Activin a plays a critical role in proliferation and differentiation of human adipose progenitors
Authors: Christian Elabd
Tamara Tchkonia
Daniele Lacasa
Yasuhiro Takashima
James L Kirkland
G√©rard Ailhaud
Marcel Scheideler
Karine Cl√©ment
Marie Maumus
Virginie Bourlier
Zlatko Trajanoski
Tala Mohsen-Kanson
Anne Bouloumie
Mayoura Keophiphath
Brigitte Wdziekonski
Coralie Sengenes
Laure-Emmanuelle Zaragosi
Phi Villageois
Ez-Zoubir Amri
Christian Dani
Annie Ladoux
Journal: Diabetes (2010)
Discipline: CLINICAL MEDICINE
Keywords: adipose progenitors; activin A; adipogenesis; obesity; macrophages
Affiliations: UMR6543 Centre National de la Recherche Scientifique, Institute of Developmental Biology and Cancer, University of Nice Sophia-Antipolis, Nice, France.

Abstract:  Objective: Growth of white adipose tissue takes place in normal development and in obesity. A pool of adipose progenitors is responsible for the formation of new adipocytes and for the potential of this tissue to expand in response to chronic energy overload. However, factors controlling self-renewal of human adipose progenitors are largely unknown. We investigated the expression profile and the role of activin A in this process. Research design and methods: Expression of INHBA/activin A was investigated in three types of human adipose progenitors. We then analyzed at the molecular level the function of activin A during human adipogenesis. We finally investigated the status of activin A in adipose tissues of lean and obese subjects and analyzed macrophage-induced regulation of its expression. Results: INHBA/activin A is expressed by adipose progenitors from various fat depots, and its expression dramatically decreases as progenitors differentiate into adipocytes. Activin A regulates the number of undifferentiated progenitors. Sustained activation or inhibition of the activin A pathway impairs or promotes, respectively, adipocyte differentiation via the C/EBPŒ≤-LAP and Smad2 pathway in an autocrine/paracrine manner. Activin A is expressed at higher levels in adipose tissue of obese patients compared with the expression levels in lean subjects. Indeed, activin A levels in adipose progenitors are dramatically increased by factors secreted by macrophages derived from obese adipose tissue. Conclusions: Altogether, our data show that activin A plays a significant role in human adipogenesis. We propose a model in which macrophages that are located in adipose tissue regulate adipose progenitor self-renewal through activin A. 

Retracted: No

PubPeer comments:
 Brought to my attention by a concerned reader. This paper is one of a set of four papers that all appear to describe the same groups of subjects and experiments. In these papers, 5 groups of 22 subjects each were asked to do 10 min of sitting (Control group; C), walking (W), meditating (M), walking then meditating (WM), or meditating then walking (MW). Two papers describe all 5 groups, so 110 participants, while the other 2 papers describe the C group and two of the other groups. The four papers are: 1. Differential Experimental Effects of a Short Bout of Walking, Meditation, or Combination of Walking and Meditation on State Anxiety Among Young Adults Meghan K. Edwards, Simon Rosenbaum, and Paul D. Loprinzi American Journal of Health Promotion 2018, Vol. 32(4) 949-958; DOI: 10.1177 0890117117744913 First Published December 7, 2017 Groups: 5 groups of 22 subject each, 10 min of C W M WM MW Analysis: State Trait Anxiety Inventory questionnaire 2. Affective Responses to Acute Bouts of Aerobic Exercise, Mindfulness Meditation, and Combinations of Exercise and Meditation: A Randomized Controlled Intervention Meghan K. Edwards, Paul D. Loprinzi Psychological Reports 2019, Vol. 122(2) 465u2013484; DOI: 10.1177 0033294118755099 First Published January 25, 2018 Groups: 5 groups of 22 subject each, 10 min of C W M WM MW Analysis: Exercise Induced Feelings Inventory 3. Experimental effects of brief, single bouts of walking and meditation on mood profile in young adults Meghan K. Edwards, Paul D. Loprinzi Health Promotion Perspectives, 2018, 8(3), 171-178; DOI: 10.15171 hpp.2018.23 Received: 26 Apr. 2018 Accepted: 19 May 2018 ePublished: 7 July 2018 Groups: 3 groups of 22 subject each, 10 min of C W M Analysis: Profile of Moods States (POMS) questionnaire 4. Experimental Effects of Acute Exercise and Meditation on Parameters of Cognitive Function Meghan K. Edwards and Paul D. Loprinzi Journal of Clinical Medicine 2018, 7, 125; DOI: 10.3390 jcm7060125 Received: 2 May 2018; Accepted: 25 May 2018; Published: 29 May 2018 Groups: 3 groups of 22 subject each, 10 min of C WM MW Analysis: CogStateu2019s Identification Task and Set Shifting Task (computerized), Inquisit Stroop Task (computerized), Trail Making A and B (pen and paper), 2 listing tasks (pen and paper) All 4 papers appear to describe (subsets of) the same 5 participant groups, based on e.g. the average age, gender ratio, and BMI. Here are screenshots of the demographics of each of the four papers. The colored boxes are mine.   The four papers only differ in the types of questionnaires or tasks done by the participants at the end of the exercise. But given the identical demographics, it seems very likely that all four different sets of tasks were done at the same time by the same set of subjects. One could wonder if these four papers should not have been combined into one paper, since it was basically one study to investigate the effect of exercise and meditation on mood. Splitting up the results might serve the purpose of more published papers by the authors, but obscures the overall effect of the exercise and meditation on emotional state, as well as the large amount of questionnaires and tasks that each participant had to complete. This graph captures all of the results of the combined four papers into one screenshot. These figures could have easily been combined into one paper.  Could the authors please comment? ,