Niemann-Pick C1-deficient mice lacking sterol O-acyltransferase 2 have less hepatic cholesterol entrapment and improved liver function

Cholesteryl esters are generated at multiple sites in the body by sterol O-acyltransferase (SOAT) 1 or SOAT2 in various cell types and lecithin cholesterol acyltransferase in plasma. Esterified cholesterol and triacylglycerol contained in lipoproteins cleared from the circulation via receptor-mediated or bulk-phase endocytosis are hydrolyzed by lysosomal acid lipase within the late endosomal/lysosomal (E/L) compartment. Then, through the successive actions of Niemann-Pick C (NPC) 2 and NPC 1, unesterified cholesterol (UC) is exported from the E/L compartment to the cytosol. Mutations in either NPC1 or NPC2 lead to continuing entrapment of UC in all organs, resulting in multisystem disease, which includes hepatic dysfunction and in some cases liver failure. These studies investigated primarily whether elimination of SOAT2 in NPC1-deficient mice impacted hepatic UC sequestration, inflammation, and transaminase activities. Measurements were made in 7-wk-old mice fed a low-cholesterol chow diet or one enriched with cholesterol starting 2 wk before study. In the chow-fed mice, NPC1:SOAT2 double knockouts, compared with their littermates lacking only NPC1, had 20% less liver mass, 28% lower hepatic UC concentrations, and plasma alanine aminotransferase and aspartate aminotransferase activities that were decreased by 48% and 36%, respectively. mRNA expression levels for several markers of inflammation were all significantly lower in the NPC1 mutants lacking SOAT2. The existence of a new class of potent and selective SOAT2 inhibitors provides an opportunity for exploring if suppression of this enzyme could potentially become an adjunctive therapy for liver disease in NPC1 deficiency. NEW & NOTEWORTHY In Niemann-Pick type C1 (NPC1) disease, the entrapment of unesterified cholesterol (UC) in the endosomal/lysosomal compartment of all cells causes multiorgan disease, including neurodegeneration, pulmonary dysfunction, and liver failure. Some of this sequestered UC entered cells initially in the esterified form. When sterol O-acyltransferase 2, a cholesterol esterifying enzyme present in enterocytes and hepatocytes, is eliminated in NPC1-deficient mice, there is a reduction in their hepatomegaly, hepatic UC content, and cellular injury.

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Multiple mechanisms limit the accumulation of unesterified cholesterol in the small intestine of mice deficient in both ACAT2 and ABCA1

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.00190.2010 ◽

2010 ◽

Vol 299 (5) ◽

pp. G1012-G1022 ◽

Cited By ~ 25

Author(s):

Stephen D. Turley ◽

Mark A. Valasek ◽

Joyce J. Repa ◽

John M. Dietschy

Keyword(s):

Small Intestine ◽

Mrna Level ◽

Cholesterol Absorption ◽

Cholesterol Homeostasis ◽

High Cholesterol Diet ◽

Unesterified Cholesterol ◽

Compensatory Mechanisms ◽

Niemann Pick ◽

Sterol Excretion ◽

Deficient Mice

Cholesterol homeostasis in the enterocyte is regulated by the interplay of multiple genes that ultimately determines the net amount of cholesterol reaching the circulation from the small intestine. The effect of deleting these genes, particularly acyl CoA:cholesterol acyl transferase 2 (ACAT2), on cholesterol absorption and fecal sterol excretion is well documented. We also know that the intestinal mRNA level for adenosine triphosphate-binding cassette transporter A1 (ABCA1) increases in Acat2−/− mice. However, none of these studies has specifically addressed how ACAT2 deficiency impacts the relative proportions of esterified and unesterified cholesterol (UC) in the enterocyte and whether the concurrent loss of ABCA1 might result in a marked buildup of UC. Therefore, the present studies measured the expression of numerous genes and related metabolic parameters in the intestine and liver of ACAT2-deficient mice fed diets containing either added cholesterol or ezetimibe, a selective sterol absorption inhibitor. Cholesterol feeding raised the concentration of UC in the small intestine, and this was accompanied by a significant reduction in the relative mRNA level for Niemann-Pick C1-like 1 (NPC1L1) and an increase in the mRNA level for both ABCA1 and ABCG5/8. All these changes were reversed by ezetimibe. When mice deficient in both ACAT2 and ABCA1 were fed a high-cholesterol diet, the increase in intestinal UC levels was no greater than it was in mice lacking only ACAT2. This resulted from a combination of compensatory mechanisms including diminished NPC1L1-mediated cholesterol uptake, increased cholesterol efflux via ABCG5/8, and possibly rapid cell turnover.

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Potential Diagnostic and Prognostic Biomarkers of Epigenetic Drift within the Cardiovascular Compartment

BioMed Research International ◽

10.1155/2016/2465763 ◽

2016 ◽

Vol 2016 ◽

pp. 1-10 ◽

Cited By ~ 7

Author(s):

Robert G. Wallace ◽

Laura C. Twomey ◽

Marc-Antoine Custaud ◽

Niall Moyna ◽

Philip M. Cummins ◽

...

Keyword(s):

Biological Fluids ◽

Cell Types ◽

Lifestyle Changes ◽

The Body ◽

Direct Function ◽

Disease States ◽

Markers Of Inflammation ◽

Wide Range ◽

Alternative Means ◽

New Biomarkers

Biomarkers encompass a wide range of different measurable indicators, representing a tangible link to physiological changes occurring within the body. Accessibility, sensitivity, and specificity are significant factors in biomarker suitability. New biomarkers continue to be discovered, and questions over appropriate selection and assessment of their usefulness remain. If traditional markers of inflammation are not sufficiently robust in their specificity, then perhaps alternative means of detection may provide more information. Epigenetic drift (epigenetic modifications as they occur as a direct function with age), and its ancillary elements, including platelets, secreted microvesicles (MVs), and microRNA (miRNA), may hold enormous predictive potential. The majority of epigenetic drift observed in blood is independent of variations in blood cell composition, addressing concerns affecting traditional blood-based biomarker efficacy. MVs are found in plasma and other biological fluids in healthy individuals. Altered MV/miRNA profiles may also be found in individuals with various diseases. Platelets are also highly reflective of physiological and lifestyle changes, making them extremely sensitive biomarkers of human health. Platelets release increased levels of MVs in response to various stimuli and under a plethora of disease states, which demonstrate a functional effect on other cell types.

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Endogenous Expression of Functional Factor VIII by Human Mesenchymal Stem Cells In Culture

Blood ◽

10.1182/blood.v116.21.2216.2216 ◽

2010 ◽

Vol 116 (21) ◽

pp. 2216-2216

Author(s):

Chad Sanada ◽

Evan J Colletti ◽

Melisa Soland ◽

Chung-Jung Kuo ◽

Christopher D Porada ◽

...

Keyword(s):

Stem Cells ◽

Mesenchymal Stem Cells ◽

Liver Failure ◽

Cell Types ◽

The Body ◽

Rt Pcr ◽

Fviii Activity ◽

Innate Ability

Abstract Abstract 2216 The liver is considered to be the primary site of factor VIII (FVIII) production in the body; however, evidence is mounting that suggests there are secondary sites in which considerable synthesis of FVIII takes place. Studies of FVIII mRNA expression in various human tissues have revealed that FVIII message can be found throughout the body. Additionally, acute liver failure correlates with an increase in circulating FVIII levels. Some reports have identified endothelial cells as a significant extra-hepatic source of FVIII, possibly explaining both the widespread presence of FVIII mRNA and the increase in FVIII levels upon liver failure. However, the possibility exists that other cell types present throughout the body also produce FVIII and contribute to circulating FVIII levels. Mesenchymal Stem Cells (MSCs) represent a potential alternative; they are a diverse group of stromal cells which can be found in the perivascular regions of multiple tissues throughout the body. Previous studies demonstrated that MSCs are capable of efficiently producing and secreting high levels of FVIII in vitro when transduced with FVIII-encoding viral vectors, but to date, the innate ability of MSCs to produce FVIII has not been explored. As such, we investigated the potential for MSCs to produce endogenous FVIII message and secrete functional protein. MSCs isolated based on Stro-1 positivity from human lung, liver, brain, and bone marrow (BM) were grown in cell culture and assayed for production of FVIII message by both microarray analysis and RT-PCR. Microarray data showed that there were significant amounts of FVIII message in all four cell types tested and that the amount of message in BM MSCs was three-fold higher than each of the other three cell types. RT-PCR analysis confirmed the presence of FVIII message in all four MSC populations. Secretion of functional FVIII protein was subsequently measured using a chromogenic assay. MSC culture supernatants were collected for either 24 or 48 hours, and FVIII activity was determined using pooled normal human plasma as a control to create a standard curve. FVIII activity in the supernatants of MSCs was in the range of 0.6 to 2.0 mU/1×10^6 cells/ 24hr. Moreover, MSCs continued to express and produce FVIII during time in culture until our last evaluation at passage 20, indicating that there is an innate ability of these cells to continually produce FVIII. Taken together, these data demonstrate that human MSCs are capable of producing and secreting functional FVIII in vitro, and given their widespread location throughout the body, this finding raises the possibility that, in vivo, these cells might significantly contribute to the total FVIII pool. This is the first report, to our knowledge, that implicates MSCs as a potential endogenous source for circulating FVIII. Further studies of in vivo FVIII expression by MSCs are warranted and may provide a clearer understanding of extra-hepatic FVIII production in the body while aiding in the discovery of novel therapies for hemophilia A. Disclosures: No relevant conflicts of interest to declare.

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Effect of Dapagliflozin on Intestinal Flora in MafA-deficient Mice

Current Pharmaceutical Design ◽

10.2174/1381612824666180912143434 ◽

2018 ◽

Vol 24 (27) ◽

pp. 3223-3231 ◽

Cited By ~ 3

Author(s):

Luyao Li ◽

Shiyao Xu ◽

Tingting Guo ◽

Shouliang Gong ◽

Chuan Zhang

Keyword(s):

Blood Glucose ◽

High Throughput Sequencing ◽

Fatty Acid Content ◽

Fasting Blood Glucose ◽

Intestinal Flora ◽

Short Chain Fatty Acids ◽

The Body ◽

Short Chain ◽

Control Group ◽

Deficient Mice

Objective: To investigate the effect of dapagliflozin on intestinal microflora in MafA-deficient mice using an animal model of diabetes. Methods: Male MafA-deficient mice were administered dapagliflozin (1.0 mg/kg/d) intragastrically for 6 weeks. Mouse body weights and fasting blood glucose levels were measured, and intestinal short-chain fatty acids were measured by gas chromatography. A series of methods was used to analyse the number of primary harmful bacteria in the faeces, and high-throughput sequencing was used to sequence the changes in intestinal flora. Results: The weight of the mice decreased after dapagliflozin gavage, and fasting blood glucose was significantly lower than that in the control group (P < 0.001). Acetic acid and butyric acid contents in the intestinal tracts of the mice increased, and the growth of harmful microorganisms, such as Clostridium perfringens, enterococci, Enterobacteriaceae, and intestinal enterococci, was inhibited. Blautia is a species found in the experimental group and was significantly different from the control and blank groups as determined by the LDA score from highthroughput sequencing. Conclusion: Dapagliflozin can reduce fasting blood glucose, decrease body weight, increase short-chain fatty acid content, regulate the intestinal microecological balance of the body and promote blood glucose and energy homeostasis.

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Predictive Markers of Early Cardiovascular Impairment and Insulin Resistance in Obese Pediatric Patients

Diagnostics ◽

10.3390/diagnostics11040735 ◽

2021 ◽

Vol 11 (4) ◽

pp. 735

Author(s):

Laura Mihaela Trandafir ◽

Elena Cojocaru ◽

Mihaela Moscalu ◽

Maria Magdalena Leon Constantin ◽

Ingrith Miron ◽

...

Keyword(s):

Insulin Resistance ◽

Plasma Cortisol ◽

Predictive Power ◽

Pediatric Patients ◽

The Body ◽

Control Group ◽

Homa Index ◽

Obese Patients ◽

Metabolic Markers ◽

Markers Of Inflammation

Background: The increased prevalence of obesity among children determined the rising number of its comorbidities in children and adults, too. This study aimed to evaluate certain markers of inflammation and insulin resistance in obese pediatric patients, identifying those who are more likely to develop further complications. Methods: We included 115 obese pediatric patients: 85 overweight and obese patients in the study group and 30 normal-weight patients in the control group. We calculated the body mass index (BMI) and we evaluated markers (biological, inflammatory) and the hormones profile. Results: Low-threshold inflammation was assessed by measuring interleukin 6 IL-6 and Intercellular Adhesion Molecules (ICAM). The analysis showed that IL-6 is significantly correlated with glucose (p = 0.001) and BMI value (p = 0.031). ICAM correlates significantly with triglycerides (p = 0.001), glucose (p = 0.044) and BMI percentile (p = 0.037). For pediatric obese patients, endotoxemia has been significantly correlated only with BMI percentile (p = 0.001). Plasma cortisol did not show significant correlations with total cholesterol, triglycerides, glucose or BMI percentile. The results indicated a significant predictive power of BMI percentile on inflammatory markers: IL-6 (AUC = 0.803, p < 0.001), ICAM (AUC = 0.806, p < 0.001) and endotoxemia (AUC = 0.762, p = 0.019). Additionally, BMI percentile has a significant predictive power for metabolic markers of insulin resistance (insulin value: AUC = 0.72, p < 0.001 and HOMA index: AUC = 0.68, p = 0.003). Conclusions: The study highlighted the importance of early markers of cardiovascular risk in obese pediatric patients represented by IL-6, ICAM, endotoxemia and their correlation with metabolic markers of insulin resistance represented by insulinemia, HOMA index and plasma cortisol. It can clearly be considered that the BMI percentile has significant predictive power for metabolic markers of insulin resistance.

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Extracellular-Vesicle-Based Coatings Enhance Bioactivity of Titanium Implants—SurfEV

Nanomaterials ◽

10.3390/nano11061445 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1445

Author(s):

Taisa Nogueira Pansani ◽

Thanh Huyen Phan ◽

Qingyu Lei ◽

Alexey Kondyurin ◽

Bill Kalionis ◽

...

Keyword(s):

Cell Proliferation ◽

Titanium Surface ◽

Wound Closure ◽

Cell Types ◽

Extracellular Vesicle ◽

Tissue Growth ◽

Titanium Implants ◽

The Body ◽

High Concentrations ◽

And Migration

Extracellular vesicles (EVs) are nanoparticles released by cells that contain a multitude of biomolecules, which act synergistically to signal multiple cell types. EVs are ideal candidates for promoting tissue growth and regeneration. The tissue regenerative potential of EVs raises the tantalizing possibility that immobilizing EVs on implant surfaces could potentially generate highly bioactive and cell-instructive surfaces that would enhance implant integration into the body. Such surfaces could address a critical limitation of current implants, which do not promote bone tissue formation or bond bone. Here, we developed bioactive titanium surface coatings (SurfEV) using two types of EVs: secreted by decidual mesenchymal stem cells (DEVs) and isolated from fermented papaya fluid (PEVs). For each EV type, we determined the size, morphology, and molecular composition. High concentrations of DEVs enhanced cell proliferation, wound closure, and migration distance of osteoblasts. In contrast, the cell proliferation and wound closure decreased with increasing concentration of PEVs. DEVs enhanced Ca/P deposition on the titanium surface, which suggests improvement in bone bonding ability of the implant (i.e., osteointegration). EVs also increased production of Ca and P by osteoblasts and promoted the deposition of mineral phase, which suggests EVs play key roles in cell mineralization. We also found that DEVs stimulated the secretion of secondary EVs observed by the presence of protruding structures on the cell membrane. We concluded that, by functionalizing implant surfaces with specialized EVs, we will be able to enhance implant osteointegration by improving hydroxyapatite formation directly at the surface and potentially circumvent aseptic loosening of implants.

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High-throughput screening of circRNAs reveals novel mechanisms of tuberous sclerosis complex-related renal angiomyolipoma

Human Genomics ◽

10.1186/s40246-021-00344-1 ◽

2021 ◽

Vol 15 (1) ◽

Author(s):

Yang Zhao ◽

Hao Guo ◽

Wenda Wang ◽

Guoyang Zheng ◽

Zhan Wang ◽

...

Keyword(s):

Lipid Metabolism ◽

Tuberous Sclerosis ◽

Tuberous Sclerosis Complex ◽

Regulatory Network ◽

High Throughput Screening ◽

Kidney Tissue ◽

Cell Types ◽

The Body ◽

Differentially Expressed ◽

Renal Angiomyolipoma

Abstract Objective Tuberous sclerosis complex (TSC) is a rare autosomal dominant disease characterized by lesions throughout the body. Our previous study showed the abnormal up-regulation of miRNAs plays an important part in the pathogenesis of TSC-related renal angiomyolipoma (TSC-RAML). circRNAs were known as important regulators of miRNA, but little is known about the circRNAs in TSC-RAMLs. Methods Microarray chips and RNA sequencing were used to identify the circRNAs and mRNAs that were differently expressed between the TSC-RAML and normal kidney tissue. A competitive endogenous RNA (ceRNA) regulatory network was constructed to reveal the regulation of miRNAs and mRNAs by the circRNAs. The biological functions of circRNA and mRNA were analyzed by pathway analysis. Microenvironmental cell types were estimated with the MCP-counter package. Results We identified 491 differentially expressed circRNAs (DECs) and 212 differentially expressed genes (DEGs), and 6 DECs were further confirmed by q-PCR. A ceRNA regulatory network which included 6 DECs, 5 miRNAs, and 63 mRNAs was established. Lipid biosynthetic process was significantly up-regulated in TSC-RAML, and the humoral immune response and the leukocyte chemotaxis pathway were found to be down-regulated. Fibroblasts are enriched in TSC-RAML, and the up-regulation of circRNA_000799 and circRNA_025332 may be significantly correlated to the infiltration of the fibroblasts. Conclusion circRNAs may regulate the lipid metabolism of TSC-RAML by regulation of the miRNAs. Fibroblasts are enriched in TSC-RAMLs, and the population of fibroblast may be related to the alteration of circRNAs of TSC-RAML. Lipid metabolism in fibroblasts is a potential treatment target for TSC-RAML.

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Glucocorticoid Receptor β (GRβ): Beyond Its Dominant-Negative Function

International Journal of Molecular Sciences ◽

10.3390/ijms22073649 ◽

2021 ◽

Vol 22 (7) ◽

pp. 3649

Author(s):

Patricia Ramos-Ramírez ◽

Omar Tliba

Keyword(s):

Current Knowledge ◽

Inflammatory Diseases ◽

Cell Communication ◽

Cell Types ◽

The Body ◽

Dominant Negative ◽

Negative Effects ◽

Independent Manner ◽

Distinct Cell ◽

Induced Apoptosis

Glucocorticoids (GCs) act via the GC receptor (GR), a receptor ubiquitously expressed in the body where it drives a broad spectrum of responses within distinct cell types and tissues, which vary in strength and specificity. The variability of GR-mediated cell responses is further extended by the existence of GR isoforms, such as GRα and GRβ, generated through alternative splicing mechanisms. While GRα is the classic receptor responsible for GC actions, GRβ has been implicated in the impairment of GRα-mediated activities. Interestingly, in contrast to the popular belief that GRβ actions are restricted to its dominant-negative effects on GRα-mediated responses, GRβ has been shown to have intrinsic activities and “directly” regulates a plethora of genes related to inflammatory process, cell communication, migration, and malignancy, each in a GRα-independent manner. Furthermore, GRβ has been associated with increased cell migration, growth, and reduced sensitivity to GC-induced apoptosis. We will summarize the current knowledge of GRβ-mediated responses, with a focus on the GRα-independent/intrinsic effects of GRβ and the associated non-canonical signaling pathways. Where appropriate, potential links to airway inflammatory diseases will be highlighted.

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Haemolysis, elevated liver enzymes and low platelets: Diagnosis and management in critical care

Journal of the Intensive Care Society ◽

10.1177/17511437211025410 ◽

2021 ◽

pp. 175114372110254

Author(s):

Evangelia Poimenidi ◽

Yavor Metodiev ◽

Natasha Nicole Archer ◽

Richard Jackson ◽

Mansoor Nawaz Bangash ◽

...

Keyword(s):

Acute Kidney Injury ◽

Critical Care ◽

Liver Failure ◽

Hellp Syndrome ◽

Seizure Control ◽

Liver Enzymes ◽

Kidney Injury ◽

Definitive Treatment ◽

Multisystem Disease ◽

Elevated Liver Enzymes

A thirty-year-old pregnant woman was admitted to hospital with headache and gastrointestinal discomfort. She developed peripheral oedema and had an emergency caesarean section following an episode of tonic-clonic seizures. Her delivery was further complicated by postpartum haemorrhage and she was admitted to the Intensive Care Unit (ICU) for further resuscitation and seizure control which required infusions of magnesium and multiple anticonvulsants. Despite haemodynamic optimisation she developed an acute kidney injury with evidence of liver damage, thrombocytopenia and haemolysis. Haemolysis, Elevated Liver enzymes and Low Platelets (HELLP) syndrome, a multisystem disease of advanced pregnancy which overlaps with pre-eclampsia, was diagnosed. HELLP syndrome is associated with a range of complications which may require critical care support, including placental abruption and foetal loss, acute kidney injury, microangiopathic haemolytic anaemia, acute liver failure and liver capsule rupture. Definitive treatment of HELLP is delivery of the fetus and in its most severe forms requires admission to the ICU for multiorgan support. Therapeutic strategies in ICU are mainly supportive and include blood pressure control, meticulous fluid balance and possibly escalation to renal replacement therapy, mechanical ventilation, neuroprotection, seizure control, and management of liver failure-related complications. Multidisciplinary input is essential for optimal treatment.

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Estrogens Protect against High-Fat Diet-Induced Insulin Resistance and Glucose Intolerance in Mice

Endocrinology ◽

10.1210/en.2008-0971 ◽

2009 ◽

Vol 150 (5) ◽

pp. 2109-2117 ◽

Cited By ~ 244

Author(s):

Elodie Riant ◽

Aurélie Waget ◽

Haude Cogo ◽

Jean-François Arnal ◽

Rémy Burcelin ◽

...

Keyword(s):

Insulin Resistance ◽

Adipose Tissue ◽

Glucose Intolerance ◽

High Fat Diet ◽

Chow Diet ◽

High Fat ◽

Normal Chow ◽

Visceral Adipose ◽

Deficient Mice ◽

Normal Chow Diet

Although corroborating data indicate that estrogens influence glucose metabolism through the activation of the estrogen receptor α (ERα), it has not been established whether this pathway could represent an effective therapeutic target to fight against metabolic disturbances induced by a high-fat diet (HFD). To this end, we first evaluated the influence of chronic 17β-estradiol (E2) administration in wild-type ovariectomized mice submitted to either a normal chow diet or a HFD. Whereas only a modest effect was observed in normal chow diet-fed mice, E2 administration exerted a protective effect against HFD-induced glucose intolerance, and this beneficial action was abolished in ERα-deficient mice. Furthermore, E2 treatment reduced HFD-induced insulin resistance by 50% during hyperinsulinemic euglycemic clamp studies and improved insulin signaling (Akt phosphorylation) in insulin-stimulated skeletal muscles. Unexpectedly, we found that E2 treatment enhanced cytokine (IL-6, TNF-α) and plasminogen activator inhibitor-1 mRNA expression induced by HFD in the liver and visceral adipose tissue. Interestingly, although the proinflammatory effect of E2 was abolished in visceral adipose tissue from chimeric mice grafted with bone marrow cells from ERα-deficient mice, the beneficial effect of the hormone on glucose tolerance was not altered, suggesting that the metabolic and inflammatory effects of estrogens can be dissociated. Eventually comparison of sham-operated with ovariectomized HFD-fed mice demonstrated that endogenous estrogens levels are sufficient to exert a full protective effect against insulin resistance and glucose intolerance. In conclusion, the regulation of the ERα pathway could represent an effective strategy to reduce the impact of high-fat diet-induced type 2 diabetes.

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