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Biology subjects

Houck, J. A.

Publications and source records attributed to Houck, J. A..

2 recordsLinked to original sources

Adiponectin restores cholinergic vasodilation in resistance vessels from adult offspring exposed to maternal obesity in utero

Maternal obesity increases the risk of cardiovascular and metabolic disease in the offspring both during childhood and adult life. Pregnant women and mice with obesity have lower circulating levels of adiponectin (ADN) compared to lean controls. ADN is an adipokine involved in regulating energy metabolism, vascular function, and placental function. We hypothesized that offspring of obese mice have impaired resistance artery function, which can be prevented by restoration of normal circulating ADN levels in obese dams during late pregnancy. Adult female mice were fed either control or obesogenic diet and mated with control diet-fed males. Control dams received a continuous infusion of phosphate saline buffer (PBS) during late pregnancy whereas obese females received either PBS or ADN. After weaning, offspring were fed a control diet. Mesenteric arteries (MsA) were dissected from adult offspring and mounted in a wire myograph or fixed for histology. MsA responses to vasoconstrictors (phenylephrine and endothelin-1) were not different between infusion groups. However, the vasodilatory responses to acetylcholine were reduced in offspring from obese dams as compared to control-fed dams. ADN supplementation during pregnancy restored the cholinergic vasodilatory responses of resistance vessels in offspring from obese dams. These observations suggest that normalizing circulating adiponectin levels in pregnancies complicated by obesity prevents in utero programming of vascular dysfunction in the offspring.

developmental biology↗

Breast cancer endocrine therapy exhausts adipocyte progenitors promoting weight gain and glucose intolerance

Breast cancer survivors treated with anti-estrogen therapies report weight gain and have an elevated risk of type 2 diabetes. Here, we show that current tamoxifen use associated with larger breast adipocyte diameter only in women with a BMI >30 kg/m2. To understand the mechanisms behind these clinical findings, we investigated the impact of estrogen deprivation and tamoxifen in a relevant pre-clinical model of obesity. Specifically, mature female mice were housed at thermoneutrality and fed either a low-fat/low-sucrose (LFLS) or a high-fat/high-sucrose (HFHS) diet. Consistent with the high expression of Esr1 observed in single-cell RNA sequencing of mesenchymal stem cells from adipose tissue, endocrine therapies induced adipose accumulation and preadipocyte expansion, but resulted in adipocyte progenitor depletion only in the context of HFHS. Consequently, 7-week endocrine therapy supported adipocyte hypertrophy and was associated with hepatic steatosis, hyperinsulinemia, insulin resistance, and glucose intolerance, particularly in HFHS fed females. Metformin or pioglitazone, glucose lowering drugs used to treat diabetes, prevented the effects of tamoxifen but not estrogen deprivation on adipocyte size and insulin resistance in HFHS-fed mice. This translational study suggests that endocrine therapies act via ER to directly disrupt adipocyte progenitors and support adipocyte hypertrophy, leading to ectopic lipid deposition that may promote hyperinsulinemia, insulin resistance and type 2 diabetes. Interventions that target insulin action should be considered for some women receiving life-saving endocrine therapies for breast cancer.

physiology↗