Methylation patterns of circulating cell-free DNA (cfDNA) contain rich information about recent cell death events in the body. Here, we present an approach for unbiased determination of the tissue ...origins of cfDNA, using a reference methylation atlas of 25 human tissues and cell types. The method is validated using in silico simulations as well as in vitro mixes of DNA from different tissue sources at known proportions. We show that plasma cfDNA of healthy donors originates from white blood cells (55%), erythrocyte progenitors (30%), vascular endothelial cells (10%) and hepatocytes (1%). Deconvolution of cfDNA from patients reveals tissue contributions that agree with clinical findings in sepsis, islet transplantation, cancer of the colon, lung, breast and prostate, and cancer of unknown primary. We propose a procedure which can be easily adapted to study the cellular contributors to cfDNA in many settings, opening a broad window into healthy and pathologic human tissue dynamics.
Differences in white adipose tissue (WAT) lipid turnover between the visceral (vWAT) and subcutaneous (sWAT) depots may cause metabolic complications in obesity. Here we compare triglyceride age and, ...thereby, triglyceride turnover in vWAT and sWAT biopsies from 346 individuals and find that subcutaneous triglyceride age and storage capacity are increased in overweight or obese individuals. Visceral triglyceride age is only increased in excessively obese individuals and associated with a lower lipid removal capacity. Thus, although triglyceride storage capacity in sWAT is higher than in vWAT, the former plateaus at substantially lower levels of excess WAT mass than vWAT. In individuals with central or visceral obesity, lipid turnover is selectively increased in vWAT. Obese individuals classified as 'metabolically unhealthy' (according to ATPIII criteria) who have small subcutaneous adipocytes exhibit reduced triglyceride turnover. We conclude that excess WAT results in depot-specific differences in lipid turnover and increased turnover in vWAT and/or decreased turnover in sWAT may result in metabolic complications of overweight or obesity.
Summary
Purpose: Generalized absence seizures are characterized by bilateral spike‐wave discharges (SWDs), particularly in the frontoparietal cortical region. In WAG/Rij and GAERS rats with absence ...epilepsy, recent evidence indicates that SWDs arise first from the lateral somatosensory cortex (LSC), that is, the cortical focus theory. To further understand the cortical role in SWD generation, two epileptic rat models were assessed.
Methods: Two models, Long‐Evans rats with spontaneous SWDs and Wistar rats with low‐dose pentylenetetrazol‐induced SWDs (20 mg/kg, i.p.), were administered intracortical or intrathalamic ethosuximide (ESM) or saline. Electroencephalographic recordings were analyzed before and after intracranial microinfusion to evaluate onset, frequency, and duration of SWDs.
Key Findings: In both epileptic rat models, ESM in the LSC significantly reduced SWD number, shortened SWD duration, and delayed SWD onset compared to saline. By contrast, ESM in the medial somatosensory cortex had little effect compared to saline. Intrathalamic infusion of ESM only delayed SWD onset.
Significance: These findings suggest that the LSC may be essential for the occurrence of SWDs. Our data support the cortical focus theory for the generation of absence seizures.
The worldwide obesity epidemic
makes it important to understand how lipid turnover (the capacity to store and remove lipids) regulates adipose tissue mass. Cross-sectional studies have shown that ...excess body fat is associated with decreased adipose lipid removal rates
. Whether lipid turnover is constant over the life span or changes during long-term weight increase or loss is unknown. We determined the turnover of fat cell lipids in adults followed for up to 16 years, by measuring the incorporation of nuclear bomb test-derived
C in adipose tissue triglycerides. Lipid removal rate decreases during aging, with a failure to reciprocally adjust the rate of lipid uptake resulting in weight gain. Substantial weight loss is not driven by changes in lipid removal but by the rate of lipid uptake in adipose tissue. Furthermore, individuals with a low baseline lipid removal rate are more likely to remain weight-stable after weight loss. Therefore, lipid turnover adaptation might be important for maintaining pronounced weight loss. Together these findings identify adipose lipid turnover as an important factor for the long-term development of overweight/obesity and weight loss maintenance in humans.
Obesity, defined as an excessive accumulation of body fat, is considered one of the major health challenges facing the world today. Adipocyte and lipid turnover determine the number and the size of ...fat cells, respectively. Therefore, understanding the dynamics of adipocyte and lipid turnover will provide important insights into the factors regulating the size of the fat mass. Adipose tissue is not uniformly distributed throughout the body, and the regional differences in turnover may contribute to the link between body fat distribution and increased risk of metabolic complications. Several factors such as sex and age are also known to impact fat accumulation, however, their influence on adipose tissue turnover dynamics are unclear. In this thesis, we provide a comprehensive analysis of age and turnover dynamics of both adipocytes and lipids in human subcutaneous (scWAT) and visceral (vWAT) adipose tissue, by measuring the integration of 14C derived from nuclear bomb tests into genomic DNA and lipids, across the lifespan. The effects of fat mass distribution, sex, age and BMI were investigated for their influence on adipose tissue turnover, as well as interventions such as weight loss over time.In Paper I, we examined the differences in lipid turnover in scWAT and vWAT in individuals with a range of BMIs. While scWAT lipid age and storage capacity were increased in overweight and obese individuals, lipid age in vWAT was increased only in the excessively obese individuals and was associated with a reduced lipid removal rate. Moreover, in central or visceral obese individuals, lipid turnover was selectively increased in vWAT. Metabolically unhealthy obese individuals with small scWAT adipocytes exhibited reduced lipid turnover. In conclusion, excess body fat mass results in a depot-specific reduction in lipid turnover. Increased lipid turnover in vWAT and/or decreased lipid turnover in scWAT may contribute to metabolic complications of overweight or obesity.In Paper II, we explored lipid turnover dynamics in adults who were followed for up to 16 years (mean follow-up time 13 years) or 5 years following significant weight loss. Lipid removal rate decreased with aging, and a failure to reciprocally adjust for lipid uptake rate resulted in weight gain. Substantial weight loss was primarily driven by a reduced rate of lipid uptake. Surprisingly, individuals with a low baseline lipid removal rate were more likely to maintain the weight loss 5 years following weight-loss surgery. Taken together, these findings identify lipid turnover as an important regulator of long-term obesity development and weight loss maintenance.In Paper III, we compared the age of adipocytes and lipid in human scWAT and vWAT. vWAT adipocytes were found to be older than scWAT adipocytes, suggesting regional differences in the adipocyte death rate. Subject sex, age and body fat mass also had a significant impact on adipocyte age. Females had a slower death rate of adipocytes than males, and age and BMI inversely correlated with the adipocyte death rate. Lipid removal rate was also found to be lower in females than males, and decreased with aging in both depots. In summary, these results identify adipocyte and lipid removal rates as important factors contributing to regional differences in fat distribution, and that sex, age and BMI-dependent differences in turnover dynamics influence one’s risk developing obesity-associated metabolic complications.Taken together, this thesis provides a deeper characterization of adipocyte and lipid age and turnover dynamics in humans. Furthermore, it highlights regional differences in adipocyte and lipid turnover and the important link to total fat mass accumulation and distribution, in both lean and obese individuals, females and males, and the young and the elderly.
Abstract only
In order to investigate whether exercise ameliorates insulin‐ and insulin‐like growth factor‐1 (IGF‐1)‐mediated vasorelaxation in the diabetes, male Wistar rats were randomly divided ...into non‐diabetic control (Con), diabetic control (DM), and diabetes with exercise (DM+Ex) groups. Diabetic groups were induced by the intravenous injection of streptozotocin. The DM+Ex group performed an 8‐week treadmill exercise program for 60 min/day, 5 day/week. At the end of experiments, the vasorelaxant responses to insulin, IGF‐1, acetylcholine (ACh), and sodium nitroprusside (SNP) were evaluated by the isometric tension of aortic rings in the organ baths. In addition, the roles of phosphatidylinositol 3‐kinase (PI3‐K) and nitric oxide synthase (NOS) in the vasorelaxation were examined by treating selective inhibitors. We found that 1) insulin‐, IGF‐1‐, and ACh‐induced vasorelaxant responses were significantly impaired in the DM group, compared with those in the Con group (
P
<0.05); 2) the exercise intervention significantly ameliorated the impaired vascular responses to insulin, IGF‐1, and ACh in the DM+Ex group, compared with those in the DM group (
P
<0.05); 3) these alternations of vascular responses affected by diabetes and exercise were mainly due to the release of PI3‐K and NOS; 4) no significant difference was found in SNP‐induced vasorelaxation among the three groups. Our results suggest that long‐term exercise intervention ameliorates vasorelaxation mediated by insulin and IGF‐1 in type 1 diabetic rats. The PI3K‐NOS‐dependent pathway is mainly involved in the exercise‐induced beneficial effects. This study was partly supported by the National Science Council, Taiwan (NSC95‐2314‐B‐006‐073‐MY2).
碩士
國立成功大學
物理治療研究所
96
Background and Purpose: Insulin and insulin-like growth factor-1 (IGF-1) have potent vasorelaxation effect via the production of endothelium-derived nitric oxide (EDNO). ...Accumulating evidences have indicated that both exercise training and insulin treatment improve vascular function by increasing EDNO bioavailability. However, few studies focus on the effects of these interventions on vascular responses mediated by insulin and IGF-1 in type 1 diabetic status. Therefore, the aim of the present study was to investigate the effects of long-term exercise training and insulin treatment on insulin- and IGF-1-mediated vascular function in type 1 diabetic status.
Methods: Male Wistar rats were randomly divided into the non-diabetic control (Con), the diabetic (DM), the diabetes with exercise training (DM+Ex), and the diabetes with insulin treatment (DM+IT) groups. Type 1 diabetes mellitus was induced by the intravenous injection of streptozotocin (65 mg/kg). The DM+Ex group performed an 8-week, moderate-intensity treadmill exercise program for 60 min/day, 5 day/week. The DM+IT group received a daily insulin treatment for 8 weeks with the gradually increased dose from 20 to 40 U/kg/day. At the end of experiments, the vasorelaxation responses to insulin, IGF-1, acetylcholine (ACh), and sodium nitroprusside (SNP) in thoracic aortas were evaluated among four groups. In addition, the roles of phosphatidylinositol 3-kinase (PI3-K) and endothelial NO synthase (eNOS) in the vasorelaxation responses were examined.
Results: We found that 1) insulin- and IGF-1-mediated vasorelaxation was significantly impaired in the DM group compared with that in the Con group (P<0.05); 2) both exercise training and insulin treatment significantly ameliorated these impaired vascular responses to insulin and IGF-1 in the DM+Ex and the DM+IT groups (P<0.05); 3) the alternations of vascular responses to insulin and IGF-1 were mainly due to the altered activities of PI3-K and eNOS; 4) consistent with previous studies, ACh-mediated vasorelaxation was impaired in the DM group, whereas exercise training and insulin treatment reversed the impaired vascular response in the DM+Ex and the DM+IT groups; 5) no significant difference was found in SNP-mediated vasorelaxation among four groups.
Conclusions: Our results indicated that insulin- and IGF-1-mediated vasorelaxation responses were impaired in type 1 diabetic status; whereas the exercise training and insulin treatment effectively reversed these vascular impairments. The benefits of both interventions were mainly due to the increased release of PI3-K and eNOS in the NO-dependent pathway.
Cingulin (CGN) is a pivotal cytoskeletal adaptor protein located at tight junctions. This study investigates the link between CGN mutation and increased cancer susceptibility through genetic and ...mechanistic analyses and proposes a potential targeted therapeutic approach.
In a high-cancer-density family without known pathogenic variants, we performed tumor-targeted and germline whole-genome sequencing to identify novel cancer-associated variants. Subsequently, these variants were validated in a 222 cancer patient cohort, and CGN c.3560C > T was identified as a potential cancer-risk allele. Both wild-type (WT) (c.3560C > C) and variant (c.3560C > T) were transfected into cancer cell lines and incorporated into orthotopic xenograft mice model for evaluating their effects on cancer progression. Western blot, immunofluorescence analysis, migration and invasion assays, two-dimensional gel electrophoresis with mass spectrometry, immunoprecipitation assays, and siRNA applications were used to explore the biological consequence of CGN c.3560C > T.
In cancer cell lines and orthotopic animal models, CGN c.3560C > T enhanced tumor progression with reduced sensitivity to oxaliplatin compared to the CGN WT. The variant induced downregulation of epithelial marker, upregulation of mesenchymal marker and transcription factor, which converged to initiate epithelial-mesenchymal transition (EMT). Proteomic analysis was conducted to investigate the elements driving EMT in CGN c.3560C > T. This exploration unveiled overexpression of IQGAP1 induced by the variant, contrasting the levels observed in CGN WT. Immunoprecipitation assay confirmed a direct interaction between CGN and IQGAP1. IQGAP1 functions as a regulator of multiple GTPases, particularly the Rho family. This overexpressed IQGAP1 was consistently associated with the activation of Rac1, as evidenced by the analysis of the cancer cell line and clinical sample harboring CGN c.3560C > T. Notably, activated Rac1 was suppressed following the downregulation of IQGAP1 by siRNA. Treatment with NSC23766, a selective inhibitor for Rac1-GEF interaction, resulted in the inactivation of Rac1. This intervention mitigated the EMT program in cancer cells carrying CGN c.3560C > T. Consistently, xenograft tumors with WT CGN showed no sensitivity to NSC23766 treatment, but NSC23766 demonstrated the capacity to attenuate tumor growth harboring c.3560C > T.
CGN c.3560C > T leads to IQGAP1 overexpression, subsequently triggering Rac1-dependent EMT. Targeting activated Rac1 is a strategy to impede the advancement of cancers carrying this specific variant.
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