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The great roundleaf bat (Hipposideros armiger) as a good model for cold-induced browning of intra-abdominal white adipose tissue.

Wang Y, Zhu T, Ke S, Fang N, Irwin DM, Lei M, Zhang J, Shi H, Zhang S, Wang Z - PLoS ONE (2014)

Bottom Line: Adipocyte diameters of WATs became significantly reduced and the white adipocytes became brown-like in morphology.Interestingly, the rickett's big-footed bat did not show such a tendency in beige fat.Combined with rodent models, this model should be helpful for finding therapies for reducing harmful aWAT in humans.

View Article: PubMed Central - PubMed

Affiliation: Institute of Molecular Ecology and Evolution, East China Normal University, Shanghai, China.

ABSTRACT

Background: Inducing beige fat from white adipose tissue (WAT) is considered to be a shortcut to weight loss and increasingly becoming a key area in research into treatments for obesity and related diseases. However, currently, animal models of beige fat are restricted to rodents, where subcutaneous adipose tissue (sWAT, benign WAT) is more liable to develop into the beige fat under specific activators than the intra-abdominal adipose tissue (aWAT, malignant WAT) that is the major source of obesity related diseases in humans.

Methods: Here we induced beige fat by cold exposure in two species of bats, the great roundleaf bat (Hipposideros armiger) and the rickett's big-footed bat (Myotis ricketti), and compared the molecular and morphological changes with those seen in the mouse. Expression of thermogenic genes (Ucp1 and Pgc1a) was measured by RT-qPCR and adipocyte morphology examined by HE staining at three adipose locations, sWAT, aWAT and iBAT (interscapular brown adipose tissue).

Results: Expression of Ucp1 and Pgc1a was significantly upregulated, by 729 and 23 fold, respectively, in aWAT of the great roundleaf bat after exposure to 10°C for 7 days. Adipocyte diameters of WATs became significantly reduced and the white adipocytes became brown-like in morphology. In mice, similar changes were found in the sWAT, but much lower amounts of changes in aWAT were seen. Interestingly, the rickett's big-footed bat did not show such a tendency in beige fat.

Conclusions: The great roundleaf bat is potentially a good animal model for human aWAT browning research. Combined with rodent models, this model should be helpful for finding therapies for reducing harmful aWAT in humans.

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Related in: MedlinePlus

Schematic diagram of intra-abdominal adipose tissue (aWAT), and changes in body weight of bats and mice after exposure to cold temperatures.(a–b) Schematic diagram of aWAT in the bat (a) and mouse (b). Tissues depicted in yellow are aWAT studied here. mWAT: mesenteric WAT; eWAT: epididymal WAT. (c–d) Changes in the body weighs of bats (c) and mice (d), where one group was kept at room temperature (25°C) and the other at 10°C. Each group was composed of 6 individuals. Data are expressed as means ± SD. Statistical significance is marked above the bars: *, p<0.05.
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pone-0112495-g002: Schematic diagram of intra-abdominal adipose tissue (aWAT), and changes in body weight of bats and mice after exposure to cold temperatures.(a–b) Schematic diagram of aWAT in the bat (a) and mouse (b). Tissues depicted in yellow are aWAT studied here. mWAT: mesenteric WAT; eWAT: epididymal WAT. (c–d) Changes in the body weighs of bats (c) and mice (d), where one group was kept at room temperature (25°C) and the other at 10°C. Each group was composed of 6 individuals. Data are expressed as means ± SD. Statistical significance is marked above the bars: *, p<0.05.

Mentions: After temperature acclimation, bats and mice were euthanized by cervical dislocation. Adipose tissues were divided into two sides (left and right). One side was used for RNA extraction, and the other was fixed in 4% paraformaldehyde (PFA, Sigma-Aldrich, St. Louis, MO, USA) for morphological study. Three types of adipose tissues were collected (iBAT, sWAT and aWAT). Depot of the classical interscapular brown adipose tissue (iBAT) is the largest BAT reservoir in mammals. Subcutaneous adipose tissue (sWAT) was collected from adipocytes beneath the skin and above the abdominal wall in bats and from the inguen in the mice. Intra-abdominal white adipose tissue (aWAT) was collected from the fat tissue between the abdominal wall and the viscera, which includes some epididymal WAT but excludes mesenteric WAT (Figure 2a and b) [37].


The great roundleaf bat (Hipposideros armiger) as a good model for cold-induced browning of intra-abdominal white adipose tissue.

Wang Y, Zhu T, Ke S, Fang N, Irwin DM, Lei M, Zhang J, Shi H, Zhang S, Wang Z - PLoS ONE (2014)

Schematic diagram of intra-abdominal adipose tissue (aWAT), and changes in body weight of bats and mice after exposure to cold temperatures.(a–b) Schematic diagram of aWAT in the bat (a) and mouse (b). Tissues depicted in yellow are aWAT studied here. mWAT: mesenteric WAT; eWAT: epididymal WAT. (c–d) Changes in the body weighs of bats (c) and mice (d), where one group was kept at room temperature (25°C) and the other at 10°C. Each group was composed of 6 individuals. Data are expressed as means ± SD. Statistical significance is marked above the bars: *, p<0.05.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4231071&req=5

pone-0112495-g002: Schematic diagram of intra-abdominal adipose tissue (aWAT), and changes in body weight of bats and mice after exposure to cold temperatures.(a–b) Schematic diagram of aWAT in the bat (a) and mouse (b). Tissues depicted in yellow are aWAT studied here. mWAT: mesenteric WAT; eWAT: epididymal WAT. (c–d) Changes in the body weighs of bats (c) and mice (d), where one group was kept at room temperature (25°C) and the other at 10°C. Each group was composed of 6 individuals. Data are expressed as means ± SD. Statistical significance is marked above the bars: *, p<0.05.
Mentions: After temperature acclimation, bats and mice were euthanized by cervical dislocation. Adipose tissues were divided into two sides (left and right). One side was used for RNA extraction, and the other was fixed in 4% paraformaldehyde (PFA, Sigma-Aldrich, St. Louis, MO, USA) for morphological study. Three types of adipose tissues were collected (iBAT, sWAT and aWAT). Depot of the classical interscapular brown adipose tissue (iBAT) is the largest BAT reservoir in mammals. Subcutaneous adipose tissue (sWAT) was collected from adipocytes beneath the skin and above the abdominal wall in bats and from the inguen in the mice. Intra-abdominal white adipose tissue (aWAT) was collected from the fat tissue between the abdominal wall and the viscera, which includes some epididymal WAT but excludes mesenteric WAT (Figure 2a and b) [37].

Bottom Line: Adipocyte diameters of WATs became significantly reduced and the white adipocytes became brown-like in morphology.Interestingly, the rickett's big-footed bat did not show such a tendency in beige fat.Combined with rodent models, this model should be helpful for finding therapies for reducing harmful aWAT in humans.

View Article: PubMed Central - PubMed

Affiliation: Institute of Molecular Ecology and Evolution, East China Normal University, Shanghai, China.

ABSTRACT

Background: Inducing beige fat from white adipose tissue (WAT) is considered to be a shortcut to weight loss and increasingly becoming a key area in research into treatments for obesity and related diseases. However, currently, animal models of beige fat are restricted to rodents, where subcutaneous adipose tissue (sWAT, benign WAT) is more liable to develop into the beige fat under specific activators than the intra-abdominal adipose tissue (aWAT, malignant WAT) that is the major source of obesity related diseases in humans.

Methods: Here we induced beige fat by cold exposure in two species of bats, the great roundleaf bat (Hipposideros armiger) and the rickett's big-footed bat (Myotis ricketti), and compared the molecular and morphological changes with those seen in the mouse. Expression of thermogenic genes (Ucp1 and Pgc1a) was measured by RT-qPCR and adipocyte morphology examined by HE staining at three adipose locations, sWAT, aWAT and iBAT (interscapular brown adipose tissue).

Results: Expression of Ucp1 and Pgc1a was significantly upregulated, by 729 and 23 fold, respectively, in aWAT of the great roundleaf bat after exposure to 10°C for 7 days. Adipocyte diameters of WATs became significantly reduced and the white adipocytes became brown-like in morphology. In mice, similar changes were found in the sWAT, but much lower amounts of changes in aWAT were seen. Interestingly, the rickett's big-footed bat did not show such a tendency in beige fat.

Conclusions: The great roundleaf bat is potentially a good animal model for human aWAT browning research. Combined with rodent models, this model should be helpful for finding therapies for reducing harmful aWAT in humans.

Show MeSH
Related in: MedlinePlus