Obesity modulates NK cell activity via LDL and DUSP1 signaling for populations with adverse social determinants
Yvonne Baumer, Komudi Singh, Abhinav Saurabh, Andrew S. Baez, Cristhian A. Gutierrez-Huerta, Long Chen, Muna Igboko, Briana S. Turner, Josette A. Yeboah, Robert N. Reger, Lola R. Ortiz-Whittingham, Sahil Joshi, Marcus R. Andrews, Elizabeth M. Aquino Peterson, Christopher K.E. Bleck, Laurel G. Mendelsohn, Valerie M. Mitchell, Billy S. Collins, Neelam R. Redekar, Skyler A. Kuhn, Christian A. Combs, Mehdi Pirooznia, Pradeep K. Dagur, David S.J. Allan, Daniella M. Schwartz, Richard W. Childs, Tiffany M. Powell-Wiley
Yvonne Baumer, Komudi Singh, Abhinav Saurabh, Andrew S. Baez, Cristhian A. Gutierrez-Huerta, Long Chen, Muna Igboko, Briana S. Turner, Josette A. Yeboah, Robert N. Reger, Lola R. Ortiz-Whittingham, Sahil Joshi, Marcus R. Andrews, Elizabeth M. Aquino Peterson, Christopher K.E. Bleck, Laurel G. Mendelsohn, Valerie M. Mitchell, Billy S. Collins, Neelam R. Redekar, Skyler A. Kuhn, Christian A. Combs, Mehdi Pirooznia, Pradeep K. Dagur, David S.J. Allan, Daniella M. Schwartz, Richard W. Childs, Tiffany M. Powell-Wiley
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Research Article Cardiology Immunology

Obesity modulates NK cell activity via LDL and DUSP1 signaling for populations with adverse social determinants

Abstract

African American (AA) women are disproportionately affected by obesity and hyperlipidemia, particularly in the setting of adverse social determinants of health (aSDoH) that contribute to health disparities. Obesity, hyperlipidemia, and aSDoH appear to impair NK cells. As potential common underlying mechanisms are largely unknown, we sought to investigate common signaling pathways involved in NK cell dysfunction related to obesity and hyperlipidemia in AA women from underresourced neighborhoods. We determined in freshly isolated NK cells that obesity and measures of aSDoH were associated with a shift in NK cell subsets away from CD56dim/CD16+ cytotoxic NK cells. Using ex vivo data, we identified LDL as a marker related to NK cell function in an AA population from underresourced neighborhoods. Additionally, NK cells from AA women with obesity and LDL-treated NK cells displayed a loss in NK cell function. Comparative unbiased RNA-sequencing analysis revealed DUSP1 as a common factor. Subsequently, chemical inhibition of Dusp1 and Dusp1 overexpression in NK cells highlighted its significance in NK cell function and lysosome biogenesis in a mTOR/TFEB-related fashion. Our data demonstrate a pathway by which obesity and hyperlipidemia in the setting of aSDoH may relate to NK cell dysfunction, making DUSP1 an important target for further investigation of health disparities.

Authors

Yvonne Baumer, Komudi Singh, Abhinav Saurabh, Andrew S. Baez, Cristhian A. Gutierrez-Huerta, Long Chen, Muna Igboko, Briana S. Turner, Josette A. Yeboah, Robert N. Reger, Lola R. Ortiz-Whittingham, Sahil Joshi, Marcus R. Andrews, Elizabeth M. Aquino Peterson, Christopher K.E. Bleck, Laurel G. Mendelsohn, Valerie M. Mitchell, Billy S. Collins, Neelam R. Redekar, Skyler A. Kuhn, Christian A. Combs, Mehdi Pirooznia, Pradeep K. Dagur, David S.J. Allan, Daniella M. Schwartz, Richard W. Childs, Tiffany M. Powell-Wiley

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Figure 4

Comparative analysis of 2 RNA-sequencing sets reveals DUSP1 as an overlapping significantly upregulated gene and important regulator of NK cell function.

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Comparative analysis of 2 RNA-sequencing sets reveals DUSP1 as an overla...
(A–C) Freshly isolated primary NK cells from age-matched AA women with (W/O) or without (WO/O) obesity (dataset 1, n = 5 each group) or healthy donors treated with vehicle or LDL overnight (dataset 2, n = 4) were subjected to RNA-sequencing analysis. (A and B) Heatmap of differentially expressed genes, significant at an adjusted P ≤ 0.1 and fold change (FC) ≥ 1.5 in (A) W/O vs. WO/O and (B) LDL vs. control comparisons. (C) Venn diagram showing the overlap of differentially expressed genes from 2 comparisons identified a single gene (DUSP1) being commonly upregulated. (D) Flow cytometry analysis of Dusp1 protein expression in NK cells with indicated treatments (n = 6, unpaired 2-tailed t test). (E–I) Freshly isolated primary NK cells were treated with LDL with or without Dusp1 inhibitor. (E) Scanning electron microscopy (SEM) imaging of treated NK cells (n = 3). Arrows point to protrusions of NK cells. Original magnification, ×8,500 (left); ×7,000 (right) (scale bar: 5 μm). (F) Labeling F-actin (FITC-Phalloidin) allowed for the quantification of cells presenting protrusions (n = 6 independent experiments with at least 5 visual fields analyzed per condition; Kruskal-Wallis test with Dunn’s correction) (scale bar: 5 μm). (G) Flow cytometry–based detection of degranulation (CD107a) and intracellular cytokine presence after exposure to K562 cells (n = 9, CD107a/IFN-γ; n = 8, TNF-α; repeated-measures 1-way ANOVA with Tukey’s correction). (H) Cytokine release was analyzed from supernatants. (I) RT-qPCR analysis was performed to determine changes in IFNG or TNFA mRNA expression (n = 7, repeated-measures 1-way ANOVA with Šidák correction). (J and K) Dusp1 was overexpressed in NK92 cells. Experiments are carried out comparing empty vector (EV) control with Dusp1-overexpressing NK92 cells. Flow cytometry–based analysis of extracellular CD107a and intracellular cytokine presence was performed after exposure to K562 cells. Cytokine secretion was measured using ELISA (K) (n = 6 each, unpaired t test for all, except Mann-Whitney for TNF-α dataset; all tests were 2 tailed). Significance was established at P < 0.05; asterisks indicate significance between groups. *P < 0.05; **P < 0.01; ***P < 0.001.