scholarly journals The Fate of Dietary Cholesterol in the Kissing Bug Rhodnius prolixus

2021 ◽  
Vol 12 ◽  
Author(s):  
Petter F. Entringer ◽  
David Majerowicz ◽  
Katia C. Gondim
Keyword(s):  
Fat Body ◽  
Control Strategies ◽  
Dietary Cholesterol ◽  
Cholesterol Absorption ◽  
Rhodnius Prolixus ◽  
Free Form ◽  
Cholesterol Transport ◽  
Membrane Composition ◽  
Hormone Production ◽  
Anterior Midgut

Insects are unable to synthesize cholesterol and depend on the presence of sterols in the diet for cell membrane composition and hormone production. Thus, cholesterol absorption, transport, and metabolism are potential targets for vector and pest control strategies. Here, we investigate the dietary cholesterol absorption and tissue distribution in the kissing bug Rhodnius prolixus using radiolabeled cholesterol. Both the anterior and posterior midguts absorbed cholesterol from the ingested blood, although the anterior midgut absorbed more. We also observed esterified cholesterol labeling in the epithelium, indicating that midgut cells can metabolize and store cholesterol. Only a small amount of labeled cholesterol was found in the hemolymph, where it was mainly in the free form and associated with lipophorin (Lp). The fat body transiently accumulated cholesterol, showing a labeled cholesterol peak on the fifth day after the blood meal. The ovaries also incorporated cholesterol, but cumulatively. The insects did not absorb almost half of the ingested labeled cholesterol, and radioactivity was present in the feces. After injection of 3H-cholesterol-labeled Lp into females, a half-life of 5.5 ± 0.7 h in the hemolymph was determined. Both the fat body and ovaries incorporated Lp-associated cholesterol, which was inhibited at low temperature, indicating the participation of active cholesterol transport. These results help describe an unexplored part of R. prolixus lipid metabolism.

scholarly journals A role for NPC1 and NPC2 in intestinal cholesterol absorption – the hypothesis gutted

2007 ◽  
Vol 408 (1) ◽  
Author(s):  
Laura Liscum
Keyword(s):  
Endoplasmic Reticulum ◽  
Dietary Cholesterol ◽  
Cholesterol Absorption ◽  
Cholesterol Transport ◽  
Intestinal Epithelial ◽  
Intestinal Cholesterol Absorption ◽  
Biochemical Journal ◽  
Good Target ◽  
Type C ◽  
Niemann Pick

Dietary and biliary cholesterol are taken up by intestinal epithelial cells and transported to the endoplasmic reticulum. At the endoplasmic reticulum, cholesterol is esterified, packaged into chylomicrons and secreted into the lymph for delivery to the bloodstream. NPC1L1 (Niemann–Pick C1-like 1) is a protein on the enterocyte brush-border membrane that facilitates cholesterol absorption. Cholesterol's itinerary as it moves to the endoplasmic reticulum is unknown, as is the identity of any cellular proteins that facilitate the movement. Two proteins that play an important role in intracellular cholesterol transport and could potentially influence NPC1L1-mediated cholesterol uptake are NPC1 and NPC2 (Niemann–Pick type C disease proteins 1 and 2). In this issue of the Biochemical Journal, Dixit and colleagues show that the absence or presence of NPC1 and NPC2 has no effect on intestinal cholesterol absorption in the mouse. Thus neither protein fills the gap in our knowledge of intra-enterocyte cholesterol transport. Furthermore, the NPC1/NPC2 pathway would not be a good target for limiting the uptake of dietary cholesterol.

scholarly journals Influence of Serratia marcescens and Rhodococcus rhodnii on the Humoral Immunity of Rhodnius prolixus

2021 ◽  
Vol 22 (20) ◽  
pp. 10901
Author(s):  
Kate K. S. Batista ◽  
Cecília S. Vieira ◽  
Marcela B. Figueiredo ◽  
Samara G. Costa-Latgé ◽  
Patrícia Azambuja ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Trypanosoma Cruzi ◽  
Serratia Marcescens ◽  
Immune Modulation ◽  
Fat Body ◽  
Bacterial Load ◽  
Rhodnius Prolixus ◽  
Limiting Factor ◽  
Phenoloxidase Activity ◽  
Anterior Midgut

Chagas disease is a human infectious disease caused by Trypanosoma cruzi and can be transmitted by triatomine vectors, such as Rhodnius prolixus. One limiting factor for T. cruzi development is the composition of the bacterial gut microbiota in the triatomine. Herein, we analyzed the humoral immune responses of R. prolixus nymphs treated with antibiotics and subsequently recolonized with either Serratia marcescens or Rhodococcus rhodnii. The treatment with antibiotics reduced the bacterial load in the digestive tract, and the recolonization with each bacterium was successfully detected seven days after treatment. The antibiotic-treated insects, recolonized with S. marcescens, presented reduced antibacterial activity against Staphylococcus aureus and phenoloxidase activity in hemolymph, and lower nitric oxide synthase (NOS) and higher defensin C gene (DefC) gene expression in the fat body. These insects also presented a higher expression of DefC, lower prolixicin (Prol), and lower NOS levels in the anterior midgut. However, the antibiotic-treated insects recolonized with R. rhodnii had increased antibacterial activity against Escherichia coli and lower activity against S. aureus, higher phenoloxidase activity in hemolymph, and lower NOS expression in the fat body. In the anterior midgut, these insects presented higher NOS, defensin A (DefA) and DefC expression, and lower Prol expression. The R. prolixus immune modulation by these two bacteria was observed not only in the midgut, but also systemically in the fat body, and may be crucial for the development and transmission of the parasites Trypanosoma cruzi and Trypanosoma rangeli.

Progress in the Mechanism of Dietary Cholesterol Absorption

2012 ◽  
Vol 28 (7) ◽  
pp. 573
Author(s):  
Yingyu ZHANG ◽  
Baoliang SONG
Keyword(s):  
Dietary Cholesterol ◽  
Cholesterol Absorption

Modulation of intestinal cholesterol absorption by high glucose levels: impact on cholesterol transporters, regulatory enzymes, and transcription factors

2008 ◽  
Vol 295 (5) ◽  
pp. G873-G885 ◽  
Author(s):  
Z. Ravid ◽  
M. Bendayan ◽  
E. Delvin ◽  
A. T. Sane ◽  
M. Elchebly ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Protein Expression ◽  
High Glucose ◽  
Cholesterol Absorption ◽  
Cholesterol Homeostasis ◽  
Cholesterol Transport ◽  
Intestinal Cholesterol Absorption ◽  
Cholesterol Uptake ◽  
Glucose Levels

Growing evidence suggests that the small intestine may contribute to excessive postprandial lipemia, which is highly prevalent in insulin-resistant/Type 2 diabetic individuals and substantially increases the risk of cardiovascular disease. The aim of the present study was to determine the role of high glucose levels on intestinal cholesterol absorption, cholesterol transporter expression, enzymes controlling cholesterol homeostasis, and the status of transcription factors. To this end, we employed highly differentiated and polarized cells (20 days of culture), plated on permeable polycarbonate filters. In the presence of [14C]cholesterol, glucose at 25 mM stimulated cholesterol uptake compared with Caco-2/15 cells supplemented with 5 mM glucose ( P < 0.04). Because combination of 5 mM glucose with 20 mM of the structurally related mannitol or sorbitol did not change cholesterol uptake, we conclude that extracellular glucose concentration is uniquely involved in the regulation of intestinal cholesterol transport. The high concentration of glucose enhanced the protein expression of the critical cholesterol transporter NPC1L1 and that of CD36 ( P < 0.02) and concomitantly decreased SR-BI protein mass ( P < 0.02). No significant changes were observed in the protein expression of ABCA1 and ABCG8, which act as efflux pumps favoring cholesterol export out of absorptive cells. At the same time, 3-hydroxy-3-methylglutaryl-coenzyme A reductase activity was decreased ( P < 0.007), whereas ACAT activity remained unchanged. Finally, increases were noted in the transcription factors LXR-α, LXR-β, PPAR-β, and PPAR-γ along with a drop in the protein expression of SREBP-2. Collectively, our data indicate that glucose at high concentrations may regulate intestinal cholesterol transport and metabolism in Caco-2/15 cells, thus suggesting a potential influence on the cholesterol absorption process in Type 2 diabetes.

scholarly journals Use of NBD-cholesterol to identify a minor but NPC1L1-independent cholesterol absorption pathway in mouse intestine

2011 ◽  
Vol 300 (1) ◽  
pp. G164-G169 ◽  
Author(s):  
Michelle R. Adams ◽  
Eddy Konaniah ◽  
James G. Cash ◽  
David Y. Hui
Keyword(s):  
Intestinal Mucosa ◽  
Cholesterol Absorption ◽  
Intestinal Lumen ◽  
Cholesterol Transport ◽  
Cholesteryl Esters ◽  
Main Function ◽  
Absorption Mechanism ◽  
Ezetimibe Treatment ◽  
Niemann Pick ◽  
A Minor

The importance of Niemann-Pick C1 Like-1 (NPC1L1) protein in intestinal absorption of dietary sterols, including both cholesterol and phytosterols, is well documented. However, the exact mechanism by which NPC1L1 facilitates cholesterol transport remains controversial. This study administered 22-( N(-7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-23,24-bisnor-5-cholen-3β-ol (NBD-cholesterol) and [3H]cholesterol to Npc1l1+/+ and Npc1l1−/− mice to determine whether NPC1L1 facilitates dietary sterol uptake by enterocytes and/or participates in intracellular sterol delivery to the endoplasmic reticulum (ER) for lipoprotein assembly before secretion into plasma circulation. Results showed that [3H]cholesterol absorption was reduced but not abolished in Npc1l1−/− mice compared with Npc1l1+/+ mice. In the presence of Pluronic L-81 to block pre-chylomicron exit from the ER, significant amounts of [3H]cholesterol were found to be associated with lipid droplets in the intestinal mucosa of both Npc1l1+/+ and Npc1l1−/− mice, and the intracellular [3H]cholesterol can be esterified to cholesteryl esters. These results provided evidence indicating that the main function of NPC1L1 is to promote cholesterol uptake from the intestinal lumen but that it is not necessary for intracellular cholesterol transport to the ER. Surprisingly, NBD-cholesterol was taken up by intestinal mucosa, esterified to NBD-cholesteryl esters, and transported to plasma circulation to similar extent between Npc1l1+/+ and Npc1l1−/− mice. Ezetimibe treatment also had no impact on NBD-cholesterol absorption by Npc1l1+/+ mice. Thus, NBD-cholesterol absorption proceeds through an NPC1L1-independent and ezetimibe-insensitive sterol absorption mechanism. Taken together, these results indicate that NBD-cholesterol can be used to trace the alternative cholesterol absorption pathway but is not suitable for tracking NPC1L1-mediated cholesterol absorption.

scholarly journals Dietary cholesterol absorption, and sterol and bile acid excretion in hypercholesterolemia-resistant white rabbits.

1990 ◽  
Vol 31 (11) ◽  
pp. 2019-2027
Author(s):  
ML Overturf ◽  
SA Smith ◽  
AM Gotto ◽  
JD Morrisett ◽  
T Tewson ◽  
...  
Keyword(s):  
Bile Acid ◽  
Dietary Cholesterol ◽  
Cholesterol Absorption ◽  
Acid Excretion ◽  
Bile Acid Excretion

scholarly journals MicroRNA-8 targets the Wingless signaling pathway in the female mosquito fat body to regulate reproductive processes

2015 ◽  
Vol 112 (5) ◽  
pp. 1440-1445 ◽  
Author(s):  
Keira J. Lucas ◽  
Sourav Roy ◽  
Jisu Ha ◽  
Amanda L. Gervaise ◽  
Vladimir A. Kokoza ◽  
...  
Keyword(s):  
Blood Meal ◽  
Molecular Mechanisms ◽  
Fat Body ◽  
Control Strategies ◽  
Functional Characterization ◽  
Target Prediction ◽  
Underlying Mechanism ◽  
Female Mosquito ◽  
Reproductive Events

Female mosquitoes require a blood meal for reproduction, and this blood meal provides the underlying mechanism for the spread of many important vector-borne diseases in humans. A deeper understanding of the molecular mechanisms linked to mosquito blood meal processes and reproductive events is of particular importance for devising innovative vector control strategies. We found that the conserved microRNA miR-8 is an essential regulator of mosquito reproductive events. Two strategies to inhibit miR-8 function in vivo were used for functional characterization: systemic antagomir depletion and spatiotemporal inhibition using the miRNA sponge transgenic method in combination with the yeast transcriptional activator gal4 protein/upstream activating sequence system. Depletion of miR-8 in the female mosquito results in defects related to egg development and deposition. We used a multialgorithm approach for miRNA target prediction in mosquito 3′ UTRs and experimentally verified secreted wingless-interacting molecule (swim) as an authentic target of miR-8. Our findings demonstrate that miR-8 controls the activity of the long-range Wingless (Wg) signaling by regulating Swim expression in the female fat body. We discovered that the miR-8/Wg axis is critical for the proper secretion of lipophorin and vitellogenin by the fat body and subsequent accumulation of these yolk protein precursors by developing oocytes.

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