Negative perception of socioeconomic status with depressive mood down-regulates expression of PPBP and SLC1A7 genes in peripheral blood leukocytes

Figures & data

Table 1. Characteristics of self-reported questionnaires and salivary cortisol in 129 subjects

Characteristics		n	Mean ± SD
Age	All	129	44.0 ± 13.0
	Male	27	46.3 ± 11.7
	Female	102	43.4 ± 13.3
Body mass index	All	125	21.7 ± ± 2.9
	Male	27	23.1 ± 2.5
	Female	98	21.3 ± 2.9
STAI-state	All	129	45.2 ± 9.5
	Male	27	41.3 ± 10.0
	Female	102	46.3 ± 9.1
STAI-trait	All	129	48.1 ± 11.6
	Male	27	44.0 ± 13.9
	Female	102	49.2 ± 10.8
SDS	All	129	42.8 ± 7.5
	Male	27	39.0 ± 7.3
	Female	102	43.8 ± ± 7.3
Salivary cortisol	All	88	1.6 ± 2.19
	Male	20	1.51 ± 1.13
	Female	68	1.58 ± 2.42

Notes: Salivary cortisol levels are provided in μg/dl.

n = number; STAI = Spielberger’s state-trait anxiety inventory; SDS = Zung self-rating depression scale.

Table 2. Scores of SSS

	Total (n = 72)	Males (n = 16)	Females (n = 56)	p-value
SSS	5.44 ± 1.80	6.31 ± 0.91	5.20 ± 1.02	0.02*

Notes: Each value shows mean ± SD. n = number; SSS = subjective socioeconomic status.

* p < 0.05 by student’s t-test.

Figure 1. Distribution of SSS scores. Participants (16 males and 56 females) reported their socioeconomic state using the self-anchoring striving scale in the form of a 10-rung ladder as described in Methods section.

Table 3. Multiple regression analysis for the associations between SSS and characteristics

Characteristics	SSS
	Standard partial regression coefficients (β)	t	p-value
BMI	−0.034	−0.284	0.778
STAI-state	−0.152	−1.285	0.203
STAI-trait	−0.187	−1.540	0.128
SDS	−0.275	−2.221	0.030*
Salivary cortisol	0.064	0.713	0.478

* p < 0.05 by Multiple regression analysis.

Figure 2. Ingenuity pathway analysis (IPA) of differentially expressed genes between the low- and high-SSS groups. (A) The top 5-scored canonical pathways significantly modified by the 522 differentially expressed genes between the high- and low-SSS groups were analyzed by IPA. The threshold (p < 0.05) is shown by a dotted line. (B) The top 5-scored biological functions significantly modified by these genes were analyzed by IPA. The threshold (p < 0.05) is shown by a dotted line. (C) The network of genes which relate to EIF2 signaling is displayed graphically as nodes (gene) and edges (the biological relationship between genes). The color intensity indicates the genes up-regulated (red) or down-regulated (green) in the low-SSS group compared with the high-SSS group.

Table 4. Deferentially expressed genes in EIF2 signaling in the low-SSS compared with the high-SSS group

Gene symbol	Gene name	Fold change
Up-regulated
EIF1AX	Eukaryotic translation initiation factor 1A, X-linked	1.46
RPL7	Ribosomal protein L7	1.43
RPL9	Ribosomal protein L9	1.58
RPL17	Ribosomal protein L17	1.49
RPL21	Ribosomal protein L21	1.45
RPL23	Ribosomal protein L23	1.44
RPL26	Ribosomal protein L26	1.47
RPL27	Ribosomal protein L27	1.29
RPL31	Ribosomal protein L31	1.61
RPL34	Ribosomal protein L34	1.65
RPL35	Ribosomal protein L35	1.26
RPL39	Ribosomal protein L39	1.39
RPL41	Ribosomal protein L41	1.39
RPL13A	Ribosomal protein L13a	1.31
RPL22L1	Ribosomal protein L22 like 1	1.40
RPL26L1	Ribosomal protein L26 like 1	1.65
RPS7	Ribosomal protein S7	1.56
RPS17	Ribosomal protein S17	1.41
RPS21	Ribosomal protein S21	1.30
RPS24	Ribosomal protein S24	1.52
RPS27	Ribosomal protein S27	1.43
RPS27L	Ribosomal protein S27 like	1.46
RPS3A	Ribosomal protein S3A	1.70
Down-regulated
PDPK1	3-phosphoinositide dependent protein kinase 1	−1.29
RAF1	Raf-1 proto-oncogene, serine/threonine kinase	−1.27
PIK3CD	Phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit delta	−1.34

Figure 3. Expression of PPBP and SLC1A7 mRNAs in peripheral blood leukocytes from subjects. (A) The mRNA levels for PPBP and SLC1A7 were measured by qPCR and compared between the low- and high-SSS groups. Values are means ± SD. (B) The correlation between SSS scores and PPBP or SLC1A7 mRNA levels in 72 subjects was analyzed by a multiple regression analysis.

Table 5. Multiple regression analysis for the association between SSS and gene expression levels

Gene	SSS
	Standard partial regression coefficients (β)	t	p-value
PPBP	−0.453	−4.46	3.26E-05**
SLC1A7	−0.252	−2.30	0.02*
CARD9	0.162	1.39	0.17
HNRNPU	−0.030	−0.25	0.80

* p < 0.05 by Multiple regression analysis.

** p < 0.01 by Multiple regression analysis.