Adipose tissue depot specific expression and regulation of fibrosis-related genes and proteins in experimental obesity

Transforming growth factor beta (Tgfb) is a well-studied pro-fibrotic cytokine, which upregulates cellular communication network factor 2 (Ccn2), collagen, and actin alpha 2, smooth muscle (Acta2) expression. Obesity induces adipose tissue fibrosis, which contributes to metabolic diseases. This work aimed to analyze the expression of Tgfb, Ccn2, collagen1a1 (Col1a1), Acta2 and BMP and activin membrane-bound inhibitor (Bambi), which is a negative regulator of Tgfb signaling, in different adipose tissue depots of mice fed a standard chow, mice fed a high fat diet (HFD) and ob/ob mice. Principally, these genes were low expressed in brown adipose tissues and this difference was less evident for the ob/ob mice. Ccn2 and Bambi protein as well as mRNA expression, and collagen1a1 mRNA were not induced in the adipose tissues upon HFD feeding whereas Tgfb and Acta2 mRNA increased in the white fat depots. Immunoblot analysis showed that Acta2 protein was higher in subcutaneous and perirenal fat of these mice. In the ob/ob mice, Ccn2 mRNA and Ccn2 protein were upregulated in the fat depots. Here, Tgfb, Acta2 and Col1a1 mRNA levels and serum Tgfb protein were increased. Acta2 protein was, however, not higher in subcutaneous and perirenal fat of these mice. Col6a1 mRNA was shown before to be higher in obese fat tissues. Current analysis proved the Col6a1 protein was induced in subcutaneous fat of HFD fed mice. Notably, Col6a1 was reduced in perirenal fat of ob/ob mice in comparison to the respective controls. 3T3-L1 cells express Ccn2 and Bambi protein, whose levels were not changed by fatty acids, leptin, lipopolysaccharide, tumor necrosis factor and interleukin-6. All of these factors led to higher Tgfb in 3T3-L1 adipocyte media but did not increase its mRNA levels. Free fatty acids induced necrosis whereas apoptosis did not occur in any of the in vitro incubations excluding cell death as a main reason for higher Tgfb in cell media. In summary, Tgfb mRNA is consistently induced in white fat tissues in obesity but this is not paralleled by a clear increase of its target genes. Moreover, discrepancies between mRNA and protein expression of Acta2 were observed. Adipocytes seemingly do not contribute to higher Tgfb mRNA levels in obesity. These cells release more Tgfb protein when challenged with obesity-related metabolites connecting metabolic dysfunction and fibrosis

Chemokine-like receptor 1 mRNA weakly correlates with non-alcoholic steatohepatitis score in male but not female individuals

The chemokine-like receptor 1 (CMKLR1) ligands resolvin E1 and chemerin are known to modulate inflammatory response. The progression of non-alcoholic fatty liver disease (NAFLD) to non-alcoholic steatohepatitis (NASH) is associated with inflammation. Here it was analyzed whether hepatic CMKLR1 expression is related to histological features of NASH. Therefore, CMKLR1 mRNA was quantified in liver tissue of 33 patients without NAFLD, 47 patients with borderline NASH and 38 patients with NASH. Hepatic CMKLR1 mRNA was not associated with gender and body mass index (BMI) in the controls and the whole study group. CMKLR1 expression was similar in controls and in patients with borderline NASH and NASH. In male patients weak positive correlations with inflammation, fibrosis and NASH score were identified. In females CMKLR1 was not associated with features of NAFLD. Liver CMKLR1 mRNA tended to be higher in type 2 diabetes patients of both genders and in hypercholesterolemic women. In summary, this study shows that hepatic CMKLR1 mRNA is weakly associated with features of NASH in male patients only

Peripartum depression and anxiety as an integrative cross domain target for psychiatric preventative measures

Exposure to high levels of early life stress has been identified as a potent risk factor for neurodevelopmental delays in infants, behavioral problems and autism in children, but also for several psychiatric illnesses in adulthood, such as depression, anxiety, autism, and posttraumatic stress disorder. Despite having robust adverse effects on both mother and infant, the pathophysiology of peripartum depression and anxiety are poorly understood. The objective of this review is to highlight the advantages of using an integrated approach addressing several behavioral domains in both animal and clinical studies of peripartum depression and anxiety. It is postulated that a greater focus on integrated cross domain studies will lead to advances in treatments and preventative measures for several disorders associated with peripartum depression and anxiety. Exposure to high levels of early life stress has been identified as a potent risk factor for neurodevelopmental delays in infants, behavioral problems and autism in children, but also for several psychiatric illnesses in adulthood, such as depression, anxiety, autism, and posttraumatic stress disorder. Despite having robust adverse effects on both mother and infant, the pathophysiology of peripartum depression and anxiety are poorly understood. The objective of this review is to highlight the advantages of using an integrated approach addressing several behavioral domains in both animal and clinical studies of peripartum depression and anxiety. It is postulated that a greater focus on integrated cross domain studies will lead to advances in treatments and preventative measures for several disorders associated with peripartum depression and anxiety

Sex-stratified Genome-wide Association Studies Including 270,000 Individuals Show Sexual Dimorphism in Genetic Loci for Anthropometric Traits

Peer reviewe

Untersuchungen zur Rolle von alpha-Syntrophin in Adipozyten

Im Rahmen dieser Arbeit sollte die Rolle von alpha Syntrophin (SNTA) für die Funktionalität von Adipozyten und in der Adipositas untersucht werden. Aus der Literatur ist bekannt, dass SNTA ein Bestandteil des Dystrophin Komplexes im Skelettmuskel ist und bisher publizierte Daten beschäftigen sich fast ausschließlich mit dieser Thematik. In unserer Arbeitsgruppe wurde gezeigt, dass SNTA auch im Fettgewebe und in der Adipozytenzelllinie 3T3-L1 exprimiert wird. Die in vitro Untersuchungen an der 3T3-L1 Zelllinie, die über einen Zeitraum von neun Tagen von Präadipozyten zu reifen Adipozyten differenziert wird, ergeben, dass SNTA eine entscheidende Rolle für die Lipidspeicherung in den reifen Adipozyten hat. und die Proliferation der Präadipozyten reguliert. Der knock-down von SNTA in den Präadipozyten bewirkt eine erhöhte Proliferation der Fibroblasten. Eine niedrige Expression von SNTA während der Adipogenese verhindert die Ausbildung grosser Lipidtropfen, so dass die Triglyzeride nur in kleinen Lipidvakuolen gespeichert werden. Es ist weder der Differenzierungsgrad, die Insulinsignaltransduktion noch die Lipolyse im Vergleich zu den Kontroll-behandelten Zellen verändert. Des Weiteren ist die Expression von SCD1 nach dem knock-down von SNTA erniedrigt. Da die SCD1 im endoplasmatischen Retikulum und SNTA im Zytoplasma lokalisiert ist kann dies nicht durch eine direkte Proteininteraktion erklärt werden. SNTA knock-out Mäuse lagern weniger Lipide in den subkutanen und perirenalen Fettdepots nach Fütterung einer Hochfettdiät ein und sind vor einer nicht alkoholischen Fettlebererkrankung (NAFLD) geschützt. Die metabolische Charakterisierung der SNTA knock-out Mäuse ergibt keine wesentlichen Unterschiede in der Zusammensetzung des Serumlipidoms oder in der Entzündungsreaktion. SNTA knock-out Mäuse sind nicht vor einer Adipositas abhängigen Hyperglykämie geschützt. Allerdings wird – anders als in den Wildtyp Tieren - der Glukosespiegel nicht durch eine vermehrte Synthese von Proinsulin in den pankreatischen beta Zellen konstant gehalten. Weiterhin konnte gezeigt werden, dass SNTA eine wichtige Rolle für die Morphologie und die Expansion des Fettgewebes spielt. Nach einer Diät induzierten Adipositas expandieren die Fettdepots der SNTA knock-out Mäuse hauptsächlich über Hyperplasie und nicht, wie man erwarten würde, über Hypertrophie. Dementsprechend finden sich mehr und kleinere Zellen in den verschiedenen Fettdepots. Die ob/ob Mäusen stellen ein genetisches Adipositasmodell dar, da diese Mäuse Leptin defizient sind, weswegen sie kein Sättigungsgefühl entwickeln und somit rasch an Gewicht zunehmen. Man weiß von diesen Mäusen auch, dass sie hypertrophe Adipozyten ausbilden. In den hypertrophen Adipozyten des subkutanen Fettgewebes ist die Expression von SNTA sowohl auf Protein- als auch auf mRNA-Ebene signifikant erhöht. Wie schon in den in vitro Versuchen gezeigt ist auch im Fettgewebe und in der Leber der SNTA knock-out Mäuse die Expression von SCD1 verändert. Welche Mechanismen daran beteiligt sind, ist noch unklar, da eine direkte Interaktion ausgeschlossen werden kann und verschiedene in der Literatur beschriebene SCD1 knock-out Tiermodelle diskrepante Ergebnisse liefern. Zusammenfassend zeigt die vorliegende Arbeit, dass eine SNTA Defizienz mit einer verminderten Fettmasse, kleineren Adipozyten und einer vornehmlich hyperplastischen Expansion des Fettgewebes in der Adipositas einhergeht. Dies scheint ein direkter Effekt in den Adipozyten zu sein. Diese Tiere bilden weder eine hepatische Steatose noch eine Hyperinsulinemie aus, was sich wahrscheinlich durch die verbesserte Funktion des Fettgewebes erklären lässt

Systemic saturated lysophosphatidylcholine is associated with hepatic function in patients with liver cirrhosis.

Serum lysophosphatidylcholine (LPC) is described to decline in patients with chronic liver diseases. Here it was evaluated which of the LPC species are associated with liver function. LPC species were quantified by direct flow-injection electrospray ionization tandem mass spectrometry in serum of 45 patients with mainly alcoholic liver cirrhosis. Saturated LPC is 52.1 (31.7-110.0) μmol/l in serum of patients with CHILD-PUGH score C (decompensated liver cirrhosis) and significantly lower compared to patients with well-compensated disease (CHILD-PUGH score A) with 114.1 (12.3-401.4) μmol/l. Mono- and polyunsaturated LPC are not changed in these groups. Saturated LPC is negatively correlated with the model for end-stage liver disease score, bilirubin and galectin-3 and positively with Quick prothrombin time. Ascites and varices are complications of liver cirrhosis. Saturated LPC does, however, not correlate with hepatic venous pressure gradient, ascites volume and variceal size. Unexpectedly, saturated LPC measured in serum of 42 patients declines from 88.4 (27.8-177.5) μmol/l to 72.4 (27.6-141.8) μmol/l shortly after transjugular intrahepatic portosystemic shunt implantation. Hepatic vein saturated LPC (82.3 (12.4-161.7) μmol/l) is higher than portal vein levels (78.8 (10.1-161.0) μmol/l) suggesting hepatic release of this lipid species. Current data demonstrate that systemic saturated LPC species are reduced in patients with decompensated liver cirrhosis and associated with mortality risk

Reduced serum chemerin in patients with more severe liver cirrhosis

Chemerin is a well-established modulator of immune cell function and its serum levels are induced in inflammatory diseases. Liver cirrhosis is associated with inflammation which is aggravated by portal hypertension. The objective of this study was to evaluate whether chemerin is induced in patients with more severe liver cirrhosis and portal hypertension. Chemerin has been measured by ELISA in the portal venous serum (PVS), systemic venous serum (SVS) and hepatic venous serum (HVS) of 45 patients with liver cirrhosis. Chemerin is higher in HVS compared to PVS in accordance with our recently published finding. SVS, HVS and PVS chemerin decline in patients with more advanced liver injury defined by the CHILD-PUGH score. Hepatic chemerin has been determined in a small cohort and is similarly expressed in normal and cirrhotic liver. MELD score and serum markers of liver and kidney function do not correlate with chemerin. There is a positive correlation of chemerin in all compartments with Quick prothrombin time and of SVS chemerin with systolic blood pressure. PVS chemerin is induced in patients with modest/massive ascites but this does not translate into higher HVS and SVS levels. Chemerin is not associated with variceal size. Reduction of portal pressure by transjugular intrahepatic portosystemic shunt does not affect chemerin levels. These data show that low chemerin in patients with more severe liver cirrhosis is associated with reduced Quick prothrombin time

The adaptor protein alpha-syntrophin regulates adipocyte lipid droplet growth

The scaffold protein alpha-syntrophin (SNTA) regulates lipolysis indicating a role in lipid homeostasis. Adipocytes are the main lipid storage cells in the body, and here, the function of SNTA has been analyzed in 3T3-L1 cells. SNTA is expressed in preadipocytes and is induced early during adipogenesis. Knockdown of SNTA in preadipocytes increases their proliferation. Proteins which are induced during adipogenesis like adiponectin and caveolin-1, and the inflammatory cytokine IL-6 are at normal levels in the mature cells differentiated from preadipocytes with low SNTA. This suggests that SNTA does neither affect differentiation nor inflammation. Expression of proteins with a role in cholesterol and triglyceride homeostasis is unchanged. Consequently, basal and epinephrine induced lipolysis as well as insulin stimulated phosphorylation of Akt and ERK1/2 are normal. Importantly, adipocytes with low SNTA form smaller lipid droplets and store less triglycerides. Stearoyl-CoA reductase and MnSOD are reduced upon SNTA knock-down but do not contribute to lower lipid levels. Oleate uptake is even increased in cells with SNTA knock-down. In summary, current data show that SNTA is involved in the expansion of lipid droplets independent of adipogenesis. Enhanced preadipocyte proliferation and capacity to store surplus fatty acids may protect adipocytes with low SNTA from lipotoxicity in obesity. (C) 2016 Elsevier Inc. All rights reserved

Connective tissue growth factor level is increased in patients with liver cirrhosis but is not associated with complications or extent of liver injury

Connective tissue growth factor (CTGF) is a profibrotic protein whose systemic levels are increased in liver cirrhosis. Here, association of CTGF with stages of liver injury and complications of cirrhotic liver disease has been analyzed in patients with different aetiologies of hepatic injury. CTGF is significantly increased in portal venous serum (PVS), hepatic venous serum (HVS) and systemic venous serum (SVS) of 46 patients with liver cirrhosis compared to eight liver-healthy controls. In patients´ blood samples CTGF in HVS is about 6% higher than PVS levels indicating that CTGF produced in the liver is released to the circulation. CTGF is not associated with stages of liver cirrhosis defined by CHILD-PUGH or MELD score nor with secondary complications of portal hypertension (varices, ascites, spontaneous bacterial peritonitis). Transforming growth factor β (TGFβ) induces CTGF synthesis in hepatocytes and a positive association of systemic TGFβ1 and SVS and HVS CTGF is found. Three months after placing transjugular intrahepatic portosystemic shunt (TIPS) hepatic venous pressure gradient is reduced whereas CHILD-PUGH score, TGFβ1 and CTGF are not altered in serum of 15 patients. Current data show that the cirrhotic liver releases little CTGF but SVS, HVS and PVS CTGF levels are not associated with residual liver function and complications of cirrhosis

Circulating lipocalin 2 is neither related to liver steatosis in patients with non-alcoholic fatty liver disease nor to residual liver function in cirrhosis.

Lipocalin 2 (LCN2) is induced in the injured liver and associated with inflammation. Aim of the present study was to evaluate whether serum LCN2 is a non-invasive marker to assess hepatic steatosis in patients with non-alcoholic fatty liver disease (NAFLD) or residual liver function in patients with liver cirrhosis. Therefore, LCN2 was measured by ELISA in serum of 32 randomly selected patients without fatty liver (controls), 24 patients with ultrasound diagnosed NAFLD and 42 patients with liver cirrhosis mainly due to alcohol. Systemic LCN2 was comparable in patients with liver steatosis, those with liver cirrhosis and controls. LCN2 negatively correlated with bilirubin in both cohorts. In cirrhosis, LCN2 was not associated with more advanced liver injury defined by the CHILD-PUGH score and model for end-stage liver disease score. Resistin but not C-reactive protein or chemerin positively correlated with LCN2. LCN2 levels were not increased in patients with ascites or patients with esophageal varices. Consequently, reduction of portal pressure by transjugular intrahepatic portosystemic shunt did not affect LCN2 levels. Hepatic venous blood (HVS), portal venous blood and systemic venous blood levels of LCN2 were similar. HVS LCN2 was unchanged in patients with end-stage liver cirrhosis compared to those with well-compensated disease arguing against increased hepatic release. Current data exclude that serum LCN2 is of any value as steatosis marker in patients with NAFLD and indicator of liver function in patients with alcoholic liver cirrhosis