Genome-wide gene expression profiles in antioxidant pathways and their potential sex differences and connections to vitamin C in mice

Vitamin C Is Essential for the Maintenance of Skeletal Muscle Functions

Vitamin C (L-ascorbic acid, VC) is a water-soluble antioxidant essential for collagen polymerization. Previously, we reported that long-term VC deficiency causes muscle atrophy and deterioration in physical ability using female senescence marker protein-30 (SMP30)-deficient mice with a lack of VC synthesis, which is similar to that observed in humans. To determine whether these findings also hold true for male SMP30-deficient mice, two-month-old male SMP30-deficient mice were divided into two groups: the VC-treated group (VC(+)) was administered 1.5 g/L VC, and the VC-untreated group (VC(−)) was supplied water without VC. The VC level at four weeks in the gastrocnemius muscles from the VC(+) and VC(−) groups was 205.7 ± 8.5 nmol/g tissue and 13.1 ± 0.6 nmol/g tissue, respectively. Thus, four weeks was enough to reduce the VC level in the skeletal muscle in the VC-untreated group. On the other hand, muscle weights of the gastrocnemius, soleus, plantaris, tibialis anterior, and extensor digitorum longus in the VC(−) group were significantly reduced by VC deficiency after twelve weeks. The physical endurance of the VC(−) group at eight weeks was markedly lower than that of the VC(+) group. The grasping strength and activity in the cage in the nocturnal phases of the VC(−) group were markedly lower at twelve and sixteen weeks than those of the VC(+) group. Interestingly, muscle atrophy and declined physical ability were completely restored with VC supplementation for twelve weeks after VC deficiency. Thus, VC is essential for maintaining skeletal muscle function in both male and female SMP30-deficient mice with a lack of VC synthesis.

Association of Leukemia Target Genes Tet2, Bcl2, and Slc23a2 in Vitamin C Pathways

BACKGROUND

Vitamin C has been used in combination with several target genes in the treatment of leukemia. Tet methylcytosine dioxygenase (Tet2), B-cell lymphoma 2 (Bcl2), and solute carrier family 23 member 2 (Slc23a2) are the major target genes in the treatment of leukemia and are relevant to vitamin C.

MATERIALS AND METHODS

Using whole-genome expression profiles from mouse livers, the expression quantitative trait locus (eQTL), correlation matrix, and gene network graph were constructed with probes from each of these three genes and with their relative genes. The function of key genes was examined by their pathways and reported information. The results indicated that although direct correlations among their expression levels were not strong, alternative connecting pathways were discovered. By comparing the expression levels of one probe with known sequences from each of the three genes, we identified several key genes, induced myeloid leukemia cell differentiation protein (Mcl1), far upstream element-binding protein 1 (Fubp1), and tumor protein D52-like 2 (Tpd52l2), which play important roles in acute lymphocytic leukemia and acute myelocytic leukemia. In conclusion, Alternative pathways and key genes that connect Tet2, Bcl2, and Slc23a2 for their therapeutic applications with vitamin C were identified.

Sex Differences in Correlation with Gene Expression Levels between Ifi200 Family Genes and Four Sets of Immune Disease-Relevant Genes

Background

The HIN-200 family genes in humans have been linked to several autoimmune diseases—particularly to systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). Recently, its human counterpart gene cluster, the Ifi200 family in mice, has been linked to spontaneous arthritis disease (SAD). However, many immune-mediated diseases (including RA and SLE) show gender difference. Understanding whether or not and how these genes play a role in sex difference in immune-mediated diseases is essential for diagnosis/treatment.

Methods

This study takes advantage of the whole genome gene expression profiles of recombinant inbred (RI) strain populations from female and male mice to analyze potential sex differences in a variety of genes in disease pathways. Expression levels and regulatory QTL of Ifi200 family genes between female and male mice were first examined in a large mouse population, including RI strains derived from C57BL/6J, DBA/2J (BXD), and classic inbred strains. Sex similarities and differences were then analyzed for correlations with gene expression levels between genes in the Ifi200 family and four selected gene sets: known immune Ifi200 pathway-related genes, lupus-relevant genes, osteoarthritis- (OA-) and RA-relevant genes, and sex hormone-related genes.

Results

The expression level of Ifi202b showed the most sex difference in correlation with known immune-related genes (the P value for Ifi202b is 0.0004). Ifi202b also showed gender difference in correlation with selected sex hormone genes, with a P value of 0.0243. When comparing coexpression levels between Ifi200 genes and lupus-relevant genes, Ifi203 and Ifi205 showed significant sex difference (P values: 0.0303 and 0.002, resp.). Furthermore, several key genes (e.g., Csf1r, Ifnb1, IL-20, IL-22, IL-24, Jhdm1d, Csf1r, Ifnb1, IL-20, IL-22, IL-24, and Tgfb2 that regulate sex differences in immune diseases) were discovered.

Conclusions

Different genes in the Ifi200 family play different roles in sex difference among dissimilar pathways of these four gene groups.

Effects of dietary antioxidant vitamins on lung functions according to gender and smoking status in Korea: a population-based cross-sectional study

OBJECTIVE

Cigarette smoke-induced oxidative stress plays an important role in the pathogenesis of chronic obstructive pulmonary disease (COPD). Dietary antioxidants are thought to prevent smoke-induced oxidative damage. The aim of this study was to investigate associations between lung function and the consumption of antioxidant vitamins in Korean adults.

METHODS

In total, 21 148 participants from the Korean National Health and Nutrition Examination Survey (2007-2014) were divided into four groups based on smoking history and gender. Multivariate regression models were used to evaluate associations between lung function and intake of dietary antioxidants.

RESULTS

Subjects in the highest intake quintile (Q5) of vitamin A, carotene and vitamin C intake had mean forced expiratory volume in 1 s (FEV₁) measurements that were 30 mL, 32 mL and 36 mL higher than those of individuals in the lowest intake quintile (Q1), respectively (p for trend; p=0.008, p=0.010 and p<0.001, respectively). The risks of COPD for male smokers in Q1 increased 7.60-fold (95% CI 5.92 to 9.76), 7.16-fold (95% CI 5.58 to 9.19) and 7.79-fold (95% CI 6.12 to 9.92), for vitamin A, carotene and vitamin C, respectively, compared with those of female non-smokers in Q5. Among patients with COPD, men who smoked >20 pack-years had mean FEV₁ measurements that were 192 mL, 149 mL and 177 mL higher than those of patients in Q1 (p for trend; p=0.018, p=0.024 and p=0.043, for vitamin A, carotene and vitamin C, respectively).

CONCLUSIONS

These findings indicate that the influence of antioxidant vitamins on lung function depends on gender and smoking status in the Korean COPD population.

Sex difference in EGFR pathways in mouse kidney-potential impact on the immune system

Background

Epidermal growth factor receptor (Egfr) has been the target of several drugs for cancers. The potential gender differences in genes in the Egfr axis have been suggested in humans and in animal models. Female and male mice from the same recombinant inbred (RI) strain have the same genomic components except the sex difference. A population of different RI mouse strains allows to conduct precise analysis of molecular pathways and regulation of Egfr between female and male mice.

Methods

The whole genome expression profiles of 70 genetically diverse RI strains of mice were used to compare three major molecular aspects of Egfr gene: the relative expression levels, gene network and expression quantitative trait loci (eQTL) that regulate the expression of Egfr between female and male mice.

Results

Our data showed that there is a significant sex difference in the expression levels in kidney. A considerable number of genes in the gene network of Egfr are sex differentially expressed. The expression levels of Egfr in mice are statistical significant different between C57BL/6 J (B6) and DBA/2 J (D2) genotypes in male while no difference in female mice. The eQTLs that regulate the expression levels of Egfr between female and male mice are also different. Furthermore, the differential expression levels of Egfr showed significantly different correlations with two known biological traits between male and female mice.

Conclusion

Overall there is a substantial sex difference in the Egfr pathways in mice. These data may have significant impact on drug target design, development, formulation, and dosage determinant for women and men in clinical trials.

Electronic supplementary material

The online version of this article (doi:10.1186/s12863-016-0449-3) contains supplementary material, which is available to authorized users.

Decreased expression levels of Ifi genes is associated to the increased resistance to spontaneous arthritis disease in mice deficiency of IL-1RA

Background

The mouse strain BALB/c deficient in IL-1 receptor antagonist protein (Il-1ra) develops spontaneous arthritis disease (SAD) while the strain DBA/1 IL1rn^-/- with the same deficiency does not. Previously, we mapped a QTL on chromosome 1 for SAD and then developed a congenic mouse strain BALB.D1-1^-/- that contains the QTL genomic fragment associated with resistance from DBA/1^-/- on a BALB/c^-/- background. The congenic strain was relatively resistant to spontaneous arthritis and had delayed onset and reduced severity of disease. We obtained whole genome expression profiles from the spleen of the congenic strain BALB.D1-1^-/- and four other strains, the wild type BALB/c, DBA/1 and the deficient DBA/1 IL1rn^-/- and the BALB/c IL1rn^-/-. We then compared the similarities and differences between the congenic strain and the four parental strains. Here we report the selected potential causal genes based on differential expression levels as well as function of genes.

Results

There is a considerable number of genes that are differentially expressed between the congenic strain and the three parental strains, BALB/c, DBA/1, and DBA/1^-/-. However there only a few differentially expressed genes were identified by comparing the congenic strain and the BALB/c^-/-strain. These differentially expressed genes are mainly from T-cell receptor beta chain (Tcrb) and interferon-activatable protein (Ifi) genes. These genes are also differentially expressed between congenic strain and BALB/c strains. However, their expression levels in the congenic strain are similar to that in DBA/1 and DBA/1^-/-. The expression level of Tcrb-j gene is positively associated with two genes of Ifi gene 200 cluster.

Conclusions

Decreased expression levels of Ifi genes is associated to the increased resistance to spontaneous arthritis disease and with down regulation of expressions of Tcrb genes in the mouse congenic strain. Ifi genes may play an important role in the susceptibility to SAD in mice.

Electronic supplementary material

The online version of this article (doi:10.1186/s12865-016-0163-y) contains supplementary material, which is available to authorized users.

Total, Dietary, and Supplemental Vitamin C Intake and Risk of Incident Kidney Stones

BACKGROUND

Previous studies of vitamin C and kidney stones were conducted mostly in men and either reported disparate results for supplemental and dietary vitamin C or did not examine dietary vitamin C.

STUDY DESIGN

Prospective cohort analysis.

SETTING & PARTICIPANTS

156,735 women in the Nurses' Health Study (NHS) I and II and 40,536 men in the Health Professionals Follow-up Study (HPFS).

PREDICTOR

Total, dietary, and supplemental vitamin C intake, adjusted for age, body mass index, thiazide use, and dietary factors.

OUTCOMES

Incident kidney stones.

RESULTS

During a median follow-up of 11.3 to 11.7 years, 6,245 incident kidney stones were identified. After multivariable adjustment, total vitamin C intake (<90 [reference], 90-249, 250-499, 500-999, and ≥1,000mg/d) was not significantly associated with risk for kidney stones among women, but was among men (HRs of 1.00 [reference], 1.19 [95% CI, 0.99-1.46], 1.15 [95% CI, 0.93-1.42], 1.29 [95% CI, 1.04-1.60], and 1.43 [95% CI, 1.15-1.79], respectively; P for trend = 0.005). Median total vitamin C intake for the 500- to 999-mg/d category was ∼700mg/d. Supplemental vitamin C intake (no use [reference], <500, 500-999, and ≥1,000mg/d) was not significantly associated with risk for kidney stones among women, but was among men (HR, 1.19 [95% CI, 1.01-1.40] for ≥1,000mg/d; P for trend = 0.001). Dietary vitamin C intake was not associated with stones among men or women, although few participants had dietary intakes > 700mg/d.

LIMITATIONS

Nutrient intakes derived from food-frequency questionnaires, lack of data on stone composition for all cases.

CONCLUSIONS

Total and supplemental vitamin C intake was significantly associated with higher risk for incident kidney stones in men, but not in women.

Sex Difference of Egfr Expression and Molecular Pathway in the Liver: Impact on Drug Design and Cancer Treatments?

Epidermal growth factor receptor (EGFR) has been used as the target in drug design for cancer treatment including the liver cancer. Men and women have different levels of EGFR expression during the life. The whole genome expression profiles of livers of recombinant inbred (RI) strains derived from C57BL/6J (B6) X DBA/2J (D2) were used to compare three major molecular aspects of Egfr gene: the relative expression levels, gene network and eQTLs that regulate the expression of Egfr between female and male mice. Our data suggest that there is a significant difference in the expression levels in the liver between female and male mice. Several important genes in the gene network of Egfr are differentially expressed between female and male mice. The regulatory elements for the expression levels of Egfr between female and male mice are also different. In summary, our data reveals an important sex difference in the Egfr pathways in the liver of the mice. These data may have substantial impact on drug development and dosage determinant for women and men in the clinical trials.

Genome wide analysis of sex difference in gene expression profiles of bone formations using sfx mice and BXD RI strains

The objective of this study is to identify sex differentially expressed genes in bone using a mouse model of spontaneous fracture, sfx, which lacks the gene for L-gulonolactone oxidase (Gulo), a key enzyme in the ascorbic acid (AA) synthesis pathway. We first identified the genes that are differentially expressed in the femur between female and male in sfx mice. We then analyzed the potential gene network among those differentially expressed genes with whole genome expression profiles generated using spleens of female and male mice of a total of 67 BXD (C57BL/6J X DBA/2J) recombinant inbred (RI) and other strains. Our result indicated that there was a sex difference in the whole genome profiles in sfx mice as measured by the proportion of up- and downregulated genes. Several genes in the pathway of bone development are differentially expressed between the male and female of sfx mice. Comparison of gene network of up- and downregulated bone relevant genes also suggests a sex difference.