281 - Sex-Differences in Offspring Hematopoietic Stem Cell Function in Offspring of Obese Dams

Poster Number: 281
Publication Number: 281.119

Merve Denizli, Indiana University School of Medicine, Fishers, IN, United States; Abigail L. Toren, Indiana University School of Medicine, Indianapolis, IN, United States; Laura Haneline, Indiana University School of Medicine, Indianapolis, IN, United States; Maegan Capitano, Indiana University School of Medicine, Indianapolis, IN, United States; Kok Lim Kua, Indiana University School of Medicine, Indianapolis, IN, United States

Background: Children born to mothers with obesity are at higher risk of developing cardiometabolic diseases and obesity. While it is known that obesity increases inflammation and impacts hematopoietic stem cell (HSC) function in adults, the role of maternal obesity exposure on offspring HSC function is understudied. Using a diet-induced maternal obesity model, we previously reported that both male and female offspring born to obese dams had higher adiposity as well as sex differences in glucose intolerance.

Objective: We hypothesize that offspring of obese mice have decreased HSC function.

Design/Methods: Female dams were fed with chow (Con) or western diet (MatOb) for four weeks prior to mating, through pregnancy and the lactating period. Bone marrow was collected from offspring on postnatal day 21 (P21) or at 8 weeks of age (8W) after weaning to regular chow. Flow analysis was performed on lineage depleted bone marrow cells stained with c-Kit, Sca-1, CD34, Flt3, CD16/32, IL-7ra, CD3, B220, Gr-1, Mac1. Competitive repopulation assay was performed using LSK (Lin- Sca-1+ cKit+) enriched cells from P21 pups as donor cells. Donor chimerism was analyzed at 4- and 16-weeks post-primary and secondary transplants as a measure of HSC function.

Results: At P21, MatOb offspring had lower long-term (LT)-HSC (LSK CD34- Flt3-) and unchanged multipotent progenitor (MPP; LSK CD34+ Flt3+). At 8 weeks, while there was no difference in LT-HSC, male offspring had an increase in MPP, common myeloid (Lin- Sca-1- cKit+ [LK] CD34int CD16/32lo), granulocyte-macrophage (LK CD34hi CD16/32hi), and megakaryocyte-erythrocyte progenitors (LK CD34-/lo CD16/32-/lo), suggesting that male MatOb offspring have a myeloid shift. The competitive repopulation assay revealed that LSK-enriched cells from male MatOb pups had higher donor chimerism 16 weeks following primary transplantation compared to male Con pups, while donor chimerism of LSK-enriched cells from female pups was unchanged. Following secondary transplant, recipient mice transplanted with male MatOb donor cells had significantly lower donor chimerism at 4 and 16 weeks, and lower donor LT-HSC in the bone marrow at 16 weeks. (All data had n of ≥5 mice from ≥3 litters/group).Conclusion(s): Together these data demonstrate that male MatOb offspring have altered HSC function, while female MatOb offspring HSC function was unaffected. The observed myeloid shift in male MatOb offspring warrants further investigation into the role of inflammation in mediating HSC dysfunction.