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1.
Cureus ; 14(10): e30067, 2022 Oct.
Article in English | MEDLINE | ID: mdl-36381756

ABSTRACT

A 19-year-old male presented with fatigue and dyspnea on exertion. He was diagnosed with acute T-cell lymphoblastic leukemia. After following the Group for Research on Adult Acute Lymphoblastic Leukemia (GRAALL) 2003 protocol that incorporates L-asparaginase (L-Asp) treatment, blood glucose levels became elevated for more than one year and insulin secretion was depleted. Anti-glutamic acid decarboxylase (GAD) and anti-islet antigen 2 (IA-2) antibody levels were both positive, which is rare. The patient's HLA genotype was sensitive for type 1 diabetes. L-Asp can cause transient hyperglycemia as a side effect. However, cases with the anti-GAD antibody have not been reported in L-Asp-induced diabetes. In summary, L-Asp-induced continuous hyperglycemia might be associated with a type 1 diabetes-related HLA genotype through elevations of anti-GAD and anti-IA-2 antibodies.

2.
Sci Rep ; 12(1): 11965, 2022 07 13.
Article in English | MEDLINE | ID: mdl-35831378

ABSTRACT

We aimed to investigate the status of falls and to identify important risk factors for falls in persons with type 2 diabetes (T2D) including the non-elderly. Participants were 316 persons with T2D who were assessed for medical history, laboratory data and physical capabilities during hospitalization and given a questionnaire on falls one year after discharge. Two different statistical models, logistic regression and random forest classifier, were used to identify the important predictors of falls. The response rate to the survey was 72%; of the 226 respondents, there were 129 males and 97 females (median age 62 years). The fall rate during the first year after discharge was 19%. Logistic regression revealed that knee extension strength, fasting C-peptide (F-CPR) level and dorsiflexion strength were independent predictors of falls. The random forest classifier placed grip strength, F-CPR, knee extension strength, dorsiflexion strength and proliferative diabetic retinopathy among the 5 most important variables for falls. Lower extremity muscle weakness, elevated F-CPR levels and reduced grip strength were shown to be important risk factors for falls in T2D. Analysis by random forest can identify new risk factors for falls in addition to logistic regression.


Subject(s)
Diabetes Mellitus, Type 2 , Diabetes Mellitus, Type 2/complications , Female , Humans , Logistic Models , Machine Learning , Male , Middle Aged , Muscle Strength/physiology , Risk Factors
3.
Biochim Biophys Acta Mol Basis Dis ; 1868(4): 166339, 2022 04 01.
Article in English | MEDLINE | ID: mdl-35017029

ABSTRACT

The pancreatic islet vasculature is of fundamental importance to the ß-cell response to obesity-associated insulin resistance. To explore islet vascular alterations in the pathogenesis of type 2 diabetes, we evaluated two insulin resistance models: ob/ob mice, which sustain large ß-cell mass and hyperinsulinemia, and db/db mice, which progress to diabetes due to secondary ß-cell compensation failure for insulin secretion. Time-dependent changes in islet vasculature and blood flow were investigated using tomato lectin staining and in vivo live imaging. Marked islet capillary dilation was observed in ob/ob mice, but this adaptive change was blunted in db/db mice. Islet blood flow volume was augmented in ob/ob mice, whereas it was reduced in db/db mice. The protein concentrations of total and phosphorylated endothelial nitric oxide synthase (eNOS) at Ser1177 were increased in ob/ob islets, while they were diminished in db/db mice, indicating decreased eNOS activity. This was accompanied by an increased retention of advanced glycation end-products in db/db blood vessels. Amelioration of diabetes by Elovl6 deficiency involved a restoration of capillary dilation, blood flow, and eNOS phosphorylation in db/db islets. Our findings suggest that the disability of islet capillary dilation due to endothelial dysfunction impairs local islet blood flow, which may play a role in the loss of ß-cell function and further exacerbate type 2 diabetes.


Subject(s)
Blood Vessels/metabolism , Islets of Langerhans/physiology , Animals , Blood Flow Velocity , Diabetes Mellitus, Type 2/pathology , Disease Models, Animal , Fatty Acid Elongases/deficiency , Fatty Acid Elongases/genetics , Female , Glycation End Products, Advanced/metabolism , Insulin/metabolism , Insulin Resistance , Islets of Langerhans/anatomy & histology , Islets of Langerhans/blood supply , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Mice, Obese , Nitric Oxide Synthase Type III/metabolism , Phosphorylation
4.
J Diabetes Res ; 2021: 9961612, 2021.
Article in English | MEDLINE | ID: mdl-34660814

ABSTRACT

AIM: We investigated the relationship between cognitive function and olfactory and physical functions in middle-aged persons with and without type 2 diabetes (T2D) to examine the potential of olfactory and physical functions as biomarkers for early cognitive impairment. METHODS: Enrolled were 70 T2D patients (age 40 to <65 y) and 81 age-matched control participants without diabetes. Cognitive function was assessed by the Montreal Cognitive Assessment (MoCA), Trail Making Test parts A and B (TMT-A/-B), Wisconsin Card Sorting Test (WCST), Quick Inventory of Depressive Symptomatology Self-Report (QIDS), and Starkstein Apathy Scale (SAS). Multiple linear regression analyses were performed. RESULTS: Odor identification was an independent determinant shown in the results of the TMT-A in the entire participant group and was independently associated with the MoCA and TMT-B in the T2D group. Balance capability assessed with a stabilometer was independently associated with all cognitive function tests except for QISD and SAS in the entire participant group and the T2D group and was independently associated with TMT-A in the control group. Knee extension strength was independently associated with the SAS in the entire participant group and the T2D group. CONCLUSIONS: Odor identification, balance capability, and knee extension strength were potential markers for cognitive decline in middle-aged persons with T2D.


Subject(s)
Cognition , Cognitive Dysfunction/physiopathology , Cognitive Dysfunction/psychology , Diabetes Mellitus, Type 2/physiopathology , Diabetes Mellitus, Type 2/psychology , Muscle Strength , Olfactory Perception , Postural Balance , Smell , Adult , Age Factors , Case-Control Studies , Cognitive Dysfunction/diagnosis , Cross-Sectional Studies , Diabetes Mellitus, Type 2/diagnosis , Early Diagnosis , Female , Health Status , Humans , Male , Middle Aged , Neuropsychological Tests , Physical Examination , Predictive Value of Tests , Risk Factors
5.
BMC Med Genet ; 21(1): 91, 2020 05 06.
Article in English | MEDLINE | ID: mdl-32375679

ABSTRACT

BACKGROUND: Renal hypouricemia (RHUC) is a hereditary disorder where mutations in SLC22A12 gene and SLC2A9 gene cause RHUC type 1 (RHUC1) and RHUC type 2 (RHUC2), respectively. These genes regulate renal tubular reabsorption of urates while there exist other genes counterbalancing the net excretion of urates including ABCG2 and SLC17A1. Urate metabolism is tightly interconnected with glucose metabolism, and SLC2A9 gene may be involved in insulin secretion from pancreatic ß-cells. On the other hand, a myriad of genes are responsible for the impaired insulin secretion independently of urate metabolism. CASE PRESENTATION: We describe a 67 year-old Japanese man who manifested severe hypouricemia (0.7 mg/dl (3.8-7.0 mg/dl), 41.6 µmol/l (226-416 µmol/l)) and diabetes with impaired insulin secretion. His high urinary fractional excretion of urate (65.5%) and low urinary C-peptide excretion (25.7 µg/day) were compatible with the diagnosis of RHUC and impaired insulin secretion, respectively. Considering the fact that metabolic pathways regulating urates and glucose are closely interconnected, we attempted to delineate the genetic basis of the hypouricemia and the insulin secretion defect observed in this patient using whole exome sequencing. Intriguingly, we found homozygous Trp258* mutations in SLC22A12 gene causing RHUC1 while concurrent mutations reported to be associated with hyperuricemia were also discovered including ABCG2 (Gln141Lys) and SLC17A1 (Thr269Ile). SLC2A9, that also facilitates glucose transport, has been implicated to enhance insulin secretion, however, the non-synonymous mutations found in SLC2A9 gene of this patient were not dysfunctional variants. Therefore, we embarked on a search for causal mutations for his impaired insulin secretion, resulting in identification of multiple mutations in HNF1A gene (MODY3) as well as other genes that play roles in pancreatic ß-cells. Among them, the Leu80fs in the homeobox gene NKX6.1 was an unreported mutation. CONCLUSION: We found a case of RHUC1 carrying mutations in SLC22A12 gene accompanied with compensatory mutations associated with hyperuricemia, representing the first report showing coexistence of the mutations with opposed potential to regulate urate concentrations. On the other hand, independent gene mutations may be responsible for his impaired insulin secretion, which contains novel mutations in key genes in the pancreatic ß-cell functions that deserve further scrutiny.


Subject(s)
Diabetes Complications/genetics , Glucose Transport Proteins, Facilitative/genetics , Organic Anion Transporters/genetics , Organic Cation Transport Proteins/genetics , Renal Tubular Transport, Inborn Errors/genetics , Urinary Calculi/genetics , Aged , Diabetes Complications/complications , Diabetes Complications/pathology , Glucose/metabolism , Hepatocyte Nuclear Factor 1-alpha/genetics , Heterozygote , Homeodomain Proteins/genetics , Homozygote , Humans , Insulin/biosynthesis , Insulin/genetics , Insulin Secretion/genetics , Insulin-Secreting Cells/metabolism , Insulin-Secreting Cells/pathology , Male , Mutation/genetics , Renal Tubular Transport, Inborn Errors/complications , Renal Tubular Transport, Inborn Errors/pathology , Uric Acid/metabolism , Urinary Calculi/complications , Urinary Calculi/pathology , Exome Sequencing
6.
Hepatology ; 71(5): 1609-1625, 2020 05.
Article in English | MEDLINE | ID: mdl-31529722

ABSTRACT

BACKGROUND AND AIMS: Dysfunctional hepatic lipid metabolism is a cause of nonalcoholic fatty liver disease (NAFLD), the most common chronic liver disorder worldwide, and is closely associated with insulin resistance and type 2 diabetes. ELOVL fatty acid elongase 6 (Elovl6) is responsible for converting C16 saturated and monounsaturated fatty acids (FAs) into C18 species. We have previously shown that Elovl6 contributes to obesity-induced insulin resistance by modifying hepatic C16/C18-related FA composition. APPROACH AND RESULTS: To define the precise molecular mechanism by which hepatic Elovl6 affects energy homeostasis and metabolic disease, we generated liver-specific Elovl6 knockout (LKO) mice. Unexpectedly, LKO mice were not protected from high-fat diet-induced insulin resistance. Instead, LKO mice exhibited higher insulin sensitivity than controls when consuming a high-sucrose diet (HSD), which induces lipogenesis. Hepatic patatin-like phospholipase domain-containing protein 3 (Pnpla3) expression was down-regulated in LKO mice, and adenoviral Pnpla3 restoration reversed the enhancement in insulin sensitivity in HSD-fed LKO mice. Lipidomic analyses showed that the hepatic ceramide(d18:1/18:0) content was lower in LKO mice, which may explain the effect on insulin sensitivity. Ceramide(d18:1/18:0) enhances protein phosphatase 2A (PP2A) activity by interfering with the binding of PP2A to inhibitor 2 of PP2A, leading to Akt dephosphorylation. Its production involves the formation of an Elovl6-ceramide synthase 4 (CerS4) complex in the endoplasmic reticulum and a Pnpla3-CerS4 complex on lipid droplets. Consistent with this, liver-specific Elovl6 deletion in ob/ob mice reduced both hepatic ceramide(d18:1/18:0) and PP2A activity and ameliorated insulin resistance. CONCLUSIONS: Our study demonstrates the key role of hepatic Elovl6 in the regulation of the acyl-chain composition of ceramide and that C18:0-ceramide is a potent regulator of hepatic insulin signaling linked to Pnpla3-mediated NAFLD.


Subject(s)
Ceramides/metabolism , Fatty Acid Elongases/physiology , Insulin Resistance/genetics , Liver/enzymology , Animals , Ceramides/chemistry , Dietary Sucrose/administration & dosage , Down-Regulation , Fatty Acid Elongases/genetics , Mice , Mice, Knockout , Non-alcoholic Fatty Liver Disease/genetics , Non-alcoholic Fatty Liver Disease/metabolism , Phospholipases A2, Calcium-Independent/metabolism , Protein Phosphatase 2/metabolism , Sphingosine N-Acyltransferase/metabolism
7.
Sci Rep ; 9(1): 5169, 2019 03 26.
Article in English | MEDLINE | ID: mdl-30914769

ABSTRACT

Brown adipose tissue (BAT) is an attractive therapeutic target for treating obesity and metabolic diseases. Octacosanol is the main component of policosanol, a mixture of very long chain aliphatic alcohols obtained from plants. The current study aimed to investigate the effect of octacosanol and policosanol on high-fat diet (HFD)-induced obesity. Mice were fed on chow, or HFD, with or without octacosanol or policosanol treatment for four weeks. HFD-fed mice showed significantly higher body weight and body fat compared with chow-fed mice. However, mice fed on HFD treated with octacosanol or policosanol (HFDo/p) showed lower body weight gain, body fat gain, insulin resistance and hepatic lipid content. Lower body fat gain after octacosanol or policosanol was associated with increased BAT activity, reduced expression of genes involved in lipogenesis and cholesterol uptake in the liver, and amelioration of white adipose tissue (WAT) inflammation. Moreover, octacosanol and policosanol significantly increased the expression of Ffar4, a gene encoding polyunsaturated fatty acid receptor, which activates BAT thermogenesis. Together, these results suggest that octacosanol and policosanol ameliorate diet-induced obesity and metabolic disorders by increasing BAT activity and improving hepatic lipid metabolism. Thus, these lipids represent promising therapeutic targets for the prevention and treatment of obesity and obesity-related metabolic disorders.


Subject(s)
Adipose Tissue, Brown/metabolism , Diet, High-Fat , Fatty Alcohols/therapeutic use , Liver/metabolism , Metabolic Diseases/drug therapy , Obesity/drug therapy , Obesity/prevention & control , Adipocytes/drug effects , Adipocytes/metabolism , Adipose Tissue, Brown/drug effects , Adipose Tissue, White/drug effects , Adipose Tissue, White/metabolism , Animals , Body Weight/drug effects , Fatty Alcohols/pharmacology , Fatty Liver/pathology , Gene Expression Regulation/drug effects , Inflammation/pathology , Insulin/blood , Liver/drug effects , Male , Metabolic Diseases/blood , Metabolic Diseases/genetics , Mice, Inbred C57BL , Obesity/blood , Obesity/genetics , Up-Regulation/drug effects
8.
FEBS Lett ; 593(4): 423-432, 2019 02.
Article in English | MEDLINE | ID: mdl-30659595

ABSTRACT

Glucocorticoids have various medical uses but are accompanied by side effects. The glucocorticoid receptor (GR) has been reported to regulate the clock genes, but the underlying mechanisms are incompletely understood. In this study, we focused on the suppressive effect of the GR on the expression of Rev-erbα (Nr1d1), an important component of the clock regulatory circuits. Here we show that the GR suppresses Rev-erbα expression via the formation of a complex with CLOCK and BMAL1, which binds to the E-boxes in the Nr1d1 promoter. In this GR-CLOCK-BMAL1 complex, the GR does not directly bind to DNA, which is referred to as tethering. These findings provide new insights into the role of the GR in the control of circadian rhythm.


Subject(s)
ARNTL Transcription Factors/metabolism , CLOCK Proteins/metabolism , Dexamethasone/administration & dosage , Nuclear Receptor Subfamily 1, Group D, Member 1/genetics , Receptors, Glucocorticoid/metabolism , Animals , Circadian Rhythm/drug effects , Dexamethasone/pharmacology , Gene Expression Regulation/drug effects , HEK293 Cells , Hep G2 Cells , Humans , Male , Mice , Nuclear Receptor Subfamily 1, Group D, Member 1/chemistry , Nuclear Receptor Subfamily 1, Group D, Member 1/metabolism , Promoter Regions, Genetic , Receptors, Glucocorticoid/agonists
9.
Diabetes Res Clin Pract ; 141: 237-243, 2018 Jul.
Article in English | MEDLINE | ID: mdl-29775676

ABSTRACT

BACKGROUND AND AIMS: Oxidized low-density lipoprotein (oxLDL) causes the development of atherosclerosis and kidney injury. Although circulating oxLDL levels were reportedly increased in type 2 diabetic patients with macroalbuminuria, it remains unclear whether albuminuria or the reduced glomerular filtration rate (GFR) is independently associated with the circulating oxLDL level. This study aimed to elucidate the association between the stage of diabetic nephropathy and serum malondialdehyde-modified LDL (MDA-LDL) and the ratio of MDA-LDL to LDL-cholesterol (MDA-LDL/LDL). METHODS AND RESULTS: This retroactive cross-sectional study used data from 402 patients with type 2 diabetes. Patients undergoing hemodialysis were excluded. Serum MDA-LDL levels were significantly increased with increases in severity of albuminuria (103 ±â€¯44 U/L, 109 ±â€¯54 U/L, and 135 ±â€¯72 U/L for normoalbuminuria, microalbuminuria, and macroalbuminuria, respectively; P for trend = 0.020) but not according to the estimated GFR (eGFR). An increased MDA-LDL/LDL ratio was significantly associated with both increased albuminuria (35 ±â€¯13, 37 ±â€¯14, and 40 ±â€¯15 for normoalbuminuria, microalbuminuria, and macroalbuminuria, respectively; P for trend = 0.003) and reduced eGFR (34 ±â€¯13, 36 ±â€¯13, 38 ±â€¯12, and 51 ±â€¯28 for grade 1, 2, 3 and 4, respectively; P for trend = 0.002). Multiple linear regression analysis showed that neither the albumin excretion rate nor eGFR but ln-transformed triglycerides and LDL-C levels were independent determinants of both serum MDA-LDL levels and MDA-LDL/LDL ratios. CONCLUSION: Serum MDA-LDL levels and MDA-LDL/LDL ratios were increased in those with dyslipidemia associated with diabetic kidney disease.


Subject(s)
Cholesterol, LDL/blood , Diabetes Mellitus, Type 2/blood , Diabetic Nephropathies/etiology , Malondialdehyde/metabolism , Cross-Sectional Studies , Diabetic Nephropathies/metabolism , Female , Humans , Male , Middle Aged , Retrospective Studies , Risk Factors
10.
Endocrinology ; 159(6): 2308-2323, 2018 06 01.
Article in English | MEDLINE | ID: mdl-29668871

ABSTRACT

Sterol regulatory element-binding protein (SREBP)-1a is a key transcription factor that activates the expression of genes involved in the synthesis of fatty acids, triglycerides (TGs), and cholesterol. Transgenic mice that overexpress the nuclear form of SREBP-1a under the control of the phosphoenolpyruvate carboxykinase promoter (Tg-1a) were previously shown to display a lipodystrophic phenotype characterized by enlarged and fatty livers, diminished peripheral white adipose tissue (WAT), and insulin resistance. In the current study, we crossed these Tg-1a mice with genetically obese (ob/ob) mice (Tg-1a;ob/ob) and examined change in fat distribution between liver and adipose tissues in severe obesity and mechanism underlying the lipodystrophic phenotype in mice with Tg-1a. Tg-1a;ob/ob mice developed more severe steatohepatitis but had reduced WAT mass and body weight compared with ob/ob mice. The reduction of WAT mass in Tg-1a and Tg-1a;ob/ob mice was accompanied by enhanced lipogenesis and lipid uptake in the liver, reduced plasma lipid levels, impaired adipocyte differentiation, reduced food intake, enhanced energy expenditure, and extended macrophage infiltration and fibrosis in WAT. Despite the improved glucose tolerance, Tg-1a;ob/ob mice showed severe peripheral insulin resistance. Adenoviral hepatic expression of SREBP-1a mimicked these phenotypes. The "fat steal"-like lipodystrophy phenotype of the Tg-1a;ob/ob model demonstrates that hepatic SREBP-1a activation has a strong impact on the partition of TG accumulation, resulting in adipose-tissue remodeling by inflammation and fibrosis and insulin resistance.


Subject(s)
Insulin Resistance/genetics , Lipodystrophy/genetics , Obesity/genetics , Sterol Regulatory Element Binding Protein 1/genetics , Animals , Cells, Cultured , Disease Progression , Female , Lipodystrophy/complications , Lipodystrophy/pathology , Male , Metabolic Syndrome/genetics , Metabolic Syndrome/pathology , Mice , Mice, Inbred C57BL , Mice, Obese , Mice, Transgenic , Obesity/complications , Obesity/pathology
11.
J Phys Ther Sci ; 30(1): 86-91, 2018 Jan.
Article in English | MEDLINE | ID: mdl-29410573

ABSTRACT

[Purpose] The efficacy of a stabilometer-based index of postural stability (IPS) as an indicator of dynamic balance ability was investigated. [Subjects and Methods] Using a stabilometer, we calculated the IPS in 583 healthy subjects (178 males, 405 females) under two conditions (open eyes/hard surface, OE/HS; closed eyes/soft surface, CE/SS). [Results] Results revealed a negative relation between IPS and age. IPS (OE/HS) began to decrease at middle-age (40-60 years old), and then decreased more rapidly during elderly ages (>60 years old). On the other hand, IPS (CE/SS) decreased linearly with increasing age. There was no gender difference between the two IPSs. [Conclusion] These results suggest that IPS can evaluate balance ability quantitatively and without a ceiling effect. It was concluded that IPS (OE/HS) indicates comprehensive balance ability, while IPS (CE/SS) reveals balance ability without compensation by visual acuity and plantar superficial sense.

12.
FEBS Lett ; 592(3): 422-433, 2018 02.
Article in English | MEDLINE | ID: mdl-29331016

ABSTRACT

The SNP rs7903146 at the transcription factor 7-like 2 (TCF7L2) locus is established as the strongest known genetic marker for type 2 diabetes via genome-wide association studies. However, the functional SNPs regulating TCF7L2 expression remain unclear. Here, we show that the SNP rs7074440 is a candidate functional SNP highly linked with rs7903146. A reporter plasmid with rs7074440 normal allele sequence exhibited 15-fold higher luciferase activity compared with risk allele sequence in hepatocytes, demonstrating a strong enhancer activity at rs7074440. Additionally, we identified C-FOS as an activator binding to the rs7074440 enhancer using a TFEL genome-wide screen method. Consistently, knockdown of C-FOS significantly reduced TCF7L2 expression in hepatocytes. Collectively, a novel enhancer regulating TCF7L2 expression was revealed through searching for functional SNPs.


Subject(s)
Diabetes Mellitus, Type 2/genetics , Hepatocytes/metabolism , Polymorphism, Single Nucleotide , Proto-Oncogene Proteins c-fos/metabolism , Transcription Factor 7-Like 2 Protein/genetics , Animals , Cell Line , Female , Gene Expression , HEK293 Cells , Hep G2 Cells , Hepatocytes/cytology , Humans , Male , Mice
13.
Intern Med ; 57(7): 979-985, 2018 Apr 01.
Article in English | MEDLINE | ID: mdl-29269645

ABSTRACT

We herein report a case of pheochromocytoma occurring in the course of Parkinson's disease. The coexistence of these two disease is extremely rare, with only four cases hitherto reported across the public databases. It is also noteworthy that biochemical tests, which are critical for the diagnosis of pheochromocytoma, are severely confounded by dopaminergic medications for Parkinson's disease, highlighting the importance of image-based modalities in this setting. We further attempted to gain insight into the potential molecular mechanisms, proposing that hypoxia-inducible factor signaling could make these two diseases mutually exclusive, while excessive reactive oxygen species could enable their coexistence.


Subject(s)
Adrenal Gland Neoplasms/diagnostic imaging , Dopamine Agents/adverse effects , Dopamine Agents/therapeutic use , Parkinson Disease/diagnosis , Parkinson Disease/drug therapy , Parkinson Disease/physiopathology , Pheochromocytoma/diagnostic imaging , Aged , Asian People , Humans , Male , Rare Diseases/diagnosis , Rare Diseases/therapy , Signal Transduction
14.
Biochem Biophys Res Commun ; 493(1): 40-45, 2017 11 04.
Article in English | MEDLINE | ID: mdl-28928093

ABSTRACT

Sodium-glucose cotransporter 2 (SGLT2) inhibitors have both anti-diabetic and anti-obesity effects. However, the precise mechanism of the anti-obesity effect remains unclear. We previously demonstrated that the glycogen depletion signal triggers lipolysis in adipose tissue via liver-brain-adipose neurocircuitry. In this study, therefore, we investigated whether the anti-obesity mechanism of SGLT2 inhibitor is mediated by this mechanism. Diet-induced obese mice were subjected to hepatic vagotomy (HVx) or sham operation and loaded with high fat diet containing 0.015% tofogliflozin (TOFO), a highly selective SGLT2 inhibitor, for 3 weeks. TOFO-treated mice showed a decrease in fat mass and the effect of TOFO was attenuated in HVx group. Although both HVx and sham mice showed a similar level of reduction in hepatic glycogen by TOFO treatment, HVx mice exhibited an attenuated response in protein phosphorylation by protein kinase A (PKA) in white adipose tissue compared with the sham group. As PKA pathway is known to act as an effector of the liver-brain-adipose axis and activate triglyceride lipases in adipocytes, these results indicated that SGLT2 inhibition triggered glycogen depletion signal and actuated liver-brain-adipose axis, resulting in PKA activation in adipocytes. Taken together, it was concluded that the effect of SGLT2 inhibition on weight loss is in part mediated via the liver-brain-adipose neurocircuitry.


Subject(s)
Adipose Tissue/physiology , Benzhydryl Compounds/administration & dosage , Brain/physiology , Glucosides/administration & dosage , Liver/physiology , Sodium-Glucose Transporter 2 Inhibitors , Sodium-Glucose Transporter 2/metabolism , Weight Loss/physiology , Adipose Tissue/drug effects , Adipose Tissue/innervation , Animals , Anti-Obesity Agents/administration & dosage , Brain/drug effects , Liver/drug effects , Liver/innervation , Male , Mice , Mice, Inbred C57BL , Vagotomy , Vagus Nerve/drug effects , Vagus Nerve/physiology , Vagus Nerve/surgery
15.
Diabetes ; 66(7): 1833-1846, 2017 07.
Article in English | MEDLINE | ID: mdl-28461456

ABSTRACT

Dysfunctional fatty acid (FA) metabolism plays an important role in the pathogenesis of ß-cell dysfunction and loss of ß-cell mass in type 2 diabetes (T2D). Elovl6 is a microsomal enzyme that is responsible for converting C16 saturated and monounsaturated FAs into C18 species. We previously showed that Elovl6 played a critical role in the development of obesity-induced insulin resistance by modifying FA composition. To further define its role in T2D development, we assessed the effects of Elovl6 deletion in leptin receptor-deficient C57BL/KsJ db/db mice, a model of T2D. The db/db;Elovl6-/- mice had a markedly increased ß-cell mass with increased proliferation and decreased apoptosis, an adaptive increase in insulin, and improved glycemic control. db/db islets were characterized by a prominent elevation of oleate (C18:1n-9), cell stress, and inflammation, which was completely suppressed by Elovl6 deletion. As a mechanistic ex vivo experiment, isolated islets from Elovl6-/- mice exhibited reduced susceptibility to palmitate-induced inflammation, endoplasmic reticulum stress, and ß-cell apoptosis. In contrast, oleate-treated islets resulted in impaired glucose-stimulated insulin secretion with suppressed related genes irrespective of the Elovl6 gene. Taken together, Elovl6 is a fundamental factor linking dysregulated lipid metabolism to ß-cell dysfunction, islet inflammation, and ß-cell apoptosis in T2D, highlighting oleate as the potential culprit of ß-cell lipotoxicity.


Subject(s)
Acetyltransferases/deficiency , Acetyltransferases/genetics , Diabetes Mellitus, Experimental/genetics , Diabetes Mellitus, Type 2/genetics , Insulin-Secreting Cells/metabolism , Insulin/metabolism , Acetyltransferases/physiology , Animals , Apoptosis/genetics , Blood Glucose/metabolism , Diabetes Mellitus, Experimental/metabolism , Diabetes Mellitus, Type 2/metabolism , Endoplasmic Reticulum Stress , Fatty Acid Elongases , Fatty Acids, Nonesterified/metabolism , Female , Immunohistochemistry , In Vitro Techniques , Inflammation/chemically induced , Inflammation/genetics , Insulin Secretion , Insulin-Secreting Cells/drug effects , Insulin-Secreting Cells/pathology , Islets of Langerhans/drug effects , Islets of Langerhans/metabolism , Islets of Langerhans/pathology , Lipid Metabolism/genetics , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Oleic Acid/pharmacology , Organ Size , Palmitates/adverse effects , Real-Time Polymerase Chain Reaction , Receptors, Leptin/genetics
16.
J Diabetes Investig ; 8(4): 446-452, 2017 Jul.
Article in English | MEDLINE | ID: mdl-28084058

ABSTRACT

AIMS/INTRODUCTION: Peroxisome proliferator-activated receptor-α (PPARα) is a therapeutic target for hyperlipidemia. K-877 is a new selective PPARα modulator (SPPARMα) that activates PPARα transcriptional activity. The aim of the present study was to assess the effects of K-877 on lipid metabolism in vitro and in vivo compared with those of classical PPARα agonists. MATERIALS AND METHODS: To compare the effects of K-877 on PPARα transcriptional activity with those of the classical PPARα agonists Wy14643 (Wy) and fenofibrate (Feno), the cell-based PPARα transactivation luciferase assay was carried out. WT and Ppara-/- mice were fed with a moderate-fat (MF) diet for 6 days, and methionine-choline-deficient (MCD) diet for 4 weeks containing Feno or K-877. RESULTS: In luciferase assays, K-877 activated PPARα transcriptional activity more efficiently than the classical PPARα agonists Feno and Wy. After being fed MF diet containing 0.001% K-877 or 0.2% Feno for 6 days, mice in the K-877 group showed significant increases in the expression of Ppara and its target genes, leading to marked reductions in plasma triglyceride levels compared with those observed in Feno-treated animals. These K-877 effects were blunted in Ppara-/- mice, confirming that K-877 activates PPARα. In further experiments, K-877 (0.00025%) and Feno (0.1%) equally improved the pathology of MCD diet-induced non-alcoholic fatty liver disease, with increased expression of hepatic fatty acid oxidation genes. CONCLUSIONS: The present data show that K-877 is an attractive PPARα-modulating drug and can efficiently reduce plasma triglyceride levels, thereby alleviating the dysregulation of lipid metabolism.


Subject(s)
Benzoxazoles/pharmacology , Butyrates/pharmacology , Gene Expression/drug effects , Lipid Metabolism/drug effects , Liver/drug effects , PPAR alpha/agonists , Animals , Cell Line , Drug Evaluation, Preclinical , Fenofibrate/pharmacology , Hypolipidemic Agents/pharmacology , Liver/metabolism , Male , Mice, Inbred C57BL , Pyrimidines/pharmacology , X-Box Binding Protein 1/metabolism
17.
Sci Rep ; 6: 39182, 2016 12 16.
Article in English | MEDLINE | ID: mdl-27982131

ABSTRACT

CREB3L3 is involved in fatty acid oxidation and ketogenesis in a mutual manner with PPARα. To evaluate relative contribution, a combination of knockout and transgenic mice was investigated. On a ketogenic-diet (KD) that highlights capability of hepatic ketogenesis, Creb3l3-/- mice exhibited reduction of expression of genes for fatty oxidation and ketogenesis comparable to Ppara-/- mice. Most of the genes were further suppressed in double knockout mice indicating independent contribution of hepatic CREB3L3. During fasting, dependency of ketogenesis on CREB3L3 is lesser extents than Ppara-/- mice suggesting importance of adipose PPARα for supply of FFA and hyperlipidemia in Creb3l3-/- mice. In conclusion CREB3L3 plays a crucial role in hepatic adaptation to energy starvation via two pathways: direct related gene regulation and an auto-loop activation of PPARα. Furthermore, as KD-fed Creb3l3-/- mice exhibited severe fatty liver, activating inflammation, CREB3L3 could be a therapeutic target for NAFLD.


Subject(s)
Cyclic AMP Response Element-Binding Protein/genetics , Fatty Acids/chemistry , PPAR alpha/genetics , Adenoviridae/genetics , Animals , Blood Glucose/analysis , Carnitine O-Palmitoyltransferase/chemistry , Carnitine O-Palmitoyltransferase/genetics , Carnitine O-Palmitoyltransferase/metabolism , Cell Line, Tumor , Cyclic AMP Response Element-Binding Protein/deficiency , Diet, Ketogenic , Energy Metabolism , Fatty Acids/metabolism , Fatty Liver/etiology , Fatty Liver/metabolism , Fibroblast Growth Factors/blood , Gene Expression , Lipid Peroxidation , Liver/metabolism , Liver/pathology , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Mice, Transgenic , PPAR alpha/deficiency , Plasmids/genetics , Plasmids/metabolism , Promoter Regions, Genetic , RNA, Messenger/metabolism , Triglycerides/blood
18.
Mol Metab ; 5(11): 1092-1102, 2016 11.
Article in English | MEDLINE | ID: mdl-27818935

ABSTRACT

OBJECTIVE: The transcription factor cyclic AMP-responsive element-binding protein H (CREBH, encoded by Creb3l3) is highly expressed in the liver and small intestine. Hepatic CREBH contributes to glucose and triglyceride metabolism by regulating fibroblast growth factor 21 (Fgf21) expression. However, the intestinal CREBH function remains unknown. METHODS: To investigate the influence of intestinal CREBH on cholesterol metabolism, we compared plasma, bile, fecal, and tissue cholesterol levels between wild-type (WT) mice and mice overexpressing active human CREBH mainly in the small intestine (CREBH Tg mice) under different dietary conditions. RESULTS: Plasma cholesterol, hepatic lipid, and cholesterol crystal formation in the gallbladder were lower in CREBH Tg mice fed a lithogenic diet (LD) than in LD-fed WTs, while fecal cholesterol output was higher in the former. These results suggest that intestinal CREBH overexpression suppresses cholesterol absorption, leading to reduced plasma cholesterol, limited hepatic supply, and greater excretion. The expression of Niemann-Pick C1-like 1 (Npc1l1), a rate-limiting transporter mediating intestinal cholesterol absorption, was reduced in the small intestine of CREBH Tg mice. Adenosine triphosphate-binding cassette transporter A1 (Abca1), Abcg5/8, and scavenger receptor class B, member 1 (Srb1) expression levels were also reduced in CREBH Tg mice. Promoter assays revealed that CREBH directly regulates Npc1l1 expression. Conversely, CREBH null mice exhibited higher intestinal Npc1l1 expression, elevated plasma and hepatic cholesterol, and lower fecal output. CONCLUSION: Intestinal CREBH regulates dietary cholesterol flow from the small intestine by controlling the expression of multiple intestinal transporters. We propose that intestinal CREBH could be a therapeutic target for hypercholesterolemia.


Subject(s)
Cholesterol, Dietary/metabolism , Cyclic AMP Response Element-Binding Protein/physiology , Hypercholesterolemia/metabolism , Membrane Transport Proteins/metabolism , ATP Binding Cassette Transporter, Subfamily G, Member 5 , ATP Binding Cassette Transporter, Subfamily G, Member 8 , ATP-Binding Cassette Transporters , Animals , Humans , Hypercholesterolemia/drug therapy , Lipoproteins , Membrane Proteins , Mice
19.
PLoS One ; 11(6): e0157580, 2016.
Article in English | MEDLINE | ID: mdl-27333187

ABSTRACT

Non-alcoholic fatty liver disease (NAFLD), the hepatic manifestation of metabolic syndrome, can progress to steatohepatitis (NASH) and advanced liver damage, such as that from liver cirrhosis and cancer. Recent studies have shown the benefits of consuming n-3 polyunsaturated fatty acids (PUFAs) for the treatment of NAFLD. In the present study, we investigated and compared the effects of the major n-3 PUFAs-eicosapentaenoic acid (EPA, C20:5) and docosahexaenoic acid (DHA, C22:6)-in preventing atherogenic high-fat (AHF) diet-induced NAFLD. Mice were fed the AHF diet supplemented with or without EPA or DHA for four weeks. Both EPA and DHA reduced the pathological features of AHF diet-induced NASH pathologies such as hepatic lobular inflammation and elevated serum transaminase activity. Intriguingly, EPA had a greater hepatic triacylglycerol (TG)-reducing effect than DHA. In contrast, DHA had a greater suppressive effect than EPA on AHF diet-induced hepatic inflammation and ROS generation, but no difference in fibrosis. Both EPA and DHA could be effective for treatment of NAFLD and NASH. Meanwhile, the two major n-3 polyunsaturated fatty acids might differ in a relative contribution to pathological intermediate steps towards liver fibrosis.


Subject(s)
Atherosclerosis/pathology , Diet, High-Fat/adverse effects , Docosahexaenoic Acids/therapeutic use , Eicosapentaenoic Acid/therapeutic use , Non-alcoholic Fatty Liver Disease/chemically induced , Non-alcoholic Fatty Liver Disease/drug therapy , Animals , Cholesterol/metabolism , Docosahexaenoic Acids/pharmacology , Eicosapentaenoic Acid/pharmacology , Inflammation/complications , Inflammation/pathology , Lipid Metabolism , Liver/injuries , Liver/metabolism , Liver/pathology , Male , Mice, Inbred C57BL , Non-alcoholic Fatty Liver Disease/metabolism , Non-alcoholic Fatty Liver Disease/pathology , Oxidative Stress , Phenotype , RNA, Messenger/genetics , RNA, Messenger/metabolism
20.
Sci Rep ; 6: 27857, 2016 06 13.
Article in English | MEDLINE | ID: mdl-27291420

ABSTRACT

cAMP responsive element binding protein 3-like 3 (CREB3L3), a transcription factor expressed in the liver and small intestine, governs fasting-response energy homeostasis. Tissue-specific CREB3L3 knockout mice have not been generated till date. To our knowledge, this is the first study using the one-step CRISPR/Cas9 system to generate CREB3L3 floxed mice and subsequently obtain liver- and small intestine-specific Creb3l3 knockout (LKO and IKO, respectively) mice. While LKO mice as well as global KO mice developed hypertriglyceridemia, LKO mice exhibited hypercholesterolemia in contrast to hypocholesterolemia in global KO mice. LKO mice demonstrated up-regulation of hepatic Srebf2 and its corresponding target genes. No phenotypic differences were observed between IKO and floxed mice. Severe liver injury was observed in LKO mice fed a methionine-choline deficient diet, a model for non-alcoholic steatohepatitis. These results provide new evidence regarding the hepatic CREB3L3 role in plasma triglyceride metabolism and hepatic and intestinal CREB3L3 contributions to cholesterol metabolism.


Subject(s)
CRISPR-Cas Systems/genetics , Cyclic AMP Response Element-Binding Protein/genetics , Hepatitis, Animal/etiology , Hyperlipidemias/etiology , Liver/metabolism , Animals , Cholesterol/metabolism , Choline Deficiency , Cyclic AMP Response Element-Binding Protein/deficiency , Female , Hepatitis, Animal/metabolism , Hyperlipidemias/metabolism , Hyperlipidemias/veterinary , Insulin/blood , Intestine, Small/metabolism , Liver/pathology , Male , Methionine/deficiency , Mice , Mice, Inbred C57BL , Mice, Knockout , Non-alcoholic Fatty Liver Disease/etiology , Non-alcoholic Fatty Liver Disease/metabolism , Sterol Regulatory Element Binding Protein 2/metabolism , Triglycerides/blood , Triglycerides/metabolism , Up-Regulation
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