👤 Detlev Erdmann

Aged skin is prone to viral infections, but the mechanisms responsible for this immunosenescent immune risk are unclear. We observed that aged murine and human skin expressed reduced levels of antiviral proteins (AVPs) and circadian regulators, including Bmal1 and Clock. Bmal1 and Clock were found to control rhythmic AVP expression in skin, and such circadian control of AVPs was diminished by disruption of immune cell IL-27 signaling and deletion of Bmal1/Clock genes in mouse skin, as well as siRNA-mediated knockdown of CLOCK in human primary keratinocytes. We found that treatment with the circadian-enhancing agents nobiletin and SR8278 reduced infection of herpes simplex virus 1 in epidermal explants and human keratinocytes in a BMAL1/CLOCK-dependent manner. Circadian-enhancing treatment also reversed susceptibility of aging murine skin and human primary keratinocytes to viral infection. These findings reveal an evolutionarily conserved and age-sensitive circadian regulation of cutaneous antiviral immunity, underscoring circadian restoration as an antiviral strategy in aging populations. Show less

Aged skin is prone to viral infections, but the mechanisms responsible for this immunosenescent immune risk are unclear. We observed that aged murine and human skin expressed reduced antiviral proteins (AVPs) and circadian regulators including Bmal1 and Clock. Bmal1 and Clock were found to control rhythmic AVP expression in skin and such circadian-control of AVPs was diminished by disruption of immune cell interleukin 27 signaling and deletion of Bmal1/Clock genes in mouse skins, as well as siRNA-mediated knockdown of CLOCK in human primary keratinocytes. We found that treatment of circadian enhancing agents, nobiletin and SR8278, reduced infection of herpes simplex virus 1 (HSV1) in epidermal explants and human keratinocytes in a Bmal1/Clock-dependent manner. Circadian enhancing treatment also reversed susceptibility of aging murine skin and human primary keratinocytes to viral infection. These findings reveal an evolutionarily conserved and age-sensitive circadian regulation of cutaneous antiviral immunity, underscoring circadian restoration as an antiviral strategy in aging populations. Show less

UVR and immunosuppression are major risk factors for cutaneous squamous cell carcinoma (cSCC). Regulatory T cells promote cSCC carcinogenesis, and in other solid tumors, infiltrating regulatory T cells and CD8 Show less

The ninefold radial arrangement of microtubule triplets (MTTs) is the hallmark of the centriole, a conserved organelle crucial for the formation of centrosomes and cilia. Although strong cohesion between MTTs is critical to resist forces applied by ciliary beating and the mitotic spindle, how the centriole maintains its structural integrity is not known. Using cryo-electron tomography and subtomogram averaging of centrioles from four evolutionarily distant species, we found that MTTs are bound together by a helical inner scaffold covering ~70% of the centriole length that maintains MTTs cohesion under compressive forces. Ultrastructure Expansion Microscopy (U-ExM) indicated that POC5, POC1B, FAM161A, and Centrin-2 localize to the scaffold structure along the inner wall of the centriole MTTs. Moreover, we established that these four proteins interact with each other to form a complex that binds microtubules. Together, our results provide a structural and molecular basis for centriole cohesion and geometry. Show less

In colorectal cancer (CRC), aberrant Wnt signalling is essential for tumorigenesis and maintenance of cancer stem cells. However, how other oncogenic pathways converge on Wnt signalling to modulate stem cell homeostasis in CRC currently remains poorly understood. Using large-scale compound screens in CRC, we identify MEK1/2 inhibitors as potent activators of Wnt/β-catenin signalling. Targeting MEK increases Wnt activity in different CRC cell lines and murine intestine in vivo. Truncating mutations of APC generated by CRISPR/Cas9 strongly synergize with MEK inhibitors in enhancing Wnt responses in isogenic CRC models. Mechanistically, we demonstrate that MEK inhibition induces a rapid downregulation of AXIN1. Using patient-derived CRC organoids, we show that MEK inhibition leads to increased Wnt activity, elevated LGR5 levels and enrichment of gene signatures associated with stemness and cancer relapse. Our study demonstrates that clinically used MEK inhibitors inadvertently induce stem cell plasticity, revealing an unknown side effect of RAS pathway inhibition. Show less

Genome-wide association studies have identified multiple loci associated with coronary artery disease and myocardial infarction, but only a few of these loci are current targets for on-market medications. To identify drugs suitable for repurposing and their targets, we created 2 unique pipelines integrating public data on 49 coronary artery disease/myocardial infarction-genome-wide association studies loci, drug-gene interactions, side effects, and chemical interactions. We first used publicly available genome-wide association studies results on all phenotypes to predict relevant side effects, identified drug-gene interactions, and prioritized candidates for repurposing among existing drugs. Second, we prioritized gene product targets by calculating a druggability score to estimate how accessible pockets of coronary artery disease/myocardial infarction-associated gene products are, then used again the genome-wide association studies results to predict side effects, excluded loci with widespread cross-tissue expression to avoid housekeeping and genes involved in vital processes and accordingly ranked the remaining gene products. These pipelines ultimately led to 3 suggestions for drug repurposing: pentolinium, adenosine triphosphate, and riociguat (to target CHRNB4, ACSS2, and GUCY1A3, respectively); and 3 proteins for drug development: LMOD1 (leiomodin 1), HIP1 (huntingtin-interacting protein 1), and PPP2R3A (protein phosphatase 2, regulatory subunit b-double prime, α). Most current therapies for coronary artery disease/myocardial infarction treatment were also rediscovered. Integration of genomic and pharmacological data may prove beneficial for drug repurposing and development, as evidence from our pipelines suggests. Show less

Genome-wide association studies have so far identified 56 loci associated with risk of coronary artery disease (CAD). Many CAD loci show pleiotropy; that is, they are also associated with other diseases or traits. This study sought to systematically test if genetic variants identified for non-CAD diseases/traits also associate with CAD and to undertake a comprehensive analysis of the extent of pleiotropy of all CAD loci. In discovery analyses involving 42,335 CAD cases and 78,240 control subjects we tested the association of 29,383 common (minor allele frequency >5%) single nucleotide polymorphisms available on the exome array, which included a substantial proportion of known or suspected single nucleotide polymorphisms associated with common diseases or traits as of 2011. Suggestive association signals were replicated in an additional 30,533 cases and 42,530 control subjects. To evaluate pleiotropy, we tested CAD loci for association with cardiovascular risk factors (lipid traits, blood pressure phenotypes, body mass index, diabetes, and smoking behavior), as well as with other diseases/traits through interrogation of currently available genome-wide association study catalogs. We identified 6 new loci associated with CAD at genome-wide significance: on 2q37 (KCNJ13-GIGYF2), 6p21 (C2), 11p15 (MRVI1-CTR9), 12q13 (LRP1), 12q24 (SCARB1), and 16q13 (CETP). Risk allele frequencies ranged from 0.15 to 0.86, and odds ratio per copy of the risk allele ranged from 1.04 to 1.09. Of 62 new and known CAD loci, 24 (38.7%) showed statistical association with a traditional cardiovascular risk factor, with some showing multiple associations, and 29 (47%) showed associations at p < 1 × 10 We identified 6 loci associated with CAD at genome-wide significance. Several CAD loci show substantial pleiotropy, which may help us understand the mechanisms by which these loci affect CAD risk. Show less

Coronary artery disease (CAD) is a leading cause of morbidity and mortality worldwide. Although 58 genomic regions have been associated with CAD thus far, most of the heritability is unexplained, indicating that additional susceptibility loci await identification. An efficient discovery strategy may be larger-scale evaluation of promising associations suggested by genome-wide association studies (GWAS). Hence, we genotyped 56,309 participants using a targeted gene array derived from earlier GWAS results and performed meta-analysis of results with 194,427 participants previously genotyped, totaling 88,192 CAD cases and 162,544 controls. We identified 25 new SNP-CAD associations (P < 5 × 10 Show less

Constitutive activation of the antiapoptotic nuclear factor-κB (NF-κB) signaling pathway is a hallmark of the activated B-cell-like (ABC) subtype of diffuse large B-cell lymphomas (DLBCL). Recurrent oncogenic mutations are found in the scaffold protein CARMA1 (CARD11) that connects B-cell receptor (BCR) signaling to the canonical NF-κB pathway. We asked how far additional downstream processes are activated and contribute to the oncogenic potential of DLBCL-derived CARMA1 mutants. To this end, we expressed oncogenic CARMA1 in the NF-κB negative DLBCL lymphoma cell line BJAB. By a proteomic approach we identified recruitment of β-catenin and its destruction complex consisting of APC, AXIN1, CK1α and GSK3β to oncogenic CARMA1. Recruitment of the β-catenin destruction complex was independent of CARMA1-BCL10-MALT1 complex formation or constitutive NF-κB activation and promoted the stabilization of β-catenin. The β-catenin destruction complex was also recruited to CARMA1 in ABC DLBCL cell lines, which coincided with elevated β-catenin expression. In line, β-catenin was frequently detected in non-GCB DLBCL biopsies that rely on chronic BCR signaling. Increased β-catenin amounts alone were not sufficient to induce classical WNT target gene signatures, but could augment TCF/LEF-dependent transcriptional activation in response to WNT signaling. In conjunction with NF-κB, β-catenin enhanced expression of immunosuppressive interleukin-10 and suppressed antitumoral CCL3, indicating that β-catenin can induce a favorable tumor microenvironment. Thus, parallel activation of NF-κB and β-catenin signaling by gain-of-function mutations in CARMA1 augments WNT stimulation and is required for regulating the expression of distinct NF-κB target genes to trigger cell-intrinsic and extrinsic processes that promote DLBCL lymphomagenesis. Show less

Metabolites derived from dietary choline and L-carnitine, such as trimethylamine N-oxide and betaine, have recently been identified as novel risk factors for atherosclerosis in mice and humans. We sought to identify genetic factors associated with plasma betaine levels and determine their effect on risk of coronary artery disease (CAD). A two-stage genome-wide association study (GWAS) identified two significantly associated loci on chromosomes 2q34 and 5q14.1. The lead variant on 2q24 (rs715) localizes to carbamoyl-phosphate synthase 1 (CPS1), which encodes a mitochondrial enzyme that catalyses the first committed reaction and rate-limiting step in the urea cycle. Rs715 is also significantly associated with decreased levels of urea cycle metabolites and increased plasma glycine levels. Notably, rs715 yield a strikingly significant and protective association with decreased risk of CAD in only women. These results suggest that glycine metabolism and/or the urea cycle represent potentially novel sex-specific mechanisms for the development of atherosclerosis. Show less

Myocardial infarction (MI), a leading cause of death around the world, displays a complex pattern of inheritance. When MI occurs early in life, genetic inheritance is a major component to risk. Previously, rare mutations in low-density lipoprotein (LDL) genes have been shown to contribute to MI risk in individual families, whereas common variants at more than 45 loci have been associated with MI risk in the population. Here we evaluate how rare mutations contribute to early-onset MI risk in the population. We sequenced the protein-coding regions of 9,793 genomes from patients with MI at an early age (≤50 years in males and ≤60 years in females) along with MI-free controls. We identified two genes in which rare coding-sequence mutations were more frequent in MI cases versus controls at exome-wide significance. At low-density lipoprotein receptor (LDLR), carriers of rare non-synonymous mutations were at 4.2-fold increased risk for MI; carriers of null alleles at LDLR were at even higher risk (13-fold difference). Approximately 2% of early MI cases harbour a rare, damaging mutation in LDLR; this estimate is similar to one made more than 40 years ago using an analysis of total cholesterol. Among controls, about 1 in 217 carried an LDLR coding-sequence mutation and had plasma LDL cholesterol > 190 mg dl(-1). At apolipoprotein A-V (APOA5), carriers of rare non-synonymous mutations were at 2.2-fold increased risk for MI. When compared with non-carriers, LDLR mutation carriers had higher plasma LDL cholesterol, whereas APOA5 mutation carriers had higher plasma triglycerides. Recent evidence has connected MI risk with coding-sequence mutations at two genes functionally related to APOA5, namely lipoprotein lipase and apolipoprotein C-III (refs 18, 19). Combined, these observations suggest that, as well as LDL cholesterol, disordered metabolism of triglyceride-rich lipoproteins contributes to MI risk. Show less

Plasma triglyceride levels are heritable and are correlated with the risk of coronary heart disease. Sequencing of the protein-coding regions of the human genome (the exome) has the potential to identify rare mutations that have a large effect on phenotype. We sequenced the protein-coding regions of 18,666 genes in each of 3734 participants of European or African ancestry in the Exome Sequencing Project. We conducted tests to determine whether rare mutations in coding sequence, individually or in aggregate within a gene, were associated with plasma triglyceride levels. For mutations associated with triglyceride levels, we subsequently evaluated their association with the risk of coronary heart disease in 110,970 persons. An aggregate of rare mutations in the gene encoding apolipoprotein C3 (APOC3) was associated with lower plasma triglyceride levels. Among the four mutations that drove this result, three were loss-of-function mutations: a nonsense mutation (R19X) and two splice-site mutations (IVS2+1G→A and IVS3+1G→T). The fourth was a missense mutation (A43T). Approximately 1 in 150 persons in the study was a heterozygous carrier of at least one of these four mutations. Triglyceride levels in the carriers were 39% lower than levels in noncarriers (P<1×10(-20)), and circulating levels of APOC3 in carriers were 46% lower than levels in noncarriers (P=8×10(-10)). The risk of coronary heart disease among 498 carriers of any rare APOC3 mutation was 40% lower than the risk among 110,472 noncarriers (odds ratio, 0.60; 95% confidence interval, 0.47 to 0.75; P=4×10(-6)). Rare mutations that disrupt APOC3 function were associated with lower levels of plasma triglycerides and APOC3. Carriers of these mutations were found to have a reduced risk of coronary heart disease. (Funded by the National Heart, Lung, and Blood Institute and others.). Show less

The strong observational association between total homocysteine (tHcy) concentrations and risk of coronary artery disease (CAD) and the null associations in the homocysteine-lowering trials have prompted the need to identify genetic variants associated with homocysteine concentrations and risk of CAD. We tested whether common genetic polymorphisms associated with variation in tHcy are also associated with CAD. We conducted a meta-analysis of genome-wide association studies (GWAS) on tHcy concentrations in 44,147 individuals of European descent. Polymorphisms associated with tHcy (P < 10(⁻⁸) were tested for association with CAD in 31,400 cases and 92,927 controls. Common variants at 13 loci, explaining 5.9% of the variation in tHcy, were associated with tHcy concentrations, including 6 novel loci in or near MMACHC (2.1 × 10⁻⁹), SLC17A3 (1.0 × 10⁻⁸), GTPB10 (1.7 × 10⁻⁸), CUBN (7.5 × 10⁻¹⁰), HNF1A (1.2 × 10⁻¹²)), and FUT2 (6.6 × 10⁻⁹), and variants previously reported at or near the MTHFR, MTR, CPS1, MUT, NOX4, DPEP1, and CBS genes. Individuals within the highest 10% of the genotype risk score (GRS) had 3-μmol/L higher mean tHcy concentrations than did those within the lowest 10% of the GRS (P = 1 × 10⁻³⁶). The GRS was not associated with risk of CAD (OR: 1.01; 95% CI: 0.98, 1.04; P = 0.49). We identified several novel loci that influence plasma tHcy concentrations. Overall, common genetic variants that influence plasma tHcy concentrations are not associated with risk of CAD in white populations, which further refutes the causal relevance of moderately elevated tHcy concentrations and tHcy-related pathways for CAD. Show less

Hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM) can both be due to mutations in the genes encoding β-myosin heavy chain (MYH7) or cardiac myosin-binding protein C (MYBPC3). The aim of the present study was to determine the prevalence and spectrum of mutations in both genes in German HCM and DCM patients and to establish novel genotype-to-phenotype correlations. Coding exons and intron flanks of the two genes MYH7 and MYBPC3 of 236 patients with HCM and 652 patients with DCM were sequenced by conventional and array-based means. Clinical records were established following standard protocols. Mutations were detected in 41 and 11% of the patients with HCM and DCM, respectively. Differences were observed in the frequency of splice site and frame-shift mutations in the gene MYBPC3, which occurred more frequently (P< 0.02, P< 0.001, respectively) in HCM than in DCM, suggesting that cardiac myosin-binding protein C haploinsufficiency predisposes to hypertrophy rather than to dilation. Additional novel genotype-to-phenotype correlations were found in HCM, among these a link between MYBPC3 mutations and a particularly large thickness of the interventricular septum (P= 0.04 vs. carriers of a mutation in MYH7). Interestingly, this correlation and a link between MYH7 mutations and a higher degree of mitral valve regurgitation held true for both HCM and DCM, indicating that the gene affected by a mutation may determine the magnitude of structural and functional alterations in both HCM and DCM. A large clinical-genetic study has unravelled novel genotype-to-phenotype correlations in HCM and DCM which warrant future investigation of both the underlying mechanisms and the prognostic use. Show less

Obesity is globally prevalent and highly heritable, but its underlying genetic factors remain largely elusive. To identify genetic loci for obesity susceptibility, we examined associations between body mass index and ∼ 2.8 million SNPs in up to 123,865 individuals with targeted follow up of 42 SNPs in up to 125,931 additional individuals. We confirmed 14 known obesity susceptibility loci and identified 18 new loci associated with body mass index (P < 5 × 10⁻⁸), one of which includes a copy number variant near GPRC5B. Some loci (at MC4R, POMC, SH2B1 and BDNF) map near key hypothalamic regulators of energy balance, and one of these loci is near GIPR, an incretin receptor. Furthermore, genes in other newly associated loci may provide new insights into human body weight regulation. Show less

Sphingolipids have essential roles as structural components of cell membranes and in cell signalling, and disruption of their metabolism causes several diseases, with diverse neurological, psychiatric, and metabolic consequences. Increasingly, variants within a few of the genes that encode enzymes involved in sphingolipid metabolism are being associated with complex disease phenotypes. Direct experimental evidence supports a role of specific sphingolipid species in several common complex chronic disease processes including atherosclerotic plaque formation, myocardial infarction (MI), cardiomyopathy, pancreatic beta-cell failure, insulin resistance, and type 2 diabetes mellitus. Therefore, sphingolipids represent novel and important intermediate phenotypes for genetic analysis, yet little is known about the major genetic variants that influence their circulating levels in the general population. We performed a genome-wide association study (GWAS) between 318,237 single-nucleotide polymorphisms (SNPs) and levels of circulating sphingomyelin (SM), dihydrosphingomyelin (Dih-SM), ceramide (Cer), and glucosylceramide (GluCer) single lipid species (33 traits); and 43 matched metabolite ratios measured in 4,400 subjects from five diverse European populations. Associated variants (32) in five genomic regions were identified with genome-wide significant corrected p-values ranging down to 9.08x10(-66). The strongest associations were observed in or near 7 genes functionally involved in ceramide biosynthesis and trafficking: SPTLC3, LASS4, SGPP1, ATP10D, and FADS1-3. Variants in 3 loci (ATP10D, FADS3, and SPTLC3) associate with MI in a series of three German MI studies. An additional 70 variants across 23 candidate genes involved in sphingolipid-metabolizing pathways also demonstrate association (p = 10(-4) or less). Circulating concentrations of several key components in sphingolipid metabolism are thus under strong genetic control, and variants in these loci can be tested for a role in the development of common cardiovascular, metabolic, neurological, and psychiatric diseases. Show less

Defects in nine sarcomeric protein genes are known to cause hypertrophic cardiomyopathy (HCM). Mutation types and frequencies in large cohorts of consecutive and unrelated patients have not yet been determined. We, therefore, screened HCM patients for mutations in six sarcomeric genes: myosin-binding protein C3 (MYBPC3), MYH7, cardiac troponin T (TNNT2), alpha-tropomyosin (TPM1), cardiac troponin I (TNNI3), and cardiac troponin C (TNNC1). HCM was diagnosed in 108 consecutive patients by echocardiography (septum >15 mm, septal/posterior wall >1.3 mm), angiography, or based on a state after myectomy. Single-strand conformation polymorphism analysis was used for mutation screening, followed by DNA-sequencing. A total of 34 different mutations were identified in 108 patients: 18 mutations in MYBPC3 in 20 patients [intervening sequence (intron) 7 + 1G > A and Q1233X were found twice], 13 missense mutations in MYH7 in 14 patients (R807H was found twice), and one amino acid change in TPM1, TNNT2, and TNNI3, respectively. No disease-causing mutation was found in TNNC1. Cosegregation with the HCM phenotype could be demonstrated for 13 mutations (eight mutations in MYBPC3 and five mutations in MYH7). Twenty-eight of the 37 mutation carriers (76%) reported a positive family history with at least one affected first-grade relative; only eight mutations occurred sporadically (22%). MYBPC3 was the gene that most frequently caused HCM in our population. Systematic mutation screening in large samples of HCM patients leads to a genetic diagnosis in about 30% of unrelated index patients and in about 57% of patients with a positive family history. Show less

Mutations in sarcomeric protein genes have been reported to cause dilated cardiomyopathy (DCM). In order to detect novel mutations we screened the sarcomeric protein genes beta-myosin heavy chain (MYH7), myosin-binding protein C (MYBPC3), troponin T (TNNT2), and alpha-tropomyosin (TPM1) in 46 young patients with DCM. Mutation screening was done using single-strand conformation polymorphism (SSCP) analysis and DNA sequencing. The mutations in MYH7 were projected onto the protein data bank-structure (pdb) of myosin of striated muscle. In MYH7 two mutations (Ala223Thr and Ser642Leu) were found in two patients. Ser642Leu is part of the actin-myosin interface. Ala223Thr affects a buried residue near the ATP binding site. In MYBPC3 we found one missense mutation (Asn948Thr) in a male patient. None of the mutations were found in 88 healthy controls and in 136 patients with hypertrophic cardiomyopathy (HCM). Thus mutations in HCM causing genes are not rare in DCM and have potential for functional relevance. Show less

We studied the clinical and genetic features of hypertrophic cardiomyopathy (HCM) caused by mutations in the myosin-binding protein C gene (MYBPC3) in 110 consecutive, unrelated patients and family members of European descent. Mutations in the MYBPC3 gene represent the cause of HCM in approximately 15% of familial cases. MYBPC3 mutations were reported to include mainly nonsense versus missense mutations and to be characterized by a delayed onset and benign clinical course of the disease in Japanese and French families. We investigated the features that characterize MYBPC3 variants in a large, unrelated cohort of consecutive patients. The MYBPC3 gene was screened by single-strand conformational polymorphism analysis and sequencing. The clinical phenotypes were analyzed using rest and 24-h electrocardiography, electrophysiology, two-dimensional and Doppler echocardiography and angiography. We identified 13 mutations in the MYBPC3 gene: one nonsense, four missense and three splicing mutations and five small deletions and insertions. Of these, 11 were novel, and two were probably founder mutations. Patients with MYBPC3 mutations presented a broad range of phenotypes. In general, the 16 carriers of protein truncations had a tendency toward earlier disease manifestations (33 +/- 13 vs. 48 +/- 9 years; p = 0.06) and more frequently needed invasive procedures (septal ablation or cardioverter-defibrillator implantation) compared with the 9 carriers of missense mutations or in-frame deletions (12/16 vs. 1/9 patients; p < 0.01). Multiple mutations, which include missense, nonsense and splicing mutations, as well as small deletions and insertions, occur in the MYBPC3 gene. Protein truncation mutations seem to cause a more severe disease phenotype than missense mutations or in-frame deletions. Show less