Dileepan, M.; Ali, S. S.; Williams, L.; Anderson, M.; He, Y.; Abrahante, J. E.; Peters, S.; Wang, Y.; Hudson, E.; Soto-Palma, C.; Raval, A.; Rodriguez, F. M.; Thompson, E. L.; Kummerfeld, E.; Bernlohr, D. A.; Camell, C.; Aliferis, C.; Wang, J.; Nelson, A. C.; Robbins, P. D.; Niedernhofer, L. J.; Ikramuddin, S.

Abstract Obesity accelerates key hallmarks of biological aging in visceral adipose tissue (VAT), yet age-associated changes in cellular senescence against a background of sustained elevated adiposity remain poorly understood. To investigate these changes, we examined human omental VAT from younger (18-35 years), middle-aged (36-51 years), and older adults (52-75 years) with comparable BMI (40 {+/-}5 kg/m2) using a cross-sectional design. We integrated bulk and single- nucleus RNA sequencing (snRNA-seq), Visium HD spatial transcriptomics, and three complementary computational approaches for senescent cell (SnC) identification. VAT from older adults exhibited increased expression of senescence-associated markers, including CDKN2A (p16INK4a) and CDKN1A (p21CIP1), as well as enhanced fibro-inflammatory and tissue-remodeling programs. snRNA-seq revealed a non-linear age-associated pattern, with relatively modest differences between younger and middle-aged adults and more pronounced senescence- associated changes in older adults. SnCs were increased primarily in adipose stem/progenitor cells and mesothelium, which also emerged as major intercellular communication hubs. CellChat analyses identified SnCs of multiple lineages converging on shared outgoing signaling programs, implicating inflammatory, extracellular matrix-remodeling, and adipogenic regulatory pathways, including IL-1, IL-6, TGF-{beta}, and WNT signaling. These predicted interactions were accompanied by transcriptional programs involving HIF1A, NF-{kappa}B, SMADs, PRRX1, and TP53 in SnCs, as well as consistent upregulation of KDM6B a histone demethylase activating gene expression. Collectively, our findings suggest that aging drives the senescence program to a greater extent than obesity, potentiating tissue dysfunction through coordinated intercellular signaling mechanisms.