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Page 62
Volume 9
Journal of Obesity & Weight Loss Therapy
ISSN: 2165-7904
JOINT EVENT
Childhood Obesity 2019
Diabetes Conference 2019
March 18-19, 2019
&
3
rd
World Congress on
Diabetes and Obesity
12
th
International Conferences on
Childhood Obesity and Nutrition
March 18-19, 2019 | Rome, Italy
Adipose tissue-resident macrophages (M2-like) regulates proliferation of white and beige progenitors
Nawaz A
University of Toyama, Japan
P
revious reports suggested that adipose tissue macrophages are involved in maintaining insulin sensitivity in
adipocytes along with improvement in metabolic genes. Nonetheless, it is largely unknown how depletion of
M2-like macrophages regulates insulin sensitivity and adipocyte progenitor (AP) proliferation. To understand the
role of M2-like macrophages in white adipose tissue (WAT), we generated CD206DTR mice based on transgenic
expression of diphtheria toxin receptor under the control of the CD206(+) promoter to specifically deplete CD206
M2-like macrophages. Partial depletion of CD206 M2-like macrophages resulted in the generation of smaller
adipocytes, upregulated expression of metabolically favorable genes and enhanced insulin sensitivity in both chow
and high-fat diet-fed CD206-reduced mice. In vivo and in vitro studies revealed that Tgf1, abundantly expressed
in CD206 M2-like macrophages, regulate AP differentiation and proliferation. Flow cytometry analysis revealed that
the number of APs was increased and cyclin gene expression levels in the AP fraction were up-regulated. To validate
this hypothesis, we generated genetically engineered mice in which CD206 specific Tgfβ1 was knocked out after
tamoxifen treatment. Increased number of APs and smaller adipocytes were observed in the CD206 specific Tgfβ1
knockout mice, suggesting that CD206 cell-specific deletion of Tgfβ1 resulted in the enhanced proliferation of AP.
Previous studies had shown that type 2 cytokines and M2 macrophages induce cold-induced browning in inguinal
WAT (ingWAT) by producing catecholamines. Exactly how the conditional and partial depletion of CD206 M2-
like macrophages regulates the cold-induced browning of ingWAT, however, remains unknown. We also examined
the role of CD206 M2-like macrophages in the cold-induced browning of WAT and found that partial depletion
of CD206 M2-like macrophages caused an increase in the number of beige progenitors and also enhanced their
proliferation in ingWAT in response to cold. Thus, we concluded that CD206 M2-like macrophages inhibit the
proliferation of white and beige progenitors.
Keywords:
Adipocyte progenitors, adipose tissue macrophages, beige adipocyte, insulin sensitivity.
J Obes Weight Loss Ther 2019, Volume 9
DOI: 10.4172/2165-7904-C1-091