👤 Jean Paul Thiery

A low ankle-brachial Index (ABI) is an established condition for peripheral artery disease (PAD) and cardiovascular disease risk. The search for genetic determinants of the ankle-brachial index (ABI) is important to better understand molecular patho-cmechanisms of PAD and its commonalities with cardiovascular diseases (CVD), supporting development of new drug targets and tailored preventive or therapeutic measures. To search for genetic factors contributing to ankle-brachial index, we integrated genome-wide association meta-analysis and transcriptome-wide association meta-analysis (TWAMA) of two German cohorts, the population-based LIFE-Adult cohort and LIFE-Heart, a cohort of patients with suspected or confirmed coronary artery disease. Pathway analysis of identified genes was used to explore biological mechanisms potentially involved in ABI pathophysiology. Finally, we analysed co-associations of known CAD or carotid plaque associations with ABI to detect possible genetic commonalities. By our GWAS meta-analysis, we identified four new gene loci associated with ABI that are also linked with coronary artery diseases (CAD) (6q26: LPA and 11q14.1: DLG2) or cholesterol levels (12q21.31: TMTC2 and Xp21.1: DMD). Furthermore, we replicated a known ABI locus on cytoband 9p21.3 (CDKN2B) and four loci associated with PAD. In our TWAMA, we identified 145 blood transcripts associated with ABI at FDR 5% level. Gene set enrichment analysis of all TWAMA results revealed the inflammation-related pathways interferon gamma response, neutrophil degranulation, and interferon alpha response as the top three upregulated pathways in patients with lower ABI. Among overlapping genes between blood TWAMA and tissue-specific genetically regulated gene-expression association analysis, 24 genes showed consistent effect directions at nominal significance, with lower ABI-associated genes relating to stress response and vascular integrity, while higher ABI-associated genes linked to cellular homeostasis and metabolism. In our integrated genome- and transcriptome-wide meta-analysis, we identified novel and confirmed known candidate genes and pathways associated with ABI. Association signals partly overlap with those of other cardiovascular traits such as CAD and carotid plaque formation. The integration of gene-expression data, validated known and added new molecular insight how inflammatory signalling can contribute to atherosclerosis and vascular dysfunction. These findings pave the way for improved understanding of the molecular underpinnings of PAD and inform future strategies for targeted prevention and therapy. Show less

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a key player of lipid metabolism with higher plasma levels in women throughout their life. Statin treatment affects PCSK9 levels also showing evidence of sex-differential effects. It remains unclear whether these differences can be explained by genetics. We performed genome-wide association meta-analyses (GWAS) of PCSK9 levels stratified for sex and statin treatment in six independent studies of Europeans (8936 women/11,080 men respectively 14,825 statin-free/5191 statin-treated individuals). Loci associated in one of the strata were tested for statin- and sex-interactions considering all independent signals per locus. Independent variants at the PCSK9 gene locus were then used in a stratified Mendelian Randomization analysis (cis-MR) of PCSK9 effects on low-density lipoprotein cholesterol (LDL-C) levels to detect differences of causal effects between the subgroups. We identified 11 loci associated with PCSK9 in at least one stratified subgroup (p < 1.0 × 10 We performed the first double-stratified GWAS of PCSK9 levels and identified multiple biologically plausible loci with genetic interaction effects. Our results indicate that the observed sexual dimorphism of PCSK9 and its statin-related interactions have a genetic basis. Significant differences in the causal relationship between PCSK9 and LDL-C suggest sex-specific dosages of PCSK9 inhibitors. Show less

Triple-negative subtype of breast cancer (TNBC) is hallmarked by frequent disease relapse and shows highest mortality rate. Although PD-1/PD-L1 immune checkpoint blockades have recently shown promising clinical benefits, the overall response rate remains largely insufficient. Hence, alternative therapeutic approaches are warranted. Given the immunosuppressive properties of CD73-mediated adenosine release, CD73 blocking approaches are emerging as attractive strategies in cancer immunotherapy. Understanding the precise mechanism regulating the expression of CD73 is required to develop effective anti-CD73-based therapy. Our previous observations demonstrate that the transcription factors driving epithelial-to-mesenchymal transition (EMT-TF) can regulate the expression of several inhibitory immune checkpoints. Here we analyzed the role of the EMT-TF SNAI1 in the regulation of CD73 in TNBC cells. We found that doxycycline-driven SNAI1 expression in the epithelial -like TNBC cell line MDA-MB-468 results in CD73 upregulation by direct binding to the CD73 proximal promoter. SNAI1-dependent upregulation of CD73 leads to increased production and release of extracellular adenosine by TNBC cells and contributes to the enhancement of TNBC immunosuppressive properties. Our data are validated in TNBC samples by showing a positive correlation between the mRNA expression of CD73 and SNAI1. Overall, our results reveal a new CD73 regulation mechanism in TNBC that participates in TNBC-mediated immunosuppression and paves the way for developing new treatment opportunities for CD73-positive TNBC. Show less

In East Asia, the breast cancer incidence rate among women aged <50 years has rapidly increased. Emerging tumors are distinctly characterized by a high prevalence of estrogen receptor (ER)-positive/human epidermal growth factor receptor (HER2)-negative cancer. In the present study, we identified unique genetic alterations in these emerging tumors. We analyzed gene copy number variations (CNVs) in breast tumors from 120 Taiwanese patients, and obtained public datasets of CNV and gene expression (GE). The data regarding CNV and GE were separately compared between East Asian and Western patients, and the overlapping genes identified in the comparisons were explored to identify the gene-gene interaction networks. In the age <50 years/ER + /HER2- subgroup, tumors of East Asian patients exhibited a higher frequency of copy number loss in APOA1/C3/A4/A5, a lipid-metabolizing gene cluster (33 vs. 10%, P < .001) and lower APOA1/C3/A4/A5 expressions than tumors of Western patients. These copy number loss related- and GE-related results were validated in another Taiwanese cohort and in two GE datasets, respectively. The copy number loss was significantly associated with poor survival among Western patients, but not among East Asian patients. Lower APOA1, APOC3, and APOA5 expressions were associated with higher ESTIMATE immune scores, indicating an abundance of tumor-infiltrating immune cells. In conclusion, APOA1/C3/A4/A5 copy number loss was more prevalent in luminal breast tumors among East Asian women aged <50 years, and its immunomodulatory effect on the tumor microenvironment possibly plays various roles in the tumor biology of East Asian patients. Show less

CMTM6 is a critical regulator of cell surface expression of PD-L1 in tumor cells, but little is known about the transcriptional regulation of CMTM6. Here we report that the expression of CMTM6 positively correlates with the epithelial to mesenchymal transition (EMT) score in breast cancer cell lines and with the major EMT marker Vimentin in triple-negative breast cancers (TNBC). We showed that CMTM6 is concomitantly overexpressed with PD-L1 in breast mesenchymal compared with the epithelial cells. Driving a mesenchymal phenotype in SNAI1-inducible MCF-7 cells (MCF-7 Show less

Dyslipidemia is a major risk factor for atherosclerotic cardiovascular disease (ASCVD). As key regulators of lipoprotein metabolism, apolipoproteins (apos) are discussed as vascular risk factors. This study aimed to analyze associations of major plasma apos with coronary artery disease (CAD), peripheral artery disease (PAD) and carotid artery plaque (CAP) to elucidate their diagnostic potential in risk assessment. ApoA-I, apoA-II, apoA-IV, apoB-100, apoC-I, apoC-III, apoE, and apoJ were simultaneously quantified in 3 μL EDTA-plasma by LC-MS/MS in a case-control subgroup of the Leipziger LIFE-Heart Study (N = 911). Confounder analysis with demographic, clinical covariates and serum lipids, cardiac, inflammatory, and hepatic markers were performed. Apos were associated with CAD, CAP, and PAD in a multivariate regression model. Fasting and statin therapy showed strongest effects on apo concentrations. Inverse correlations of HDL-related apos A-I, A-II, A-IV, and C-I were observed for troponin T and interleukin 6. Concentrations of apos A-II, B-100, C-I, and E were decreased under statin therapy. After adjustment for influencing factors and related lipids, only apoB-100 (odds ratio per one SD [OR], 1.39; 95% confidence interval [CI], 1.05-1.84) was independently associated with CAD while apoA-IV (OR, 0.74; 95% CI 0.58-0.95) indicated PAD. ApoB-100 (OR, 1.55; 95% CI, 1.18-2.04), apoC-III (OR, 1.30; 95% CI, 1.06-1.58), and apoE (OR, 1.34; 95% CI, 1.13-1.58) were associated with CAP. Triglyceride rich lipoproteins (TRLs) associated apos A-IV, B-100, C-III, and E are independently associated with stable ASCVD, providing further evidence for a potential role of TRLs in atherogenesis. Show less

Steroid hormones are important regulators of physiological processes in humans and are under genetic control. A link to coronary artery disease (CAD) is supposed. Our main objective was to identify genetic loci influencing steroid hormone levels. As a secondary aim, we searched for causal effects of steroid hormones on CAD. We conducted genome-wide meta-association studies for eight steroid hormones: cortisol, dehydroepiandrosterone sulfate (DHEAS), estradiol, and testosterone in two independent cohorts (LIFE-Adult, LIFE-Heart, maximum n = 7667), and progesterone, 17-hydroxyprogesterone, androstenedione, and aldosterone in LIFE-Heart only (maximum n = 2070). All genome-wide significant loci were tested for sex interactions. Furthermore, we tested whether previously reported CAD single-nucleotide polymorphisms were associated with our steroid hormone panel and investigated causal links between hormone levels and CAD status using Mendelian randomization (MR) approaches. We discovered 15 novel associated loci for 17-hydroxyprogesterone, progesterone, DHEAS, cortisol, androstenedione, and estradiol. Five of these loci relate to genes directly involved in steroid metabolism, that is, CYP21A1, CYP11B1, CYP17A1, STS, and HSD17B12, almost completing the set of steroidogenic enzymes with genetic associations. Sexual dimorphisms were found for seven of the novel loci. Other loci correspond, for example, to the WNT4/β-catenin pathway. MR revealed that cortisol, androstenedione, 17-hydroxyprogesterone, and DHEA-S had causal effects on CAD. We also observed enrichment of cortisol and testosterone associations among known CAD hits. Our study greatly improves insight into genetic regulation of steroid hormones and their dependency on sex. These results could serve as a basis for analyzing sexual dimorphism in other complex diseases. Show less

Differentiation of adipocytes is a highly regulated process modulated by multiple transcriptional co-activators and co-repressors. JMJD1C belongs to the family of jumonji C (jmjC) domain-containing histone demethylases and was originally described as a ligand-dependent co-activator of thyroid hormone and androgen receptors. Here, we explored the potential role of Jmjd1c in white adipocyte differentiation. To investigate the relevance of Jmjd1c in adipogenesis, murine 3T3-L1 preadipocyte cells with transient knock-down of Jmjd1c (3T3_Jmjd1c) were generated. Depletion of Jmjd1c led to the formation of smaller lipid droplets, reduced accumulation of triglycerides and maintenance of a more fibroblast-like morphology after adipocyte differentiation. Concomitantly, insulin stimulated uptake of glucose and fatty acids was significantly reduced in 3T3_Jmjd1c adipocytes. In line with these observations we detected lower expression of key genes associated with lipid droplet formation (Plin1, Plin4, Cidea) and uptake of glucose and fatty acids (Glut4, Fatp1, Fatp4, Aqp7) respectively. Finally, we demonstrate that depletion of Jmjd1c interferes with mitotic clonal expansion (MCE), increases levels of H3K9me2 (dimethylation of lysine 9 of histone H3) at promotor regions of adipogenic transcription factors (C/EBPs and PPARγ) and leads to reduced induction of these key regulators. In conclusion, we have identified Jmjd1c as a modulator of adipogenesis. Our data suggest that Jmjd1c may participate in MCE and the activation of the adipogenic transcription program during the induction phase of adipocyte differentiation in 3T3-L1 cells. Show less

Autophagy, a "self-eating" cellular process, has dual roles in promoting and suppressing tumor growth, depending on cellular context. PTP4A3/PRL-3, a plasma membrane and endosomal phosphatase, promotes multiple oncogenic processes including cell proliferation, invasion, and cancer metastasis. In this study, we demonstrate that PTP4A3 accumulates in autophagosomes upon inhibition of autophagic degradation. Expression of PTP4A3 enhances PIK3C3-BECN1-dependent autophagosome formation and accelerates LC3-I to LC3-II conversion in an ATG5-dependent manner. PTP4A3 overexpression also enhances the degradation of SQSTM1, a key autophagy substrate. These functions of PTP4A3 are dependent on its catalytic activity and prenylation-dependent membrane association. These results suggest that PTP4A3 functions to promote canonical autophagy flux. Unexpectedly, following autophagy activation, PTP4A3 serves as a novel autophagic substrate, thereby establishing a negative feedback-loop that may be required to fine-tune autophagy activity. Functionally, PTP4A3 utilizes the autophagy pathway to promote cell growth, concomitant with the activation of AKT. Clinically, from the largest ovarian cancer data set (GSE 9899, n = 285) available in GEO, high levels of expression of both PTP4A3 and autophagy genes significantly predict poor prognosis of ovarian cancer patients. These studies reveal a critical role of autophagy in PTP4A3-driven cancer progression, suggesting that autophagy could be a potential Achilles heel to block PTP4A3-mediated tumor progression in stratified patients with high expression of both PTP4A3 and autophagy genes. Show less

Multiple lines of evidence suggest that fatty acids (FA) play an important role in cognitive function. However, little is known about the functional genetic pathways involved in cognition. The main goals of this study were to replicate previously reported interaction effects between breast feeding (BF) and FA desaturase (FADS) genetic variation on IQ and to investigate the possible mechanisms by which these variants might moderate BF effect, focusing on brain expression. Using a sample of 534 twins, we observed a trend in the moderation of BF effects on IQ by FADS2 variation. In addition, we made use of publicly available gene expression databases from both humans (193) and mice (93) and showed that FADS2 variants also correlate with FADS1 brain expression (P-value<1.1E-03). Our results provide novel clues for the understanding of the genetic mechanisms regulating FA brain expression and improve the current knowledge of the FADS moderation effect on cognition. Show less

Dyslipidemia is a frequent component of the metabolic disorder of diabetic patients contributing to organ damage. Herein, in low-density lipoprotein receptor-deficient hyperlipidemic and streptozotozin-induced diabetic mice, hyperglycemia and hyperlipidemia acted reciprocally, accentuating renal injury and altering renal function. In hyperglycemic-hyperlipidemic kidneys, the accumulation of Tip47-positive lipid droplets in glomeruli, tubular epithelia, and macrophages was accompanied by the concomitant presence of the oxidative stress markers xanthine oxidoreductase and nitrotyrosine, findings that could also be evidenced in renal biopsy samples of diabetic patients. As liver X receptors (LXRα,β) regulate genes linked to lipid and carbohydrate homeostasis and inhibit inflammatory gene expression in macrophages, the effects of systemic and macrophage-specific LXR activation were analyzed on renal damage in hyperlipidemic-hyperglycemic mice. LXR stimulation by GW3965 up-regulated genes involved in cholesterol efflux and down-regulated proinflammatory/profibrotic cytokines, inhibiting the pathomorphology of diabetic nephropathy, renal lipid accumulation, and improving renal function. Xanthine oxidoreductase and nitrotyrosine levels were reduced. In macrophages, GW3965 or LXRα overexpression significantly suppressed glycated or acetylated low-density lipoprotein-induced cytokines and reactive oxygen species. Specifically, in mice, transgenic expression of LXRα in macrophages significantly ameliorated hyperlipidemic-hyperglycemic nephropathy. The results demonstrate the presence of lipid droplet-induced oxidative mechanisms and the pathophysiologic role of macrophages in diabetic kidneys and indicate the potent regulatory role of LXRs in preventing renal damage in diabetes. Show less

Elevated cholesterol levels in children can be a risk factor for cardiovascular diseases in later life. In adults, it has been shown that blood lipid levels are strongly influenced by polymorphisms in the fatty acid desaturase (FADS) gene cluster in addition to nutritional and other exogenous and endogenous determinants. Our aim was to investigate whether lipid levels are determined by the FADS genotype already in children and whether this association interacts with dietary intake of n-3 fatty acids. The analysis was based on data of 2006 children from two German prospective birth cohort studies. Total cholesterol, HDL, LDL and triglycerides were measured at 10 years of age. Six single nucleotide polymorphisms (SNPs) of the FADS gene cluster were genotyped. Dietary n-3 fatty acid intake was assessed by food frequency questionnaire. Linear regression modeling was used to assess the association between lipid levels, n-3 fatty acid intake and FADS genotype. Individuals carrying the homozygous minor allele had lower levels of total cholesterol [means ratio (MR) ranging from 0.96 (p = 0.0093) to 0.98 (p = 0.2949), depending on SNPs] and LDL [MR between 0.94 (p = 0.0179) and 0.97 (p = 0.2963)] compared to homozygous major allele carriers. Carriers of the heterozygous allele showed lower HDL levels [β between -0.04 (p = 0.0074) to -0.01 (p = 0.3318)] and higher triglyceride levels [MR ranging from 1.06 (p = 0.0065) to 1.07 (p = 0.0028)] compared to homozygous major allele carriers. A higher n-3 PUFA intake was associated with higher concentrations of total cholesterol, LDL, HDL and lower triglyceride levels, but these associations did not interact with the FADS1 FADS2 genotype. Total cholesterol, HDL, LDL and triglyceride concentrations may be influenced by the FADS1 FADS2 genotype already in 10 year old children. Genetically determined blood lipid levels during childhood might differentially predispose individuals to the development of cardiovascular diseases later in life. Show less

Liver X receptors (LXR)-α,β regulate intracellular cholesterol homeostasis and inhibit inflammatory gene expression. We studied the effects of the LXRα,β-agonist GW3965 on acute and chronic organ damage in the F344-LEW rat kidney transplantation model. In addition, to gain LXR isoform and cell-specific insights BALB/c kidneys were transplanted into mice with macrophage overexpression of LXRα (mLXRα-tg) and evaluated 7 and 42 days after transplantation. After 56 days GW3965 improved significantly function and morphology of rat kidney allografts by substantial reduction of mononuclear cell infiltrate and fibrosis; in vitro GW3965 reduced inflammatory activity of bone marrow-derived macrophages (BMDMs) and alloreactivity of T cells. Kidneys transplanted into mLXRα-tg mice were also protected from development of chronic allograft dysfunction. Similarly to GW3965-activated BMDMs, mLXRα-tg macrophages secreted significantly less monocyte chemoattractant protein 1 and macrophage inflammatory protein 1β. Interestingly, 7 days after transplantation, when the total number of intragraft macrophages did not differ, evidently more arginase 1- and mannose receptor C type 1-positive cells were found in LXR rat and mice kidney allografts; in vitro both LXR activation by GW3965 and mLXRα overexpression accentuated the induction of alternative activation of BMDMs by IL-4/IL-13, suggesting an additional mechanism by LXRs to prevent graft damage. The results highlight the relevance of macrophage LXRα in allograft rejection and prevention of fibrosis. Show less

C-reactive protein (CRP) is a heritable marker of chronic inflammation that is strongly associated with cardiovascular disease. We sought to identify genetic variants that are associated with CRP levels. We performed a genome-wide association analysis of CRP in 66 185 participants from 15 population-based studies. We sought replication for the genome-wide significant and suggestive loci in a replication panel comprising 16 540 individuals from 10 independent studies. We found 18 genome-wide significant loci, and we provided evidence of replication for 8 of them. Our results confirm 7 previously known loci and introduce 11 novel loci that are implicated in pathways related to the metabolic syndrome (APOC1, HNF1A, LEPR, GCKR, HNF4A, and PTPN2) or the immune system (CRP, IL6R, NLRP3, IL1F10, and IRF1) or that reside in regions previously not known to play a role in chronic inflammation (PPP1R3B, SALL1, PABPC4, ASCL1, RORA, and BCL7B). We found a significant interaction of body mass index with LEPR (P<2.9×10(-6)). A weighted genetic risk score that was developed to summarize the effect of risk alleles was strongly associated with CRP levels and explained ≈5% of the trait variance; however, there was no evidence for these genetic variants explaining the association of CRP with coronary heart disease. We identified 18 loci that were associated with CRP levels. Our study highlights immune response and metabolic regulatory pathways involved in the regulation of chronic inflammation. Show less

Background- The nuclear liver X receptor-alpha (LXR-alpha) has been implicated in the regulation of intracellular cholesterol homeostasis, inflammatory response, and atherosclerosis susceptibility. The aim of the present study was to test whether transgenic expression of LXR-alpha might affect these mechanisms and result in a reduction of atherosclerosis. We generated mice with macrophage overexpression of mouse LXR-alpha, evidenced by significantly elevated expression levels of LXR-target genes (ABCA1, ABCG1) in these cells. For atherosclerosis studies, mice were crossed onto the LDL-receptor deficient background. Plasma lipids and lipoproteins as well as liver triglycerides were not significantly different between transgenic animals and nontransgenic controls. However, lesion area at the brachiocephalic artery (BCA) was significantly reduced (-83%, P=0.02) in male LXR-alpha transgenic mice. This was associated with a significantly increased cholesterol efflux to acceptor-free media (+24%, P=0.002) and ApoA1 containing media (+20%, P<0.0001) as well as reduced lipopolysaccharide (LPS)-induced NO-release from macrophages of transgenic animals, providing a potential mechanism for the reduction of atherosclerosis. Our data show for the first time that transgenic overexpression of LXR-alpha in macrophages has significant antiatherogenic properties. We conclude that overexpression of LXR-alpha in macrophages might be useful as a therapeutic principle for the prevention of atherosclerosis. Show less