Sex-specific sequels of early life stress on serine/threonine kinase activity in visceral adipose tissue from obese mice

Abstract

Adverse childhood experiences (ACEs) are an established independent risk factor for chronic disease including obesity and hypertension; however, only women exposed to multiple ACEs show a positive relationship with BMI. Our lab has reported that maternal separation and early weaning (MSEW), a mouse model of early life stress, induces sex-specific mechanisms underlying greater blood pressure response to a chronic high fat diet (HF). Specifically, female MSEW mice fed a HF display exacerbated perigonadal white adipose tissue (pgWAT) expansion and a metabolic syndrome-like phenotype compared to control counterparts, whereas hypertension is caused by sympathoactivation in male MSEW mice. Thus, this study aimed to determine whether there is a sex-specific serine/threonine kinase (STKA) activity in pgWAT adipose tissue associated with early life stress. Frozen pgWAT was collected from MSEW and control, male and female mice fed a HF to assess STKA activity using the Pamstation12 instrument. Overall, MSEW induces significant reduction of 7 phosphokinases (|Z| >=1.5) in females (QIK, MLK, PKCH, MST, STE7, PEK, FRAY) and 5 in males (AKT, SGK, P38, MARK, CDK), while 15 were downregulated in both sexes (DMPK, PKA, PKG, RSK, PLK, DYRK, NMO, CAMK1, JNK, PAKA, RAD53, ERK, PAKB, PKD, PIM, AMPK). This data provides new insights into the sex-specific dysregulation of the molecular network controlling cellular phosphorylation signals in visceral adipose tissue and identifies possible target phosphokinases implicated in adipocyte hypertrophy as a result of exposure to early life stress. Identifying functional metabolic signatures is critical to elucidate the underlying molecular mechanisms behind the sex-specific obesity risk associated with early life stress.

Keywords: ACE; BMI; Kinome; sex differences.

Figure 1:

PamGene STK array analysis. Sample allocation is visualized across three PamGene STK chips (A). Signal intensities are of differentially phosphorylated peptides for each sample are visualized in a heatmap (B). Signal intensities averaged from technical replicates visualized in a heatmap (C).

Figure 2:

Analysis and prediction of differentially active kinases in males. Heat map of peptide phosphorylation signal intensities from MSEW and C male adipose tissue samples (A). MSEW and C signal intensities for 49 peptide hits displayed using linear-fit model (B). Waterfall plot of peptide hits showing variation across 3 technical replicates (C). Reverse KRSA plot of predicted differentially-active kinases in MSEW male adipose tissue (D).

Figure 3:

Analysis and prediction of differentially active kinases in females. Heat map of peptide phosphorylation signal intensities from MSEW and C female adipose tissue samples (A). MSEW and C signal intensities for 51 peptide hits displayed using linear-fit model (B). Waterfall plot of peptide hits showing variation across 3 technical replicates (C). Reverse KRSA plot of predicted differentially-active kinases in MSEW female adipose tissue (D).

Figure 4:

Differentially-activated kinases in male and female MSEW and C adipose tissue samples. Venn diagram of kinases predicted by KRSA analysis to be differentially-activated in male and female mouse adipose tissue at a Z-score significance of 2 (A), 1.75 (B), and 1.5 (C).