TY - JOUR TI - ApoA1 Deficiency Reshapes the Phenotypic and Molecular Characteristics of Bone Marrow Adipocytes in Mice AU - Kastrenopoulou, A. AU - Kypreos, K.E. AU - Papachristou, N.I. AU - Georgopoulos, S. AU - Mastora, I. AU - Papadimitriou-olivgeri, I. AU - Spentzopoulou, A. AU - Nikitovic, D. AU - Kontogeorgakos, V. AU - Blair, H.C. AU - Papachristou, D.J. JO - International Journal of Molecular Sciences PY - 2022 VL - 23 TODO - 9 SP - null PB - MDPI SN - 1422-0067 TODO - 10.3390/ijms23094834 TODO - null TODO - In the present study, we studied the effect of apolipoprotein A-1 (APOA1) on the spatial and molecular characteristics of bone marrow adipocytes, using well-characterized ApoA1 knockout mice. APOA1 is a central regulator of high-density lipoprotein cholesterol (HDL-C) metabolism, and thus HDL; our recent work showed that deficiency of APOA1 increases bone marrow adiposity in mice. We found that ApoA1 deficient mice have greatly elevated adipocytes within their bone marrow compared to wild type counterparts. Morphologically, the increased adipocytes were sim-ilar to white adipocytes, and displayed proximal tibial-end localization. Marrow adipocytes from wild type mice were significantly fewer and did not display a bone-end distribution pattern. The mRNA levels of the brown/beige adipocyte-specific markers Ucp1, Dio2, Pat2, and Pgc1a; and the expression of leptin were greatly reduced in the ApoA1 knock-out in comparison to the wild-type mice. In the knock-out mice, adiponectin was remarkably elevated. In keeping with the close ties of hematopoietic stem cells and marrow adipocytes, using flow cytometry we found that the elevated adiposity in the ApoA1 knockout mice is associated with a significant reduction in the compartments of hematopoietic stem cells and common myeloid, but not of the common lymphoid, progenitors. Moreover, the ‘beiging’-related marker osteopontin and the angiogenic factor VEGF were also reduced in the ApoA1 knock-out mice, further supporting the notion that APOA1—and most proba-bly HDL-C—regulate bone marrow microenvironment, favoring beige/brown adipocyte character-istics. © 2022 by the author. Licensee MDPI, Basel, Switzerland. ER -