Oxidative stress is associated with obesity and may be accompanied by liver insulin resistance and mitochondrial dysfunction. Decreased mitochondrial respiratory chain enzymatic activities and decreased insulin metabolic signaling may promote these maladaptive changes. In this context, exenatide has been reported to reduce hepatic lipid deposition, improve insulin sensitivity and improve mitochondrial dysfunction. We hypothesized that exenatide would attenuate mitochondrial dysfunction by reducing hepatic lipid deposition, blunting oxidant stress and promoting insulin metabolic signaling in a high fat diet-induced model of obesity and insulin resistance. Sixteen-week-old male C57BL/6 diet-induced obese (DIO) mices and age-matched standard diet (STD) mices were treated with exenatide (10 μg/kg twice a day) for 28 days. Compared with untreated STD mice, untreated DIO mice exhibited deposited excessive lipid in liver and produced the oxidative stress in conjunction with insulin resistance, abnormal hepatic cells and mitochondrial histoarchitecture, mitochondrial dysfunction and reduced organism metabolism. Exenatide reduced hepatic steatosis, decreased oxidative stress, and improved insulin resistance in DIO mice, in concert with improvements in the insulin metabolic signaling, mitochondrial respiratory chain enzymatic activation, adenine nucleotide production, organism metabolism and weight gain. Results support the hypothesis that exenatide reduces hepatic cells and mitochondrial structural anomaly and improves insulin resistance in concert with improvements in insulin sensitivity and mitochondrial function activation, concomitantly with reductions in oxidative stress.

ABSTRACT Osteopetrosis (OMIM: 611497), literally “stone bone,” is a group of inherited bone disorders characterized by increased skeletal mass due to defective osteoclast function. A patient who reported a history of frequent fractures, weakness and fatigue was admitted to our hospital in 2011. The patient presented with the typical features of osteopetrosis: fractures after minor trauma, early tooth loss, anemia, hepatosplenomegaly, and a generalized increase in bone mineral density (BMD). Aside from his father's complaint of excessive tooth loss, his mother, two sisters, son, and daughter were healthy. Blood samples of the family members were drawn for genetic analyses. The entire coding region and adjacent splice sites of the pleckstrin homology domain–containing family M (with RUN domain) member 1 (PLEKHM1) gene were sequenced. One mutation, a heterozygous deletion mutation in exon 11 (c.3051_3052delCA), was identified in the patient but not in his relatives. The mutation leads to a translation product with a highly impaired Rubicon homology domain. Co-immunoprecipitation and immunofluorescence analyses using HEK293 cells showed that overexpression of a PLEKHM1 CA-deletion mutant resulted in a dramatic decrease in the interaction between PLEKHM1 and the small GTPase Rab7 compared to wild-type PLEKHM1. The normal processes of endocytosis and autophagy were disturbed in cells expressing the mutant (transfected HEK293 and U937 cells), as indicated by epidermal growth factor receptor (EGFR) degradation and an altered LC3-I/II ratio, respectively, which may lead to a defect in osteoclast function. A four-year follow-up study of the patient showed that the PLEKHM1-dependent osteopetrosis was relatively malignant, with significant symptoms of pancytopenia and hepatosplenomegaly. © 2016 American Society for Bone and Mineral Research.

OBJECTIVE:To investigate the role of Apaf-1 gene promoter methylation and apoptosis inhibitor protein Apollon in pathogenesis of acute leukemia (AL) and their clinical significance. METHODS:Methylation specific PCR (MSP) was used to detect the methylation status of Apaf-1 gene promoter in 53 AL patients (28 AML, 10 ALL and 15 relapsed) and 10 healthy or nonmalignant blood diseases patients as control. RT-PCR was used to detect the expression levels of Apaf-1 mRNA and immunocytochemistry to detect the expression levels of Apollon protein. RESULTS:The abnromal methylation of Apaf-1 gene promotor in AL was 18/53(33.9%). No Apaf-1 mRNA was detected in methylation positive patients. Only one case in healthy and nonmalignant individuals was deletion of Apaf-1 mRNA expression without abnormal methylation. The positive methylation rate in AL bone marrow mononuclear cells was significantly higher than that in controls (P < 0.05). The expressin levels of Apollon protein in AL patients was higher than that in control (P < 0.05). The positive methylation ratio and Apollon protein level were higher in white blood cell count > 10 × 10(9)/L than in ≤ 10 × 10(9)/L (P < 0.05). There is a positive correlaiton between positive methylation ratio and Apollon protein expression in AL patients. CONCLUSION:Abnormal methylation of Apaf-1 gene promotor and high expression of Apollon might involved in leukemogenesis.