Tributyltin differentially promotes development of a phenotypically distinct adipocyte

Area of Science:

• Environmental health
• Endocrinology
• Cell biology

Background:

• Environmental endocrine disrupting chemicals (EDCs) are linked to obesity development.
• Tributyltin (TBT) is a proadipogenic EDC that activates peroxisome proliferator activated receptor-γ (PPARγ).
• The precise conditions and functional outcomes of TBT-induced adipogenesis require further investigation.

Purpose of the Study:

• To compare the costimulatory requirements for TBT-induced adipogenesis with a known PPARγ agonist, troglitazone (Trog).
• To assess the functional consequences of TBT-induced adipogenesis, including glucose uptake and adipocyte-specific gene and protein expression.
• To elucidate the distinct mechanisms by which EDCs like TBT influence adipocyte differentiation and function.

Main Methods:

• Utilized the 3T3-L1 cell line to compare TBT and troglitazone (Trog) in inducing preadipocyte-to-adipocyte differentiation.
• Assessed basal and insulin-stimulated glucose uptake using radiolabeled 2-deoxyglucose.
• Analyzed adipocyte-specific gene and protein expression, including C/EBPα and adiponectin.

Main Results:

• TBT induced adipocyte differentiation marker C/EBPα expression with co-stimuli like insulin or isobutylmethylxanthine.
• TBT and Trog differentially regulated adipocyte-specific protein expression despite similar PPARγ activation.
• TBT reduced adiponectin expression and altered glucose metabolism, increasing basal glucose uptake in differentiated adipocytes.

Conclusions:

• TBT-induced adipocytes exhibit distinct functional characteristics compared to those differentiated by pharmacological PPARγ agonists.
• Obesogen-induced adipogenesis may lead to the development of dysfunctional adipocytes.
• These dysfunctional adipocytes have the potential to negatively impact overall energy homeostasis.