Biology subjects

Simmons, R. A.

Publications and source records attributed to Simmons, R. A..

4 recordsLinked to original sources

bioRxiv2026

Perinatal Semaglutide Treatment Improves Maternal Health and Mitigates Offspring Metabolic Dysfunction in a Mouse Model of Maternal Obesity

Early-life exposures during critical periods of development significantly impact lifelong metabolic risk and likely contribute to the rising rates of obesity, type 2 diabetes, and metabolic dysfunction-associated steatotic liver disease (MASLD) in children. Here, we evaluated the safety and metabolic effects of semaglutide, a GLP-1 receptor agonist (GLP-1 RA), administered from preconception through lactation in dams fed a high-fat diet (HFD) or standard diet, and assessed metabolic outcomes in dams and their offspring. Offspring were weaned to a standard diet. We found that semaglutide improved body composition and glucose metabolism in HFD-fed dams during pregnancy. These maternal changes persisted 10 weeks after weaning despite discontinuation of semaglutide treatment. HFD exposure impaired glucose homeostasis and promoted hepatic steatosis in offspring at 18 weeks. These effects were ameliorated by maternal semaglutide treatment. Importantly, metabolic improvements in dams and offspring occurred without adverse effects on conception rate or fetal viability. These findings suggest that GLP-1 RA during the perinatal period can improve maternal and offspring metabolic health in a mouse model of obesity and support further investigation of GLP-1-based therapies to mitigate maternal metabolic dysfunction and improve metabolic risk in children. ARTICLE HIGHLIGHTS* Rates of obesity, type 2 diabetes, and fatty liver disease are rising in children, in part due to maternal obesity and insulin resistance that program offspring metabolic risk during the perinatal period. * We asked whether the GLP-1 receptor agonist (GLP-1 RA), semaglutide, administered during critical developmental windows could prevent adverse outcomes in offspring using a diet-induced mouse model of maternal obesity. * Semaglutide, given to dams from preconception through lactation, improved maternal metabolism and ameliorated metabolic dysfunction in offspring caused by maternal high-fat diet. * These findings highlight a potential role for perinatal GLP-1 receptor agonism to improve maternal metabolic health and reduce metabolic risk in offspring.

physiology↗

bioRxiv2025

Maternal exercise rescues fetal akinesia-impaired joint and bone development

Fetal movements exert mechanical forces that shape the developing skeleton. Conditions that impair fetal movements can cause skeletal defects, but interventions are limited. Here, we show that maternal wheel running exercise regulates fetal skeletal development in mice. In wild-type fetuses, maternal exercise stimulated joint and bone morphogenesis. We reasoned that these effects occurred through either indirect maternofetal communication or direct mechanical stimulation of the fetus. Maternal exercise did not alter placental measures of nutrient transport. However, in the Splotch-delayed (Spd) mouse model of fetal akinesia, which features intact maternofetal communication but lacks fetal movements, maternal exercise substantially rescued fetal akinesia-impaired joint and bone development and prevented disuse-induced resorption of the deltoid tuberosity. Further, direct mechanical stimulation of Spd limbs explanted from systemic factors similarly stimulated joint morphogenesis. Together, these findings identify maternal exercise as a regulator of fetal skeletal development, providing a platform for studying skeletal developmental mechanobiology and suggesting potential therapeutic applications for fetuses with impaired movement.

developmental biology↗

bioRxiv2024

The effect of intrauterine growth restriction on the developing pancreatic immune system

Immune cells in the pancreas are known to participate in organ development. However, the resident pancreatic immune system has yet to be fully defined. Immune cells also play a role in pathology and are implicated in diseases such as diabetes induced by intrauterine growth restriction (IUGR). We hypothesized that the resident immune system is established during neonatal development and disrupted by IUGR. Using single cell RNAseq and flow cytometry we identified many immune cell populations in the near-term fetus (at embryologic day 22) and neonatal (postnatal day 1, 7, &14) islets, non-endocrine pancreas, and the spleen in the rat. Using flow cytometry, we observed the resident immune system is established during neonatal development in the pancreas and spleen. We identified 9 distinct immune populations in the pancreatic islets and 8 distinct immune populations in the spleen by single cell RNAseq. There were no sex-specific differences in the relative proportion of immune cells in the pancreas or spleen. Finally, we tested if IUGR disrupted the neonatal immune system using bilateral uterine artery ligation. We found significant changes to the percentage of CD11B+ HIS48- and CD8+ T cells in the islets and non-endocrine pancreas and in the spleen. IUGR-induced alterations were influenced by the tissue environment and the sex of the offspring. Future research to define the role of these immune cells in pancreatic development may identify disrupted pathways that contribute to the development of diabetes following IUGR.

immunology↗

bioRxiv2024

COVID-19 during pregnancy alters circulating extracellular vesicle cargo and their effects on trophoblast

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and resulting coronavirus disease (COVID-19) causes placental dysfunction, which increases the risk of adverse pregnancy outcomes. While abnormal placental pathology resulting from COVID-19 is common, direct infection of the placenta is rare. This suggests that pathophysiology associated with maternal COVID-19, rather than direct placental infection, is responsible for placental dysfunction and alteration of the placental transcriptome. We hypothesized that maternal circulating extracellular vesicles (EVs), altered by COVID-19 during pregnancy, contribute to placental dysfunction. To examine this hypothesis, we characterized maternal circulating EVs from pregnancies complicated by COVID-19 and tested their effects on trophoblast cell physiology in vitro. We found that the gestational timing of COVID-19 is a major determinant of circulating EV function and cargo. In vitro trophoblast exposure to EVs isolated from patients with an active infection at the time of delivery, but not EVs isolated from Controls, altered key trophoblast functions including hormone production and invasion. Thus, circulating EVs from participants with an active infection, both symptomatic and asymptomatic cases, can disrupt vital trophoblast functions. EV cargo differed between participants with COVID-19 and Controls, which may contribute to the disruption of the placental transcriptome and morphology. Our findings show that COVID-19 can have effects throughout pregnancy on circulating EVs and circulating EVs are likely to participate in placental dysfunction induced by COVID-19.

pathology↗