scholarly journals Neuronal Lipoprotein Lipase Deficiency Alters Neuronal Function and Hepatic Metabolism

Metabolites ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 385
Author(s):  
Kimberley D. Bruce ◽  
Evgenia Dobrinskikh ◽  
Hong Wang ◽  
Ivan Rudenko ◽  
Hong Gao ◽  
...  
Keyword(s):  
Lipoprotein Lipase ◽  
Tca Cycle ◽  
Hepatic Metabolism ◽  
Molecular Characteristics ◽  
Fluorescence Lifetime Imaging ◽  
Alcoholic Fatty Liver ◽  
Hepatic Lipid Accumulation ◽  
Novel Target ◽  
And Function ◽  
Neuronal Physiology

The autonomic regulation of hepatic metabolism offers a novel target for the treatment of non-alcoholic fatty liver disease (NAFLD). However, the molecular characteristics of neurons that regulate the brain-liver axis remain unclear. Since mice lacking neuronal lipoprotein lipase (LPL) develop perturbations in neuronal lipid-sensing and systemic energy balance, we reasoned that LPL might be a component of pre-autonomic neurons involved in the regulation of hepatic metabolism. Here, we show that, despite obesity, mice with reduced neuronal LPL (NEXCreLPLflox (LPL KD)) show improved glucose tolerance and reduced hepatic lipid accumulation with aging compared to wilt type (WT) controls (LPLflox). To determine the effect of LPL deficiency on neuronal physiology, liver-related neurons were identified in the paraventricular nucleus (PVN) of the hypothalamus using the transsynaptic retrograde tracer PRV-152. Patch-clamp studies revealed reduced inhibitory post-synaptic currents in liver-related neurons of LPL KD mice. Fluorescence lifetime imaging microscopy (FLIM) was used to visualize metabolic changes in LPL-depleted neurons. Quantification of free vs. bound nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD) revealed increased glucose utilization and TCA cycle flux in LPL-depleted neurons compared to controls. Global metabolomics from hypothalamic cell lines either deficient in or over-expressing LPL recapitulated these findings. Our data suggest that LPL is a novel feature of liver-related preautonomic neurons in the PVN. Moreover, LPL loss is sufficient to cause changes in neuronal substrate utilization and function, which may precede changes in hepatic metabolism.

scholarly journals Neuronal Lipoprotein Lipase Deficiency Alters Neuronal Function and Hepatic Metabolism

2020 ◽  
Author(s):  
Kimberley D. Bruce ◽  
Hong Wang ◽  
Evgenia Dobrinskikh ◽  
Ivan Rudenko ◽  
Hong Gao ◽  
...  
Keyword(s):  
Lipoprotein Lipase ◽  
Tca Cycle ◽  
Hepatic Metabolism ◽  
Molecular Characteristics ◽  
Fluorescence Lifetime Imaging ◽  
Alcoholic Fatty Liver ◽  
Hepatic Lipid Accumulation ◽  
Novel Target ◽  
And Function ◽  
Neuronal Physiology

The autonomic regulation of hepatic metabolism offers a novel target for the treatment of non-alcoholic fatty liver disease (NAFLD). However, the molecular characteristics of neurons that regulate the brain-liver axis remain unclear. Since mice lacking neuronal lipoprotein lipase (LPL) develop perturbations in neuronal lipid-sensing and systemic energy balance, we reasoned that LPL might be a component of pre-autonomic neurons involved in the regulation of hepatic metabolism. Here we show that despite obesity, mice with reduced neuronal LPL (NEXCreLPLflox [LPL KD]) show improved glucose tolerance and reduced hepatic lipid accumulation with aging compared to WT controls (LPLflox). To determine the effect of LPL deficiency on neuronal physiology, liver-related neurons were identified in the paraventricular nucleus (PVN) of the hypothalamus using the transsynaptic retrograde tracer PRV-152. Patch-clamp studies revealed reduced inhibitory post-synaptic currents in liver-related neurons of LPL KD mice. Fluorescence Lifetime Imaging Microscopy (FLIM) was used to visualize metabolic changes in LPL-depleted neurons. Quantification of the free vs. bound Nicotinamide Adenine Dinucleotide (NADH) and Flavin Adenine Dinucleotide (FAD) revealed increased glucose utilization and TCA cycle flux in LPL-depleted neurons compared to controls. Global metabolomics from hypothalamic cell lines either deficient in, or over-expressing, LPL recapitulated these findings. Our data suggest that LPL is a novel feature of liver–related preautonomic neurons in the PVN. Moreover, LPL loss is sufficient to cause changes in neuronal substrate utilization and function, which may precede changes in hepatic metabolism.

Neuronal Lipoprotein Lipase Deficiency alters Neuronal Function and Hepatic Metabolism

2020 ◽  
Author(s):  
Kimberley Bruce ◽  
Hong Wang ◽  
Evgenia Dobrinskikh ◽  
Ivan A Rudenko ◽  
Hong Gao ◽  
...  
Keyword(s):  
Lipoprotein Lipase ◽  
Tca Cycle ◽  
Hepatic Metabolism ◽  
Hepatic Function ◽  
Molecular Characteristics ◽  
Fluorescence Lifetime Imaging ◽  
Alcoholic Fatty Liver ◽  
Hepatic Lipid Accumulation ◽  
Glucose And Lipid Metabolism ◽  
Neuronal Metabolism

Abstract Background: The autonomic regulation of hepatic metabolism offers a novel target for the treatment of non-alcoholic fatty liver disease (NAFLD). However, the molecular characteristics of neurons that regulate the brain-liver axis remain unclear. Since mice lacking neuronal lipoprotein lipase (LPL) develop perturbations in neuronal lipid-sensing and systemic energy balance, we reasoned that LPL may be a component of pre-autonomic neurons involved in the regulation of hepatic metabolism. Methods: Measures of glucose homeostasis in mice homozygous (NEXLPL-/-) and heterozygous (NEXLPL+/-) for neuronal LPL deficiency were compared to that of WT mice. A detailed analysis of hepatic glucose and lipid metabolism was also determined in NEXLPL+/- at 6-18 mo. To determine the effect of neuronal LPL deficiency on neuronal physiology, liver-related neurons were identified in the paraventricular nucleus (PVN) of the hypothalamus using the transsynaptic retrograde tracer PRV-152. In addition, we used Fluorescence Lifetime Imaging Microscopy (FLIM) as a novel method to visualize changes in neuronal metabolism following LPL-depletion directly in the PVN. Results: Here we show that despite obesity, mice with reduced neuronal LPL also show improved glucose tolerance and reduced hepatic lipid accumulation with aging, concomitant with reduced hepatic lipogenic gene expression (e.g. SCD1 and FADS2). Retroviral tracing and patch clamp studies revealed reduced inhibitory post-synaptic currents in liver-related neurons lacking LPL. Quantification of the free versus bound Nicotinamide Adenine Dinucleotide (NADH) and Flavin Adenine Dinucleotide (FAD), revealed that LPL loss resulted in altered substrate utilization characterized by increased glucose utilization and TCA cycle flux. These findings were recapitulated by analysis of global metabolites from hypothalamic cell lines either deficient in, or over-expressing, LPL. Conclusions: Our data suggest that LPL is a novel feature of liver–related preautonomic neurons in the PVN. Moreover, LPL loss is sufficient to alter neuronal metabolism and function, leading to changes in systemic glucose metabolism including improved hepatic function with age.

Structure and Function of Proprotein Convertase Subtilisin/kexin Type 9 (PCSK9) in Hyperlipidemia and Atherosclerosis

2019 ◽  
Vol 20 (10) ◽  
pp. 1029-1040 ◽  
Author(s):  
Xinjie Lu
Keyword(s):  
Low Density Lipoprotein ◽  
Ldl Receptor ◽  
Density Lipoprotein ◽  
Structure And Function ◽  
Lipid Lowering ◽  
Lipid Lowering Therapy ◽  
Proprotein Convertase ◽  
Novel Target ◽  
New Treatments ◽  
And Function

Background:One of the important factors in Low-Density Lipoprotein (LDL) metabolism is the LDL receptor (LDLR) by its capacity to bind and subsequently clear cholesterol derived from LDL (LDL-C) in the circulation. Proprotein Convertase Subtilisin-like Kexin type 9 (PCSK9) is a newly discovered serine protease that destroys LDLR in the liver and thereby controls the levels of LDL in plasma. Inhibition of PCSK9-mediated degradation of LDLR has, therefore, become a novel target for lipid-lowering therapy.Methods:We review the current understanding of the structure and function of PCSK9 as well as its implications for the treatment of hyperlipidemia and atherosclerosis.Results:New treatments such as monoclonal antibodies against PCSK9 may be useful agents to lower plasma levels of LDL and hence prevent atherosclerosis.Conclusion:PCSK9's mechanism of action is not yet fully clarified. However, treatments that target PCSK9 have shown striking early efficacy and promise to improve the lives of countless patients with hyperlipidemia and atherosclerosis.

scholarly journals Brain Long Noncoding RNAs: Multitask Regulators of Neuronal Differentiation and Function

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3951
Author(s):  
Sarva Keihani ◽  
Verena Kluever ◽  
Eugenio F. Fornasiero
Keyword(s):  
Neuronal Differentiation ◽  
Neuronal Excitability ◽  
Noncoding Rnas ◽  
Long Noncoding Rnas ◽  
Regulatory Mechanisms ◽  
Control Robustness ◽  
Living Organisms ◽  
And Function ◽  
Regulatory Functions ◽  
Neuronal Physiology

The extraordinary cellular diversity and the complex connections established within different cells types render the nervous system of vertebrates one of the most sophisticated tissues found in living organisms. Such complexity is ensured by numerous regulatory mechanisms that provide tight spatiotemporal control, robustness and reliability. While the unusual abundance of long noncoding RNAs (lncRNAs) in nervous tissues was traditionally puzzling, it is becoming clear that these molecules have genuine regulatory functions in the brain and they are essential for neuronal physiology. The canonical view of RNA as predominantly a ‘coding molecule’ has been largely surpassed, together with the conception that lncRNAs only represent ‘waste material’ produced by cells as a side effect of pervasive transcription. Here we review a growing body of evidence showing that lncRNAs play key roles in several regulatory mechanisms of neurons and other brain cells. In particular, neuronal lncRNAs are crucial for orchestrating neurogenesis, for tuning neuronal differentiation and for the exact calibration of neuronal excitability. Moreover, their diversity and the association to neurodegenerative diseases render them particularly interesting as putative biomarkers for brain disease. Overall, we foresee that in the future a more systematic scrutiny of lncRNA functions will be instrumental for an exhaustive understanding of neuronal pathophysiology.

Dietary raffinose ameliorates hepatic lipid accumulation induced by cholic acid via modulation of enterohepatic bile acid circulation in rats

2021 ◽  
pp. 1-26
Author(s):  
Kenta Maegawa ◽  
Haruka Koyama ◽  
Satoru Fukiya ◽  
Atsushi Yokota ◽  
Koichiro Ueda ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Bile Acid ◽  
Cholic Acid ◽  
Lipid Accumulation ◽  
Enterohepatic Circulation ◽  
Control Diet ◽  
Hepatic Triglyceride ◽  
Alcoholic Fatty Liver ◽  
Hepatic Lipid ◽  
Hepatic Lipid Accumulation

Abstract Enterohepatic circulation of 12α-hydroxylated (12αOH) bile acid (BA) is enhanced depending on the energy intake in high-fat diet-fed rats. Such BA metabolism can be reproduced using a diet supplemented with cholic acid (CA), which also induces simple steatosis, without inflammation and fibrosis, accompanied by some other symptoms that are frequently observed in the condition of non-alcoholic fatty liver in rats. We investigated whether supplementation of the diet with raffinose (Raf) improves hepatic lipid accumulation induced by the CA-fed condition in rats. After acclimation to the AIN-93-based control diet, male Wistar rats were fed diets supplemented with a combination of Raf (30 g/kg diet) and/or CA (0.5 g/kg diet) for 4 weeks. Dietary Raf normalised hepatic triglyceride levels (two-way ANOVA P<0.001 for CA, P=0.02 for Raf, and P=0.004 for interaction) in the CA-supplemented diet-fed rats. Dietary Raf supplementation reduced hepatic 12αOH BA concentration (two-way ANOVA P<0.001 for CA, P=0.003 for Raf, and P=0.03 for interaction). The concentration of 12αOH BA was reduced in the aortic and portal plasma. Raf supplementation increased acetic acid concentration in the caecal contents (two-way ANOVA P=0.001 as a main effect). Multiple regression analysis revealed that concentrations of aortic 12αOH BA and caecal acetic acid could serve as predictors of hepatic triglyceride concentration (R2=0.55, P<0.001). However, Raf did not decrease the secondary 12αOH BA concentration in the caecal contents as well as the transaminase activity in the CA diet-fed rats. These results imply that dietary Raf normalises hepatic lipid accumulation via suppression of enterohepatic 12αOH BA circulation.

Mesencephalic GABA neuronal development: no more on the other side of oblivion

2014 ◽  
Vol 5 (5) ◽  
pp. 371-382 ◽  
Author(s):  
Suyan Li ◽  
Sampada Joshee ◽  
Anju Vasudevan
Keyword(s):  
Transcriptional Control ◽  
Neuronal Development ◽  
Developmental Regulation ◽  
Molecular Characteristics ◽  
Psychiatric Illnesses ◽  
Neuronal Populations ◽  
Gaba Neurons ◽  
Recent Developments ◽  
And Function ◽  
The Brain

AbstractMidbrain GABA neurons, endowed with multiple morphological, physiological and molecular characteristics as well as projection patterns are key players interacting with diverse regions of the brain and capable of modulating several aspects of behavior. The diversity of these GABA neuronal populations based on their location and function in the dorsal, medial or ventral midbrain has challenged efforts to rapidly uncover their developmental regulation. Here we review recent developments that are beginning to illuminate transcriptional control of GABA neurons in the embryonic midbrain (mesencephalon) and discuss its implications for understanding and treatment of neurological and psychiatric illnesses.

scholarly journals Pseudogene ACTBP2 increases blood–brain barrier permeability by promoting KHDRBS2 transcription through recruitment of KMT2D/WDR5 in Aβ1–42 microenvironment

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Qianshuo Liu ◽  
Xiaobai Liu ◽  
Defeng Zhao ◽  
Xuelei Ruan ◽  
Rui Su ◽  
...  
Keyword(s):  
Blood Brain Barrier ◽  
Molecular Mechanisms ◽  
Rna Binding ◽  
Vital Role ◽  
Brain Barrier ◽  
Blood Brain ◽  
Bbb Permeability ◽  
Novel Target ◽  
And Function

AbstractThe blood–brain barrier (BBB) has a vital role in maintaining the homeostasis of the central nervous system (CNS). Changes in the structure and function of BBB can accelerate Alzheimer’s disease (AD) development. β-Amyloid (Aβ) deposition is the major pathological event of AD. We elucidated the function and possible molecular mechanisms of the effect of pseudogene ACTBP2 on the permeability of BBB in Aβ1–42 microenvironment. BBB model treated with Aβ1–42 for 48 h were used to simulate Aβ-mediated BBB dysfunction in AD. We proved that pseudogene ACTBP2, RNA-binding protein KHDRBS2, and transcription factor HEY2 are highly expressed in ECs that were obtained in a BBB model in vitro in Aβ1–42 microenvironment. In Aβ1–42-incubated ECs, ACTBP2 recruits methyltransferases KMT2D and WDR5, binds to KHDRBS2 promoter, and promotes KHDRBS2 transcription. The interaction of KHDRBS2 with the 3′UTR of HEY2 mRNA increases the stability of HEY2 and promotes its expression. HEY2 increases BBB permeability in Aβ1–42 microenvironment by transcriptionally inhibiting the expression of ZO-1, occludin, and claudin-5. We confirmed that knocking down of Khdrbs2 or Hey2 increased the expression levels of ZO-1, occludin, and claudin-5 in APP/PS1 mice brain microvessels. ACTBP2/KHDRBS2/HEY2 axis has a crucial role in the regulation of BBB permeability in Aβ1–42 microenvironment, which may provide a novel target for the therapy of AD.

scholarly journals Expression and function of the novel proto-oncogene PBF in thyroid cancer: a new target for augmenting radioiodine uptake

2011 ◽  
Vol 210 (2) ◽  
pp. 157-163 ◽  
Author(s):  
Vicki E Smith ◽  
Jayne A Franklyn ◽  
Christopher J McCabe
Keyword(s):  
Thyroid Cancer ◽  
Current Data ◽  
Subcellular Localisation ◽  
Sodium Iodide Symporter ◽  
Iodide Uptake ◽  
Radioiodine Uptake ◽  
Novel Target ◽  
And Function

Pituitary tumor-transforming gene (PTTG)-binding factor (PBF; PTTG1IP) was initially identified through its interaction with the human securin, PTTG. Like PTTG, PBF is upregulated in multiple endocrine tumours including thyroid cancer. PBF is believed to induce the translocation of PTTG into the cell nucleus where it can drive tumourigenesis via a number of different mechanisms. However, an independent transforming ability has been demonstrated both in vitro and in vivo, suggesting that PBF is itself a proto-oncogene. Studied in only a limited number of publications to date, PBF is emerging as a protein with a growing repertoire of roles. Recent data suggest that PBF possesses a complex multifunctionality in an increasing number of tumour settings. For example, PBF is upregulated by oestrogen and mediates oestrogen-stimulated cell invasion in breast cancer cells. In addition to a possible role in the induction of thyroid tumourigenesis, PBF overexpression in thyroid cancers inhibits iodide uptake. PBF has been shown to repress sodium iodide symporter (NIS) activity by transcriptional regulation of NIS expression through the human NIS upstream enhancer and further inhibits iodide uptake via a post-translational mechanism of NIS governing subcellular localisation. This review discusses the current data describing PBF expression and function in thyroid cancer and highlights PBF as a novel target for improving radioiodine uptake and thus prognosis in thyroid cancer.

Abstract 217: Quaking Post-Transcriptionally Guides Monocyte Adhesion and Differentiation into the Pro-Inflammatory Macrophage

2015 ◽  
Vol 35 (suppl_1) ◽  
Author(s):  
Ruben G de Bruin ◽  
Lily Shiue ◽  
Anjana Djarmshi ◽  
Hetty C de Boer ◽  
Wai Yi Leung ◽  
...  
Keyword(s):  
Transcriptional Control ◽  
Rna Binding ◽  
Inflammatory Diseases ◽  
Human Monocyte ◽  
Human Macrophage ◽  
Monocyte Adhesion ◽  
Sequence Elements ◽  
Bound Sequence ◽  
Novel Target ◽  
And Function

A hallmark of inflammatory diseases is the excessive recruitment and influx of monocytes to sites of tissue damage and their ensuing differentiation into macrophages. Numerous stimuli are known to induce new transcription necessary for macrophage identity, but post-transcriptional control of human macrophage differentiation is less well understood. Here, we detail our discovery that levels of the RNA-binding protein Quaking (QKI) are low in monocytes of early atherosclerotic lesions, but abundant in macrophages of advanced plaques. Specific depletion of QKI protein impaired monocyte adhesion, migration and differentiation into macrophages, and lesion formation. RNA-seq and microarray analysis of human monocyte and macrophage transcriptomes, including those of a unique QKI haploinsufficient patient, reveal developmental changes in RNA levels and alternative splicing of RNA transcripts enriched in QKI-bound sequence elements. The importance of these transcripts and requirement for QKI during differentiation illustrates a central role for QKI in post-transcriptionally guiding macrophage identity and function. These studies implicate QKI as a novel target for therapeutic intervention in inflammatory diseases.

scholarly journals N-Acetyl Cysteine Targets Hepatic Lipid Accumulation to Curb Oxidative Stress and Inflammation in NAFLD: A Comprehensive Analysis of the Literature

Antioxidants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1283
Author(s):  
Phiwayinkosi V. Dludla ◽  
Bongani B. Nkambule ◽  
Sithandiwe E. Mazibuko-Mbeje ◽  
Tawanda M. Nyambuya ◽  
Fabio Marcheggiani ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Lipid Accumulation ◽  
Randomized Clinical Trials ◽  
Therapeutic Potential ◽  
Therapeutic Effects ◽  
Metabolic Complications ◽  
Alcoholic Fatty Liver ◽  
Hepatic Lipid ◽  
Hepatic Lipid Accumulation ◽  
Acetyl Cysteine

Impaired adipose tissue function and insulin resistance remain instrumental in promoting hepatic lipid accumulation in conditions of metabolic syndrome. In fact, enhanced lipid accumulation together with oxidative stress and an abnormal inflammatory response underpin the development and severity of non-alcoholic fatty liver disease (NAFLD). There are currently no specific protective drugs against NAFLD, and effective interventions involving regular exercise and healthy diets have proved difficult to achieve and maintain. Alternatively, due to its antioxidant and anti-inflammatory properties, there has been growing interest in understanding the therapeutic effects of N-acetyl cysteine (NAC) against metabolic complications, including NAFLD. Here, reviewed evidence suggests that NAC blocks hepatic lipid accumulation in preclinical models of NAFLD. This is in part through the effective regulation of a fatty acid scavenger molecule (CD36) and transcriptional factors such as sterol regulatory element-binding protein (SREBP)-1c/-2 and peroxisome proliferator-activated receptor gamma (PPARγ). Importantly, NAC appears effective in improving liver function by reducing pro-inflammatory markers such as interleukin (IL)-6 IL-1β, tumour necrosis factor alpha (TNF-α) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). This was primarily through the attenuation of lipid peroxidation and enhancements in intracellular response antioxidants, particularly glutathione. Very few clinical studies support the beneficial effects of NAC against NAFLD-related complications, thus well-organized randomized clinical trials are still necessary to confirm its therapeutic potential.

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