Myostatin Attenuation In Vivo Reduces Adiposity, but Activates Adipogenesis

Abstract A potentially novel approach for treating obesity includes attenuating myostatin as this increases muscle mass and decreases fat mass. Notwithstanding, conflicting studies report that myostatin stimulates or inhibits adipogenesis and it is unknown whether reduced adiposity with myostatin attenuation results from changes in fat deposition or adipogenesis. We therefore quantified changes in the stem, transit amplifying and progenitor cell pool in white adipose tissue (WAT) and brown adipose tissue (BAT) using label-retaining wild-type and mstn−/− (Jekyll) mice. Muscle mass was larger in Jekyll mice, WAT and BAT mass was smaller and label induction was equal in all tissues from both wild-type and Jekyll mice. The number of label-retaining cells, however, dissipated quicker in WAT and BAT of Jekyll mice and was only 25% and 17%, respectively, of wild-type cell counts 1 month after induction. Adipose cell density was significantly higher in Jekyll mice and increased over time concomitant with label-retaining cell disappearance, which is consistent with enhanced expansion and differentiation of the stem, transit amplifying and progenitor pool. Stromal vascular cells from Jekyll WAT and BAT differentiated into mature adipocytes at a faster rate than wild-type cells and although Jekyll WAT cells also proliferated quicker in vitro, those from BAT did not. Differentiation marker expression in vitro, however, suggests that mstn−/− BAT preadipocytes are far more sensitive to the suppressive effects of myostatin. These results suggest that myostatin attenuation stimulates adipogenesis in vivo and that the reduced adiposity in mstn−/− animals results from nutrient partitioning away from fat and in support of muscle.

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TAF7L modulates brown adipose tissue formation

eLife ◽

10.7554/elife.02811 ◽

2014 ◽

Vol 3 ◽

Cited By ~ 12

Author(s):

Haiying Zhou ◽

Bo Wan ◽

Ivan Grubisic ◽

Tommy Kaplan ◽

Robert Tjian

Keyword(s):

Adipose Tissue ◽

Brown Adipose Tissue ◽

Core Promoter ◽

Uncoupling Protein ◽

Dna Looping ◽

Chromatin Interactions ◽

Brown Adipose ◽

Important Regulator

Brown adipose tissue (BAT) plays an essential role in metabolic homeostasis by dissipating energy via thermogenesis through uncoupling protein 1 (UCP1). Previously, we reported that the TATA-binding protein associated factor 7L (TAF7L) is an important regulator of white adipose tissue (WAT) differentiation. In this study, we show that TAF7L also serves as a molecular switch between brown fat and muscle lineages in vivo and in vitro. In adipose tissue, TAF7L-containing TFIID complexes associate with PPARγ to mediate DNA looping between distal enhancers and core promoter elements. Our findings suggest that the presence of the tissue-specific TAF7L subunit in TFIID functions to promote long-range chromatin interactions during BAT lineage specification.

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JAZF1 heterozygous knockout mice show altered adipose development and metabolism

Cell & Bioscience ◽

10.1186/s13578-021-00625-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Jain Jeong ◽

Soyoung Jang ◽

Song Park ◽

Wookbong Kwon ◽

Si-Yong Kim ◽

...

Keyword(s):

Adipose Tissue ◽

Knockout Mice ◽

Metabolic Disorders ◽

Adipocyte Differentiation ◽

Zinc Finger Protein ◽

Tissue Mass ◽

In Vivo Models ◽

Brown Adipose

Abstract Background Juxtaposed with another zinc finger protein 1 (JAZF1) is associated with metabolic disorders, including type 2 diabetes mellitus (T2DM). Several studies showed that JAZF1 and body fat mass are closely related. We attempted to elucidate the JAZF1 functions on adipose development and related metabolism using in vitro and in vivo models. Results The JAZF1 expression was precisely regulated during adipocyte differentiation of 3T3-L1 preadipocyte and mouse embryonic fibroblasts (MEFs). Homozygous JAZF1 deletion (JAZF1-KO) resulted in impaired adipocyte differentiation in MEF. The JAZF1 role in adipocyte differentiation was demonstrated by the regulation of PPARγ—a key regulator of adipocyte differentiation. Heterozygous JAZF1 deletion (JAZF1-Het) mice fed a normal diet (ND) or a high-fat diet (HFD) had less adipose tissue mass and impaired glucose homeostasis than the control (JAZF1-Cont) mice. However, other metabolic organs, such as brown adipose tissue and liver, were negligible effect on JAZF1 deficiency. Conclusion Our findings emphasized the JAZF1 role in adipocyte differentiation and related metabolism through the heterozygous knockout mice. This study provides new insights into the JAZF1 function in adipose development and metabolism, informing strategies for treating obesity and related metabolic disorders.

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Developmental aspects of adipose tissue in GH receptor and prolactin receptor gene disrupted mice: site-specific effects upon proliferation, differentiation and hormone sensitivity

Journal of Endocrinology ◽

10.1677/joe.1.06939 ◽

2006 ◽

Vol 191 (1) ◽

pp. 101-111 ◽

Cited By ~ 39

Author(s):

David J Flint ◽

Nadine Binart ◽

Stephanie Boumard ◽

John J Kopchick ◽

Paul Kelly

Keyword(s):

Adipose Tissue ◽

Receptor Gene ◽

Metabolic Effects ◽

Wild Type ◽

Extrinsic Factors ◽

Differentiation Potential ◽

Site Specific ◽

Proliferation And Differentiation

Direct metabolic effects of GH on adipose tissue are well established, but effects of prolactin (PRL) have been more controversial. Recent studies have demonstrated PRL receptors on adipocytes and effects of PRL on adipose tissue in vitro. The role of GH in adipocyte proliferation and differentiation is also controversial, since GH stimulates adipocyte differentiation in cell lines, whereas it stimulates proliferation but inhibits differentiation of adipocytes in primary cell culture. Using female gene disrupted (ko) mice, we showed that absence of PRL receptors (PRLRko) impaired development of both internal and s.c. adipose tissue, due to reduced numbers of adipocytes, an effect differing from that of reduced food intake, where cell volume is decreased. In contrast, GHRko mice exhibited major decreases in the number of internal adipocytes, whereas s.c. adipocyte numbers were increased, even though body weight was decreased by 40–50%. The changes in adipose tissue in PRLRko mice appeared to be entirely due to extrinsic factors since preadipocytes proliferated and differentiated in similar fashion to wild-type animals in vitro and their response to insulin and isoproterenol was similar to wild-type animals. This contrasted with GHRko mice, where s.c. adipocytes proliferated, differentiated, and responded to hormones in identical fashion to controls, whereas parametrial adipocytes exhibited markedly depressed proliferation and differentiation potential and failed to respond to insulin or noradrenaline. Our results provide in vivo evidence that both GH and PRL stimulate differentiation of adipocytes but that the effects of GH are site specific and induce intrinsic changes in the precursor population, which are retained in vitro.

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Dopamine receptor D1- and D2-agonists do not spark brown adipose tissue thermogenesis in mice

Scientific Reports ◽

10.1038/s41598-020-77143-6 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Francesca-Maria Raffaelli ◽

Julia Resch ◽

Rebecca Oelkrug ◽

K. Alexander Iwen ◽

Jens Mittag

Keyword(s):

Adipose Tissue ◽

Brown Adipose Tissue ◽

Dopamine Receptor ◽

Ex Vivo ◽

Potential Target ◽

D2 Agonist ◽

Obesity And Diabetes ◽

Brown Adipose

AbstractBrown adipose tissue (BAT) thermogenesis is considered a potential target for treatment of obesity and diabetes. In vitro data suggest dopamine receptor signaling as a promising approach; however, the biological relevance of dopamine receptors in the direct activation of BAT thermogenesis in vivo remains unclear. We investigated BAT thermogenesis in vivo in mice using peripheral administration of D1-agonist SKF38393 or D2-agonist Sumanirole, infrared thermography, and in-depth molecular analyses of potential target tissues; and ex vivo in BAT explants to identify direct effects on key thermogenic markers. Acute in vivo treatment with the D1- or D2-agonist caused a short spike or brief decrease in BAT temperature, respectively. However, repeated daily administration did not induce lasting effects on BAT thermogenesis. Likewise, neither agonist directly affected Ucp1 or Dio2 mRNA expression in BAT explants. Taken together, the investigated agonists do not seem to exert lasting and physiologically relevant effects on BAT thermogenesis after peripheral administration, demonstrating that D1- and D2-receptors in iBAT are unlikely to constitute targets for obesity treatment via BAT activation.

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PPARγ regulates adipose triglyceride lipase in adipocytes in vitro and in vivo

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00122.2007 ◽

2007 ◽

Vol 293 (6) ◽

pp. E1736-E1745 ◽

Cited By ~ 132

Author(s):

Erin E. Kershaw ◽

Michael Schupp ◽

Hong-Ping Guan ◽

Noah P. Gardner ◽

Mitchell A. Lazar ◽

...

Keyword(s):

Protein Synthesis ◽

Adipose Tissue ◽

Lipid Metabolism ◽

Protein Synthesis Inhibitor ◽

Adipose Triglyceride Lipase ◽

Dependent Manner ◽

Triglyceride Lipase ◽

Brown Adipose

Peroxisome proliferator-activated receptor-γ (PPARγ) regulates adipocyte genes involved in adipogenesis and lipid metabolism and is the molecular target for thiazolidinedione (TZD) antidiabetic agents. Adipose triglyceride lipase (ATGL) is a recently described triglyceride-specific lipase that is induced during adipogenesis and remains highly expressed in mature adipocytes. This study evaluates the ability of PPARγ to directly regulate ATGL expression in adipocytes in vitro and in vivo. In fully differentiated 3T3-L1 adipocytes, ATGL mRNA and protein are increased by TZD and non-TZD PPARγ agonists in a dose- and time-dependent manner. Rosiglitazone-mediated induction of ATGL mRNA is rapid and is not inhibited by the protein synthesis inhibitor cycloheximide, indicating that intervening protein synthesis is not required for this effect. Rosiglitazone-mediated induction of ATGL mRNA and protein is inhibited by the PPARγ-specific antagonist GW-9662 and is also significantly reduced following siRNA-mediated knockdown of PPARγ, supporting the direct transcriptional regulation of ATGL by PPARγ. In vivo, ATGL mRNA and protein are increased by rosiglitazone treatment in white and brown adipose tissue of mice with and without obesity due to high-fat diet or leptin deficiency. Thus, PPARγ positively regulates ATGL mRNA and protein expression in mature adipocytes in vitro and in adipose tissue in vivo, suggesting a role for ATGL in mediating PPARγ's effects on lipid metabolism.

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Effect of brown adipose tissue/cells on the growth of mouse hepatocellular carcinoma in�vitro and in�vivo

Oncology Letters ◽

10.3892/ol.2019.9977 ◽

2019 ◽

Author(s):

Dong Liu ◽

Yi Li ◽

Yue Shang ◽

Wendie Wang ◽

Shu‑Zhen Chen

Keyword(s):

Hepatocellular Carcinoma ◽

Adipose Tissue ◽

Brown Adipose Tissue ◽

Brown Adipose ◽

Tissue Cells ◽

Adipose Tissue Cells

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PI3K/Akt/FOXO3a Pathway Contributes to Thrombopoietin-Induced Proliferation of Primary Megakaryocytes In Vitro and In Vivo Via Modulation of p27Kip1.

Blood ◽

10.1182/blood.v106.11.202.202 ◽

2005 ◽

Vol 106 (11) ◽

pp. 202-202

Author(s):

Takafumi Nakao ◽

Amy E Geddis ◽

Norma E. Fox ◽

Kenneth Kaushansky

Keyword(s):

Cell Cycle ◽

Cell Line ◽

Cell Cycle Progression ◽

Wild Type ◽

Cycle Progression ◽

P27kip1 Expression ◽

Cell Counts ◽

Deficient Mice

Abstract Thrombopoietin (TPO), the primary regulator of megakaryocyte (MK) and platelet formation, modulates the activity of multiple signal transduction molecules, including those in the Jak/STAT, p42/p44 MAPK, and phosphatidylinositol 3-kinase (PI3K)/Akt pathways. In the previous study, we reported that PI3K and Akt are necessary for TPO-induced cell cycle progression of primary MK progenitors. The absence of PI3K activity results in a block of transition from G1 to S phase in these cells (Geddis AE et al. JBC2001276:34473–34479). However, the molecular events secondary to the activation of PI3K/Akt responsible for MK proliferation remain unclear. In this study we show that FOXO3a and its downstream target p27Kip1 play an important role in TPO-induced proliferation of MK progenitors. TPO induces phosphorylation of Akt and FOXO3a in both UT-7/TPO, a megakaryocytic cell line, and primary murine MKs in a PI3K dependent fashion. Cell cycle progression of UT-7/TPO cells is blocked in G1 phase by inhibition of PI3K. We found that TPO down-modulates p27Kip1 expression at both the mRNA and protein levels in UT-7/TPO cells and primary MKs in a PI3K dependent fashion. UT-7/TPO stably expressing constitutively active Akt or a dominant-negative form of FOXO3a failed to induce p27Kip1 expression after TPO withdrawal. Induced expression of an active form of FOXO3a resulted in increased p27Kip1 expression in this cell line. In an attempt to assess whether FOXO3a has an effect of MK proliferation in vivo, we compared the number of MKs in Foxo3a-deficient mice and in wild type controls. Although peripheral blood cell counts of erythrocytes, neutrophils, monocytes and platelets were normal in the Foxo3a-deficient mice, total nucleated marrow cell count of Foxo3a-deficient mice were 60% increased compared with wild type controls. In addition, the increase of MKs was more profound than that of total nucleated marrow cells; CD41+ MKs from Foxo3a-deficient mice increased 2.1-fold, and mature MKs with 8N and greater ploidy increased 2.5-fold, compared with wild type controls. Taken together with the previous observation that p27Kip1-deficient mice also display increased numbers of MK progenitors, our findings strongly suggest that the effect of TPO on MK proliferation is mediated by PI3K/Akt-induced FOXO3a inactivation and subsequent p27Kip1 down-regulation in vitro and in vivo.

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Expression of peroxisome proliferator-activated receptors in lean and obese Zucker rats

Acta Endocrinologica ◽

10.1530/eje.0.1420071 ◽

2000 ◽

pp. 71-78 ◽

Cited By ~ 29

Author(s):

A Gorla-Bajszczak ◽

C Siegrist-Kaiser ◽

O Boss ◽

AG Burger ◽

CA Meier

Keyword(s):

Adipose Tissue ◽

Fiber Type ◽

Zucker Rats ◽

Peroxisome Proliferator ◽

Mrna Levels ◽

Rnase Protection ◽

Brown Adipose ◽

Obese Zucker Rats

OBJECTIVE: Examination of the pattern of expression of peroxisome proliferator-activated receptor (PPAR) isoforms alpha and gamma in a model of obesity. DESIGN: Examination of adipose tissue and primary adipocyte cultures from lean and obese Zucker rats at different ages (28 days and 12 weeks). METHODS: mRNA levels were measured by RNase protection assay.RESULTS: The highest levels of PPARalpha and gamma mRNA were present in brown adipose tissue (BAT), followed by liver and white adipose tissue (WAT) for the alpha and gamma subtypes, respectively, at both ages examined. PPARalpha was expressed 100-fold higher in BAT compared with WAT, and PPARgamma mRNA levels were 2-fold higher in the WAT of obese compared with lean rats. PPARalpha and gamma expression was minimal in m. soleus, although higher levels of PPARgamma were found in the diaphragm. In marked contrast to the findings in vivo, virtually no PPARalpha mRNA could be detected in BAT cultures differentiated in vitro. CONCLUSION: PPARalpha and gamma are most highly expressed in BAT in vivo. However, PPARalpha is undetectable in brown adipose cells in vitro, suggesting that the expression of this receptor is induced by some external stimuli. In addition, the expression of PPARgamma was increased in WAT from young obese animals, compatible with an early adaptive phenomenon. Finally, the presence of PPARgamma mRNA is detectable only in particular muscles, such as the diaphragm, suggesting the possibility of an influence of fiber type on its expression, although exercise did not influence the expression of PPARgamma in other skeletal muscles.

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JAK2 V617F Mutation Induces a Myeloproliferative Disorder in Mice.

Blood ◽

10.1182/blood.v106.11.376.376 ◽

2005 ◽

Vol 106 (11) ◽

pp. 376-376

Author(s):

Thomas G.P. Bumm ◽

Collin Elsea ◽

Lisa G. Wood ◽

Daniel W. Sherbenou ◽

Ian J. Griswold ◽

...

Keyword(s):

Pearson Correlation ◽

Jak2 V617f ◽

Peripheral Blood Smear ◽

P Value ◽

Wild Type ◽

Empty Vector ◽

Cell Counts ◽

Prolonged Culture

Abstract Background: An activating mutation (V617F) in the JH2 domain of the Jak2 kinase is found in 74%–97% of patients with polycythemia vera (PV), 23%–57% of patients with essential thrombocythemia and 35%–57% of patients with idiopathic myelofibrosis. We studied the effects of this mutant in murine hematopoietic cells in vitro and in vivo. Materials and Methods: Murine wild type (Jak2-WT) and V617F mutant JAK2 (Jak2-V617F) were cloned into the MIGR1-IRES-GFP retroviral vector. BaF3 cells stably expressing mutant and wild type Jak2 were generated by electroporation followed by prolonged culture in IL-3 containing media and FACS selection for GFP-positive cells. Proliferation and viability assays were performed in graded concentrations of IL-3. Bone marrow from 5-FU treated Balb/c mice were infected with JAK2-V617F, JAK2-WT and empty vector retrovirus and injected into lethally irradiated recipients. The mice were monitored by observation and blood counts. Plasma levels of erythropoietin (EPO) were determined by ELISA on day 44 after transplantation. 1-way analysis of variance (ANOVA) was used to compare differences between cell line and hematologic parameters. The relationship between EPO levels and Hct/Hgb was analysed by Pearson correlation. Results: BaF3 cells expressing JAK2-V617F showed enhanced proliferation in response to murine IL-3 compared to cells expressing Jak2-WT (p<0.001) and parental cells (p= 0.009). Similarly, there was a trend for increased viability (p=0.071 vs. Jak-WT and p=0.059 vs. parental cells). Sudden complete IL-3 withdrawal induced >95% cell death, followed by outgrowth of IL-3-independent lines after 20 days. Mice transplanted with Jak2-V617F showed increased median hematocrit (Hct), hemoglobin (Hgb) and median corpuscular volume (MCV) compared to Jak2-WT and empty vector mice (table). There was a trend for increased white cell counts (WBC). Median EPO levels were 65 pg/ml in the Jak2-V617F mice compared to 88 pg/ml in the Jak2-WT and 131 pg/ml in the empty vector controls (p= 0.032). There was a significant correlation between EPO and Hct (p = 0.011, r = −0.677) and Hgb (p= 0.002, r= −0.770) across the three groups of mice. On day 44 post transplant one Jak2-V617F mouse developed trilineage MPD with a Hct of 56.8%, leukocytosis (22.6 x 103/ul) and thrombocytosis (1004 x 103/ul). The peripheral blood smear showed neutrophilia, elevated platelets and multiple nucleated red cells. Necropsy revealed hepatosplenomegaly. Conclusions: (i) JAK2-V617F induces hypersensitivity to IL-3 in BaF3 cells. Complete IL-3 independence was seen only after “crisis” and prolonged culture, suggesting additional mutations may be required. (ii) In a murine transduction-transplantation model JAK2-V617F induces MPD closely mimicking PV. Studies are in progress to determine whether additional phenotypes may be observed in a larger cohort of animals. JAK2-V617F (n= 4) JAK2- WT (n= 4) MIGR-1 vector-control (n= 5) P value (V617F vs. WT) P value (V617F vs. empty vector) Median blood parameters (range) in groups of mice 44 days after transplant Hct (%) 51.1 (44.6–56.8) 43.7 (42.8–45) 43.6 (40.4–45.2) P = 0.015 P= 0.011 Hgb (g/dl) 16.2 (14.6–17.6) 14.6 (14.2–15.4) 14.2 (13–15) P= 0.033 P= 0.010 MCV (fl) 49.5 (47–54) 46.2 (46–47) 46.2 (45–48) P= 0.041 P= 0.031 WBC (103/ul) 9.6 (3.8–22.6) 5.5 (3.6–9.4) 3.4 (2.2–4.6) ns P= 0.096 EPO (pg/ml) 65 (44–98) 88 (80–112) 131 (95–231) ns P= 0.032

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