Circulating microRNAs and endothelial cell migration rate are associated with metabolic syndrome and fitness level in postmenopausal African American women

Abstract

Postmenopausal African American women are at elevated risk for metabolic syndrome (MetS), which predisposes them to cardiovascular disease and other chronic diseases. Circulating microRNAs (ci-miR) are potential mediators of cardiometabolic diseases also impacted by cardiorespiratory fitness (CRF) level. Using real-time quantitative PCR, we compared the expression of vascular-related ci-miRs (miR-21-5p, miR-92a-3p, miR-126-5p, miR-146a-5p, miR-150-5p, miR-221-3p) in sedentary, overweight/obese, postmenopausal African American women based on 1) presence (n = 31) or absence (n = 42) of MetS and 2) CRF level (VO_2peak ) (Very Low < 18.0 mL·kg^-1 ·min^-1 [n = 31], Low = 18.0-22.0 mL·kg^-1 ·min^-1 [n = 24], or Moderate >22.0 mL·kg^-1 ·min^-1 [n = 18]). Endothelial migration rate in response to subjects' serum was assessed to determine the effect of circulating blood-borne factors on endothelial repair. Ci-miR-21-5p was the only ci-miR that differed between women with MetS compared to those without MetS (0.93 ± 0.43 vs. 1.28 ± 0.71, P = 0.03). There were borderline significant differences (P = 0.06-0.09) in ci-miR-21-5p, 126-5p, and 221-3p levels between the CRF groups, and these three ci-miRs correlated with VO_2peak (r = -0.25 to -0.28, P < 0.05). Endothelial migration rate was impaired in response to serum from women with MetS compared to those without after 16-24 h. Serum from women with Moderate CRF induced greater endothelial migration than the Very Low and Low CRF groups after 4 and 16-24 h, that was also not different from a young, healthy reference group. Ci-miR-21-5p is lower in postmenopausal African American women with MetS, while ci-miRs-21-5p, 126-5p, and 221-3p are associated with CRF. Factors which impair endothelial cell migration rate are present in serum of women with MetS, though having Moderate CRF may be protective.

Keywords: Cardiorespiratory fitness; circulating microRNA; endothelium; menopause; metabolic syndrome.

Figure 1

Relative expression (2^‐ΔΔCT method) of ci‐miR levels in serum of postmenopausal African American women with (MetS; n = 26) and without (Non‐MetS; n = 36) Metabolic Syndrome. Bars represent means ± SD. *P < 0.05 versus Non‐MetS.

Figure 2

Receiver operating characteristic (ROC) curve analysis of the accuracy of ci‐miR‐21‐5p expression alone or in combination with VO_2peak (mL·kg⁻¹·min⁻¹) to differentiate women (n = 62) based on presence of MetS. Ci‐miR‐21‐5p: area under the curve (AUC) = 0.628, 95% CI = 0.488–0.769; P = 0.09. Ci‐miR‐21‐5p + VO_2peak (AUC = 0.665, 95% CI = 0.531–0.799; P = 0.03.

Figure 3

Relative expression (2^‐ΔΔCT method) of ci‐miR in serum of postmenopausal African American women grouped by cardiorespiratory fitness (CRF) level (Very Low [VO_2peak < 18.0 mL·kg⁻¹ min⁻¹; n = 26], Low [=18.0–22.0 mL·kg⁻¹·min⁻¹; n = 21], and Moderate [>22.0 mL·kg⁻¹·min⁻¹; n = 15]). Bars represent means ± SD.

Figure 4

Correlations of ci‐miR‐21‐5p, ci‐miR‐126‐5p, and ci‐miR‐221‐3p with relative VO_2peak (mL·kg⁻¹·min⁻¹) n = 62.

Figure 5

Endothelial migration in response to serum of postmenopausal women (A) grouped based on presence (MetS; n = 25)/absence (Non‐MetS; n = 37) of Metabolic Syndrome compared to healthy, young women (n = 7). *P < 0.05 versus MetS, †P < 0.05 versus Non‐MetS. (B) Endothelial migration in response to serum of women grouped by cardiorespiratory fitness (CRF) level (Very Low [VO_2peak < 18.0 mL·kg⁻¹ min⁻¹; n = 25], Low [=18.0–22.0 mL·kg⁻¹·min⁻¹; n = 21], and Moderate [>22.0 mL·kg⁻¹·min⁻¹; n = 16]) compared to young, healthy women (n = 7). *P < 0.05 versus Very Low, †P < 0.05 versus Low. There were borderline significant (b.s.) differences at 8 h for young, healthy versus Very Low (P = 0.071) and Low (P = 0.078), as well as Moderate versus Very Low (P = 0.065) and Low (P = 0.085). Means ± SD. (C) Representative images of endothelial migration in response to serum of postmenopausal women with Low and Moderate cardiorespiratory fitness (CRF). Endothelial cells were exposed to 5% serum in endothelial growth medium, migration was tracked over 24 h and calculated as (100 – (size of wound area at time point/size of initial wound area ×100)). The 0 h images were taken immediately upon addition of serum, while the 24 h image in response to serum of a woman with Moderate CRF shows 100% migration. Images were taken under a light microscope at 5× magnification.