Reduced intestinal lipid absorption improves glucose metabolism in aged G2-Terc knockout mice.

BACKGROUND: Biological aging is an important factor leading to the development of pathologies associated with metabolic dysregulation, including type 2 diabetes, cancer, cardiovascular and neurodegenerative diseases. Telomere length, a central feature of aging, has additionally been identified as inversely associated with glucose tolerance and the development of type 2 diabetes. However, the effects of shortened telomeres on body weight and metabolism remain incompletely understood. Here, we studied the metabolic consequences of moderate telomere shortening using second generation loss of telomerase activity in mice. RESULTS: Aged male and female G2 Terc-/- mice and controls were characterized with respect to body weight and composition, glucose homeostasis, insulin sensitivity and metabolic activity. This was complemented with molecular and histological analysis of adipose tissue, liver and the intestine as well as microbiota analysis. We show that moderate telomere shortening leads to improved insulin sensitivity and glucose tolerance in aged male and female G2 Terc-/- mice. This is accompanied by reduced fat and lean mass in both sexes. Mechanistically, the metabolic improvement results from reduced dietary lipid uptake in the intestine, characterized by reduced gene expression of fatty acid transporters in enterocytes of the small intestine. Furthermore, G2-Terc-/- mice showed significant alterations in the composition of gut microbiota, potentially contributing to the improved glucose metabolism. CONCLUSIONS: Our study shows that moderate telomere shortening reduces intestinal lipid absorption, resulting in reduced adiposity and improved glucose metabolism in aged mice. These findings will guide future murine and human aging studies and provide important insights into the age associated development of type 2 diabetes and metabolic syndrome.

Immune Cell Regulation of White Adipose Progenitor Cell Fate.

Adipose tissue is essential for energy storage and endocrine regulation of metabolism. Imbalance in energy intake and expenditure result in obesity causing adipose tissue dysfunction. This alters cellular composition of the stromal cell populations and their function. Moreover, the individual cellular composition of each adipose tissue depot, regulated by environmental factors and genetics, determines the ability of the depots to expand and maintain its endocrine and storage function. Thus, stromal cells modulate adipocyte function and vice versa. In this mini-review we discuss heterogeneity in terms of composition and fate of adipose progenitor subtypes and their interactions with and regulation by different immune cell populations. Immune cells are the most diverse cell populations in adipose tissue and play essential roles in regulating adipose tissue function via interaction with adipocytes but also with adipocyte progenitors. We specifically discuss the role of macrophages, mast cells, innate lymphoid cells and T cells in the regulation of adipocyte progenitor proliferation, differentiation and lineage commitment. Understanding the factors and cellular interactions regulating preadipocyte expansion and fate decision will allow the identification of novel mechanisms and therapeutic strategies to promote healthy adipose tissue expansion without systemic metabolic impairment.

Amplification of Oxidative Stress in MCF-7 Cells by a Novel pH-Responsive Amphiphilic Micellar System Enhances Anticancer Therapy.

The excessive increase of intracellular reactive oxygen species (ROS) makes tumor cells usually in the state of oxidative stress. Although tumor cells can adapt to this state to a certain extent by upregulating antioxidant systems, the further ROS insults disrupt the transient intracellular redox balance, eventually leading to apoptosis and necrosis. Therefore, increasing the intracellular ROS level can effectively amplify the oxidative stress and induce apoptosis, which can be employed as a strategy for tumor treatment. Herein, a unique pH-responsive ROS inducing micellar system was reported in this study to specifically amplify the ROS signal in tumor cells. This micellar system was constructed by a new amphiphilic polymer, PIAThydCA, composed of poly(itaconic acid) (PIA) as the hydrophilic backbone, d-α-tocopherol polyethylene glycol 1000 succinate (TPGS) as the hydrophobic side chain, and cinnamaldehyde (CA) as the ROS-generating agent, which were linked to PIA by the pH-sensitive hydrazone bond. PIAThydCA micelles could be degraded in the intracellular acidic environment through the hydrolysis of hydrazone bond and release CA. CA and TPGS could amplify oxidative stress cooperatively to kill MCF-7 human breast cells preferentially through the mitochondrial apoptosis pathway. Therefore, we anticipate that the PIAThydCA micelles could exert great potential in anticancer therapy.