Sarah Appel

Dr. Sarah Appel

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Research Focus & Metrics

Academic Career Length

17Years (2010-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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22 January 2020 in Nutrients
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Journal Article
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TKTobias Kretschmer
Tobias Kretschmer
MSMerle Schulze-Edinghausen
Merle Schulze-Edinghausen
ETEva-Maria Turnwald
Eva-Maria Turnwald
RJRuth Janoschek
Ruth Janoschek
IBInga Bae-Gartz
Inga Bae-Gartz
SASarah Appel
Sarah Appel
Obesity during pregnancy is a known health risk for mother and child. Since obesity is associated with increased inflammatory markers, our objectives were to determine interleukin-6 (IL-6) levels in obese mice and to examine the effect of IL-6 on placental endothelial cells. Placentas, blood, and adipose tissue of C57BL/6N mice, kept on high fat diet before and during pregnancy, were harvested at E15.5. Serum IL-6 levels were determined and endothelial cell markers and IL-6 expression were measured by qRT-PCR and western blot. Immunostaining was used to determine surface and length densities of fetal capillary profiles and placental endothelial cell homeostasis. Human placental vein endothelial cells were cultured and subjected to proliferation, apoptosis, senescence, and tube formation assays after stimulation with hyperIL-6. Placental endothelial cell markers were downregulated and the percentage of senescent endothelial cells was higher in the placental exchange zone of obese dams and placental vascularization was strongly reduced. Additionally, maternal IL-6 serum levels and IL-6 protein levels in adipose tissue were increased. Stimulation with hyperIL-6 provoked a dose dependent increase of senescence in cultured endothelial cells without any effects on proliferation or apoptosis. Diet-induced maternal obesity led to an IUGR phenotype accompanied by increased maternal IL-6 serum levels. In the placenta of obese dams, this may result in a disturbed endothelial cell homeostasis and impaired fetal vasculature. Cell culture experiments confirmed that IL-6 is capable of inducing endothelial cell senescence.

19 May 2021 in Cells
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Journal Article
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PKPhilipp Kasper
Philipp Kasper
SBSaida Breuer
Saida Breuer
THThorben Hoffmann
Thorben Hoffmann
CVChristina Vohlen
Christina Vohlen
RJRuth Janoschek
Ruth Janoschek
IBInga Bae-Gartz
Inga Bae-Gartz
Maternal obesity is associated with an increased risk of hepatic metabolic dysfunction for both mother and offspring and targeted interventions to address this growing metabolic disease burden are urgently needed. This study investigates whether maternal exercise (ME) could reverse the detrimental effects of hepatic metabolic dysfunction in obese dams and their offspring while focusing on the AMP-activated protein kinase (AMPK), representing a key regulator of hepatic metabolism. In a mouse model of maternal western-style-diet (WSD)-induced obesity, we established an exercise intervention of voluntary wheel-running before and during pregnancy and analyzed its effects on hepatic energy metabolism during developmental organ programming. ME prevented WSD-induced hepatic steatosis in obese dams by alterations of key hepatic metabolic processes, including activation of hepatic ß-oxidation and inhibition of lipogenesis following increased AMPK and peroxisome-proliferator-activated-receptor-γ-coactivator-1α (PGC-1α)-signaling. Offspring of exercised dams exhibited a comparable hepatic metabolic signature to their mothers with increased AMPK-PGC1α-activity and beneficial changes in hepatic lipid metabolism and were protected from WSD-induced adipose tissue accumulation and hepatic steatosis in later life. In conclusion, this study demonstrates that ME provides a promising strategy to improve the metabolic health of both obese mothers and their offspring and highlights AMPK as a potential metabolic target for therapeutic interventions.

13 March 2024 in Cells
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Journal Article
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ENEva Nüsken
Eva Nüsken
SASarah Appel
Sarah Appel
LSLeon Saschin
Leon Saschin
CKCentina Kuiper-Makris
Centina Kuiper-Makris
LOLaura Oberholz
Laura Oberholz
KNKai-Dietrich Nüsken
Kai-Dietrich Nüsken
Intrauterine growth restriction (IUGR) and being small for gestational age (SGA) are two distinct conditions with different implications for short- and long-term child development. SGA is present if the estimated fetal or birth weight is below the tenth percentile. IUGR can be identified by additional abnormalities (pathological Doppler sonography, oligohydramnion, lack of growth in the interval, estimated weight below the third percentile) and can also be present in fetuses and neonates with weights above the tenth percentile. There is a need to differentiate between IUGR and SGA whenever possible, as IUGR in particular is associated with greater perinatal morbidity, prematurity and mortality, as well as an increased risk for diseases in later life. Recognizing fetuses and newborns being “at risk” in order to monitor them accordingly and deliver them in good time, as well as to provide adequate follow up care to ameliorate adverse sequelae is still challenging. This review article discusses approaches to differentiate IUGR from SGA and further increase diagnostic accuracy. Since adverse prenatal influences increase but individually optimized further child development decreases the risk of later diseases, we also discuss the need for interdisciplinary follow-up strategies during childhood. Moreover, we present current concepts of pathophysiology, with a focus on oxidative stress and consecutive inflammatory and metabolic changes as key molecular mechanisms of adverse sequelae, and look at future scientific opportunities and challenges. Most importantly, awareness needs to be raised that pre- and postnatal care of IUGR neonates should be regarded as a continuum.

10 December 2018 in Endocrinology
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SASarah Appel
Sarah Appel
JGJon Grothe
Jon Grothe
SSSarah Storck
Sarah Storck
RJRuth Janoschek
Ruth Janoschek
IBInga Bae-Gartz
Inga Bae-Gartz
JDJörg Dötsch
Jörg Dötsch
Obesity and an unhealthy nutrition are on the rise and affect also women in childbearing age and hence, during pregnancy. Despite normal or even high birth weight the offspring suffers from long term metabolic risks. We hypothesized that fetal growth is disturbed during different intrauterine phases. Underlying molecular events remain elusive. Female mice were fed either a control diet (SD) or a high fat diet (HFD) after weaning until mating and during pregnancy. Pregnant mice were sacrificed at gestational time points G15.5 and G18.5 and fetuses and placentas were removed for analysis. HFD fetuses displayed intrauterine growth restriction (IUGR) at G15.5, which disappeared until G18.5, indicating an intrauterine catch-up growth during that time period. Main placental findings indicate decreased canonical Wnt-GSK3beta signaling and lower proliferation rates at G18.5 which goes along with a smaller placental transfer zone. On the other hand, glucose depots (glycogen cluster) in HFD placentas decreased stronger between G15.5 and G18.5 compared to placentas from SD mothers, and the glucose transporter protein GLUT-1 was increased at G18.5 in the HFD group. Maternal diet-induced obesity causes an IUGR phenotype at the beginning of the third week (G15.5) in our mouse model. This phenotype is reversed by the end of the third week (G18.5) despite of a smaller placental transfer zone, probably based on GSK3beta-mediated increased glucose mobilization in the placenta and hence an increased glucose supply to the fetus.

22 July 2014 in PLOS ONE
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Journal Article
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SASarah Appel
Sarah Appel
JAJanina Ankerne
Janina Ankerne
JAJan Appel
Jan Appel
AOAndré Oberthuer
André Oberthuer
PMPeter Mallmann
Peter Mallmann
JDJörg Dötsch
Jörg Dötsch
CNN3 is an ubiquitously expressed F-actin binding protein, shown to regulate trophoblast fusion and hence seems to play a role in the placentation process. In this study we demonstrate that CNN3 levels are upregulated under low oxygen conditions in the trophoblast cell line BeWo. Since hypoxia is discussed to be a pro-migratory stimulus for placental cells, we examined if CNN3 is involved in trophoblast invasion. Indeed, when performing a matrigel invasion assay we were able to show that CNN3 promotes BeWo cell invasion. Moreover, CNN3 activates the MAPKs ERK1/2 and p38 in trophoblast cells and interestingly, both kinases are involved in BeWo invasion. However, when we repeated the experiments under hypoxic conditions, CNN3 did neither promote cell invasion nor MAPK activation. These results indicate that CNN3 promotes invasive processes by the stimulation of ERK1/2 and/or p38 under normoxic conditions in BeWo cells, but seems to have different functions at low oxygen levels. We further speculated that CNN3 expression might be altered in human placentas derived from pregnancies complicated by IUGR and preeclampsia, since these placental disorders have been described to go along with impaired trophoblast invasion. Our studies show that, at least in our set of placenta samples, CNN3 expression is neither deregulated in IUGR nor in preeclampsia. In summary, we identified CNN3 as a new pro-invasive protein in trophoblast cells that is induced under low oxygen conditions.

Verified
Journal Article
Open access
PDF file
ENEva Nüsken
Eva Nüsken
ETEva-Maria Turnwald
Eva-Maria Turnwald
GFGregor Fink
Gregor Fink
JVJenny Voggel
Jenny Voggel
CYChristopher Yosy
Christopher Yosy
SASarah Appel
Sarah Appel
There is accumulating evidence for fetal programming of later kidney disease by maternal obesity or associated conditions. We performed a hypothesis-generating study to identify potentially underlying mechanisms. Female mice were randomly split in two groups and fed either a standard diet (SD) or high fat diet (HFD) from weaning until mating and during pregnancy. Half of the dams from both groups were treated with metformin ((M), 380 mg/kg), resulting in four experimental groups (SD, SD-M, HFD, HFD-M). Caesarean section was performed on gestational day 18.5. Fetal kidney tissue was isolated from cryo-slices using laser microdissection methods and a proteomic screen was performed. For single proteins, a fold change ≥1.5 and q-value <0.05 were considered to be statistically significant. Interestingly, HFD versus SD had a larger effect on the proteome of fetal kidneys (56 proteins affected; interaction clusters shown for proteins concerning transcription/translation, mitochondrial processes, eicosanoid metabolism, H2S-synthesis and membrane remodeling) than metformin exposure in either SD (29 proteins affected; clusters shown for proteins involved in transcription/translation) or HFD (6 proteins affected; no cluster). By further analysis, ATP6V1G1, THY1, PRKCA and NDUFB3 were identified as the most promising candidates potentially mediating reprogramming effects of metformin in a maternal high fat diet.