, nutrition, physical activity, behavior, pharmacology, surgery, and language-increased significantly. Discussion: Despite obesity being one of the most prevalent health concerns, obesity education in medical school is scant. This TBL resulted in improved attitudes toward obesity and self-perceived knowledge of obesity among first-year medical students at CWRU SOM and offers a practical mechanism to introduce more obesity education into undergraduate medical curricula.


Asunto(s)
Facultades de Medicina , Estudiantes de Medicina , Humanos , Curriculum , Aprendizaje , Obesidad/epidemiología , Obesidad/terapia
19.
J Med Educ Curric Dev ; 10: 23821205231205953, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37915318

RESUMEN

OBJECTIVE: In recent years, significant steps have been made in integrating basic science and clinical medicine. There remains a gap in adding the third pillar of education: health systems science (HSS). Core clerkships represent an ideal learning venue to integrate all three. Students can experience the value of integrating basic science as they learn clinical medicine in environments where HSS is occurring all around them. METHODS: We outline the creation of Sciences and Art of Medicine Integrated (SAMI), a course that runs parallel with the clerkship year and integrates basic science and HSS with clinical medicine. A complete description of the planning and implementation of SAMI is provided. We include the participants and educational setting, the goals and objectives, and the structure of each session. To encourage the integration of basic science, HSS, and clinical medicine, students utilize a series of tools, described in detail. Examples of each tool are provided utilizing a case of a patient presenting with obstructive sleep apnea. RESULTS: We successfully implemented this course with positive reception from students. CONCLUSION: This course represents a step not only toward the integration of HSS with basic science and clinical medicine but also an advancement in training future clinicians to provide high-value care. Future curricular development must consider the validation of a measure of clinical reasoning that assesses a student's ability to think in a cognitively integrated fashion about basic science, HSS, and clinical medicine demonstrated by enhanced justification of clinical reasoning and a more holistic approach to planning patient care.

20.
J Biol Chem ; 286(46): 40013-24, 2011 Nov 18.
Artículo en Inglés | MEDLINE | ID: mdl-21917928

RESUMEN

Overexpression of the Ski oncogene induces oncogenic transformation of chicken embryo fibroblasts (CEFs). However, unlike most other oncogene-transformed cells, Ski-transformed CEFs (Ski-CEFs) do not display the classical Warburg effect. On the contrary, Ski transformation reduced lactate production and glucose utilization in CEFs. Compared with CEFs, Ski-CEFs exhibited enhanced TCA cycle activity, fatty acid catabolism through ß-oxidation, glutamate oxidation, oxygen consumption, as well as increased numbers and mass of mitochondria. Interestingly, expression of PPARγ, a key transcription factor that regulates adipogenesis and lipid metabolism, was dramatically elevated at both the mRNA and protein levels in Ski-CEFs. Accordingly, PPARγ target genes that are involved in lipid uptake, transport, and oxidation were also markedly up-regulated by Ski. Knocking down PPARγ in Ski-CEFs by RNA interference reversed the elevated expression of these PPARγ target genes, as well as the shift to oxidative metabolism and the increased mitochondrial biogenesis. Moreover, we found that Ski co-immunoprecipitates with PPARγ and co-activates PPARγ-driven transcription.


Asunto(s)
Pollos/metabolismo , Glucólisis/fisiología , PPAR gamma/metabolismo , Proteínas Proto-Oncogénicas/metabolismo , Adipogénesis/fisiología , Animales , Embrión de Pollo , Pollos/genética , Técnicas de Silenciamiento del Gen , Metabolismo de los Lípidos/fisiología , Mitocondrias/genética , Mitocondrias/metabolismo , Oxidación-Reducción , Consumo de Oxígeno/fisiología , PPAR gamma/genética , Proteínas Proto-Oncogénicas/genética , Transcripción Genética/fisiología
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