Control of brown adipose tissue adaptation to nutrient stress by the activin receptor ALK7

  1. Patricia Marmol
  2. Favio Krapacher
  3. Carlos F Ibáñez  Is a corresponding author
  1. Department of Neuroscience, Karolinska Institute, Sweden
  2. Department of Physiology, National University of Singapore, Singapore
  3. Life Sciences Institute, National University of Singapore, Singapore
  4. Stellenbosch Institute for Advanced Study, Wallenberg Research Centre at Stellenbosch University, South Africa
6 figures and 3 additional files

Figures

Figure 1 with 2 supplements
Reduced iBAT mass in Ucp1CRE:Alk7fx/fx conditional mutant mice after fasting.

(A) Q-PCR determination of Acvr1c mRNA expression in hypothalamus (Hyp), interscapular BAT (iBAT), inguinal WAT (iWAT), epididymal WAT (eWAT) and liver of wild type mice. The values were normalized …

Figure 1—figure supplement 1
Normal energy consumption and food intake in mutant mice lacking ALK7 in BAT.

(A, B) VO2 and RER measured by indirect calorimetry at room temperature in 2 month old mice. RER values close to unit indicate carbohydrate usage, while values around 0.7 indicate fat consumption. …

Figure 1—figure supplement 2
Normal BAT differentiation in mice lacking ALK7 in brown adipocytes.

(A) mRNA expression of differentiation and maturation markers in BAT of 2 month old control (Alk7fx/fx) and mutant (Ucp1CRE:Alk7fx/fx) mice assessed by Q-PCR. Values are expressed relative to levels …

Figure 2 with 2 supplements
Fasting induces abnormally increased fat catabolism in BAT of Ucp1CRE:Alk7fx/fx conditional mutant mice.

(A) Representative BODIPY 493/503 staining of iBAT sections of conditional mutant (Ucp1CRE:Alk7fx/fx) and control (Alk7fx/fx) mice. Scale bar, 20 µm. Histograms to the right show quantitative …

Figure 2—figure supplement 1
Reduced lipid droplets in iBAT from Alk7 knock-out mice, unchanged levels of ATGL protein in fasted wild type mice, and normal Adrb1 and Adrb3 mRNA levels in iBAT lacking ALK7.

(A) Representative BODIPY 493/503 staining of iBAT sections of global Alk7-/- knock out mice and wild type controls. Scale bar, 20 µm. Histogram to the right show quantitative analysis of lipid …

Figure 2—figure supplement 2
Normal P-AKT levels and insulin sensitivity in iBAT lacking ALK7.

(A) Phospho-AKTS473 in BAT of control (Alk7fx/fx) and mutant (Ucp1CRE:Alk7fx/fx) 2 month old mice fed on Chow ad libitum (Ad lib) or fasted for 14 hr, assessed by western blotting of BAT lysates. …

Figure 3 with 1 supplement
Abnormally enhanced amino acid catabolism upon nutrient stress in iBAT lacking ALK7.

(A, B) Q-PCR determination of Prodh (A) and Alt1 and Bcat2 (B) mRNA expression in iBAT of 2 month old conditional mutant and control mice fed Chow ad libitum or after 14 hr fasting. The values were …

Figure 3—figure supplement 1
Microarray analysis of genes differentially expressed in iBAT of Alk7-/- global knock-out mice compared to wild type.

(A) Heat map showing relative expression of mRNAs differentially expressed (p<0.05) in iBAT of Alk7-/- global knock-out mice relative to wild type controls. The animals (N = 4 per group) were kept …

Figure 4 with 1 supplement
Activin B suppresses expression of mRNAs encoding KLF15 and amino acid degrading enzymes in isolated mouse and human brown adipocytes.

(A) Q-PCR determination of Klf15, Prodh, Alt1 and Bcat2 mRNA expression in primary cultures of differentiated (d10) compared to non-differentiated (d0) brown adipocytes isolated from iBAT of wild …

Figure 4—figure supplement 1
Effect of activin B on mRNA expression of BAT markers Ucp1 and Prdm16 assessed in cultured brown adipocytes.

Relative levels of Ucp1 and Prdm16 mRNAs were assessed by Q-PCR after 24hstimulation with activin B in the presence or absence of SB431542 inhibitor as indicated. Values were normalized to control …

Figure 5 with 2 supplements
Increased proline-dependent ATP generation in mitochondria from iBAT lacking ALK7.

(A) Western blot analysis of proline dehydrogenase (POX) and succinate dehydrogenase CII subunit (SDHA-CII) in iBAT of 2 month old conditional mutant and control mice fed Chow ad libitum (top) or …

Figure 5—figure supplement 1
Expression of mitochondrial proteins in BAT of control and conditional mutant mice fed ad libitum or after 14 hr fasting.

(A, B) Expression of UCP1, COXIV, Rieske FeS, NDUFA10 and beta F1 ATPase (BATP) in BAT of control (Alk7fx/fx) and mutant (Ucp1CRE:Alk7fx/fx) 2 month old mice fed on Chow ad libitum (Ad lib) (A) or …

Figure 5—figure supplement 2
Control experiments for measurements of ROS and ATP production.

(A) ROS production in BAT mitochondria from wild type mice induced by rotenone and proline (arrow). N=3 independent mitochondrial preparations. (B) ATP generation in liver mitochondria from fasted …

Figure 6 with 5 supplements
Fasting-induced hypothermia in mice lacking ALK7 in brown adipocytes.

(A, D) VO2 measured by indirect calorimetry in ad libitum fed (A) or 14h-fasted (D) 2 month old conditional mutant and control mice during exposure to 5°C in metabolic cages. N = 5 (A) and 10–12 (D) …

Figure 6—figure supplement 1
Influence of fasting and cold exposure on levels of glucose, insulin, activity, free-fatty acids, triglycerides and body temperature.

(A, B) Activity in metabolic chambers of mice during exposure at 5°C preceded by ad libitum feeding (panel A, N = 5 mice per genotype) or after 14 hr fasting (panel B, N = 10 mice per genotype). (C) …

Figure 6—figure supplement 2
Unchanged norepinephrine signaling in iBAT of Ucp1CRE:Alk7fx/fx mutant mice after fasting and acute cold exposure.

(A) Norepinephrine (NE) turnover in iBAT. After 14 hr fasting (t = 0), mice were injected with α-Methyl-DL-tyrosine methyl ester hydrochloride (AMT) and placed at 5° for 3 hr, after which NE was …

Figure 6—figure supplement 3
Body weight, food intake and Ucp1 mRNA levels after chronic cold exposure (21 d at 10°C) in control and mutant mice.

(A) Body weight. RT, room temperature. Shown are averages ± SEM. N = 5 mice per group. (B) Daily food intake. Shown are averages ± SEM. N = 5 mice per group. (C) Levels of Ucp1 mRNA in iBAT assessed …

Figure 6—figure supplement 4
Expression of mRNA levels encoding thermogenic markers in inguinal WAT after chronic cold exposure (21 d at 10°C) in control and conditional mutant mice.

(A to E) Levels of Ucp1, Cidea, Pparα, Pgc1α and Prdm16 mRNAs in inguinal WAT assessed by Q-PCR in mice kept at room temperature and after chronic cold exposure. Shown are averages relative to …

Figure 6—figure supplement 5
Schematic model for possible signaling pathway related to the role of ALK7 in mediating BAT responses to nutrient stress.

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