Genome-wide association scan identifies variants near Matrix Metalloproteinase (MMP) genes on chromosome 11q21-22 strongly associated with serum MMP-1 levels

Inhibition of matrix metalloproteinases to reduce blood brain barrier disruption and haemorrhagic transformation in ischaemic stroke: Go broad or go narrow?

Ischaemic stroke characterises impulsive cerebral-region hypoxia due to deep intracerebral arteriole blockage, often accompanied by permanent cerebral infarction and cognitive impairment. Thrombolysis with recombinant tissue plasminogen activator (rtPA) and thrombectomy remain the only guidance-approved therapies. However, emerging data draws clear links between such therapies and haemorrhage transformation, which occur when cerebral vasculature is damaged during ischaemia/reperfusion. Studies have shown that matrix metalloproteinases (MMPs) play a significant role in haemorrhage transformation, by depleting the extracellular matrix (ECM) and disrupting the blood brain barrier (BBB). Inhibitors of MMPs may be used to prevent ischaemic stroke patients from BBB disruption and haemorrhage transformation, particularly for those receiving rtPA treatment. Preclinical studies found that inhibition of MMPs with agents or in knock out mice, effectively reduced BBB disruption and infarct volume, leading to improved ischaemic stroke outcomes. At present, MMP inhibition is not an approved therapy for stroke patients. There remain concerns about timing, dosing, duration of MMP inhibition and selection of either broad spectrum or specific MMP inhibitors for stroke patients. This review aims to summarize current knowledge on MMP inhibition in ischaemic stroke and explore whether a broad spectrum or a specific MMP inhibitor should be used for ischaemic stroke patient treatment. It is crucial to inhibit MMP activities early and sufficiently to ensure BBB intact during ischaemia and reperfusion, but also to reduce side effects of MMP inhibitors to minimum. Recent advance in stroke therapy by thrombectomy could aid in such treatment with intra-arterially delivery of MMP inhibitors (and/or antioxidants).

Genetic and Epidemiological Similarities, and Differences Between Postoperative Intraperitoneal Adhesion Development and Other Benign Fibro-proliferative Disorders

Intraperitoneal adhesions complicate over half of abdominal-pelvic surgeries with immediate, short, and long-term sequelae of major healthcare concern. The pathogenesis of adhesion development is similar to the pathogenesis of wound healing in all tissues, which if unchecked result in production of fibrotic conditions. Given the similarities, we explore the published literature to highlight the similarities in the pathogenesis of intra-abdominal adhesion development (IPAD) and other fibrotic diseases such as keloids, endometriosis, uterine fibroids, bronchopulmonary dysplasia, and pulmonary, intraperitoneal, and retroperitoneal fibrosis. Following a literature search using PubMed database for all relevant English language articles up to November 2020, we reviewed relevant articles addressing the genetic and epidemiological similarities and differences in the pathogenesis and pathobiology of fibrotic diseases. We found genetic and epidemiological similarities and differences between the pathobiology of postoperative IPAD and other diseases that involve altered fibroblast-derived cells. We also found several genes and single nucleotide polymorphisms that are up- or downregulated and whose products directly or indirectly increase the propensity for postoperative adhesion development and other fibrotic diseases. An understanding of the similarities in pathophysiology of adhesion development and other fibrotic diseases contributes to a greater understanding of IPAD and these disease processes. At a very fundamental level, blocking changes in the expression or function of genes necessary for the transformation of normal to altered fibroblasts may curtail adhesion formation and other fibrotic disease since this is a prerequisite for their development. Similarly, applying measures to induce apoptosis of altered fibroblast may do the same; however, apoptosis should be at a desired level to simultaneously ameliorate development of fibrotic diseases while allowing for normal healing. Scientists may use such information to develop pharmacologic interventions for those most at risk for developing these fibrotic conditions.

Causal Effect of MMP-1 (Matrix Metalloproteinase-1), MMP-8, and MMP-12 Levels on Ischemic Stroke: A Mendelian Randomization Study

[Figure: see text].

Serum Levels of Matrix Metalloproteinase-1 in Brazilian Patients with Benign Prostatic Hyperplasia or Prostate Cancer

Metalloproteinases (MMPs) are involved in metastatic tumor processes, with changes in circulating levels detected in several cancer types. Here, we compare serum concentrations of metalloproteinase-1 (MMP-1) across individuals clinically diagnosed with prostate cancer (PCa) or benign prostatic hyperplasia (BPH), correcting results for the rs495366 single nucleotide polymorphism (SNP) that predisposes to differential MMP-1 levels. 196 men aged ≥50 years were followed at a university hospital urology outpatient clinic, with clinical, anthropometric, and rectal examinations performed by one urologist. Blood samples obtained prior to any clinical intervention provided baseline MMP-1 and total/free PSA levels as well as metabolic, hormonal, and inflammatory markers. The SNP was genotyped by real-time PCR. Participants with medical and/or laboratory profile compatible with malignancy composed the PCa group when confirmed by the Gleason scale. As expected, A-allele homozygotes showed reduced levels of MMP-1. Genotype-adjusted analyses revealed the mean MMP-1 level as 2-fold higher in PCa carriers compared to BPH patients. No other differences were found according to the prostatic condition or genotypic distribution, except for the expected raise in total and free PSA levels in PCa. In conclusion, increased serum levels of MMP-1 were observed in this context of prostatic malignancy compared to a benign phenotype, regardless of a genetic influence.

Targeting ELTD1, an angiogenesis marker for glioblastoma (GBM), also affects VEGFR2: molecular-targeted MRI assessment

Glioblastomas (GBM) are deadly brain tumors that currently do not have long-term patient treatments available. GBM overexpress the angiogenesis factor VEGF and its receptor VEGFR2. ETLD1 (epidermal growth factor, latrophilin and seven transmembrane domain-containing protein 1), a G-protein coupled receptor (GPCR) protein, we discovered as a biomarker for high-grade gliomas, is also a novel regulator of angiogenesis. Since it was established that VEGF regulates ELTD1, we wanted to establish if VEGFR2 is also associated with ELTD1, by targeted antibody inhibition. G55 glioma-bearing mice were treated with either anti-ELTD1 or anti-VEGFR2 antibodies. With the use of MRI molecular imaging probes, we were able to detect in vivo levels of either ELTD1 (anti-ELTD1 probe) or VEGFR2 (anti-VEGFR2 probe). Protein expressions were obtained for ELTD1, VEGF or VEGFR2 via immunohistochemistry (IHC). VEGFR2 levels were significantly decreased (P < 0.05) with anti-ELTD1 antibody treatment, and ELTD1 levels were significantly decreased (P < 0.05) with anti-VEGFR2 antibody treatment, both compared to untreated tumors. IHC from mouse tumor tissues established that VEGFR2 and ELTD1 were co-localized. The mouse anti-ELTD1 antibody treatment study indicated that anti-VEGFR2 antibody treatment does not significantly increase survival, decrease tumor volumes, or alter tumor perfusion (measured as relative cerebral blood flow or rCBF). Conversely, anti-ELTD1 antibody treatment was able to significantly increase animal survival (P < 0.01), decrease tumor volumes (P < 0.05), and reduce change in rCBF (P < 0.001), when compared to untreated or IgG-treated tumor bearing mice. Anti-ELTD1 antibody therapy could be beneficial in targeting ELTD1, as well as simultaneously affecting VEGFR2, as a possible GBM treatment.

Matrix Metalloproteinase-1 Gene Polymorphism Associated with Ultrasound-Assessed Carotid Thickness among Older Adults

BACKGROUND AND AIM

Due to the high incidence of vascular diseases, it is necessary to identify new circulating or structural markers for predicting risk for chronic diseases. Some studies suggest that MMP1 gene polymorphisms are associated with the enzyme expression levels in situ (e.g., in atherosclerotic plaques).

OBJECTIVES

Thus, the study of this polymorphism may help understanding the pathophysiology of coronary disease.

METHODS

We performed cross-sectional clinical and laboratory evaluations (including measurement of intima-media thickness of carotid arteries) and genotyping of the MMP1 SNP rs495366 (A/G) in 366 elderly people.

RESULTS

No significant differences between genotypes were noted for biochemical, metabolic, inflammatory, or clinical variables except for a significant difference in intima-media thickness for the left carotid artery and a trend toward significance for the right counterpart.

CONCLUSION

Carriers of the allele associated with lower MMP1 expression (allele A) presented greater carotid thickness. We suggest that the phenomenon can be explained by impaired remodeling of the arterial wall (poor degradation of collagen fibers in this scenario), yielding carotid wall thickening and a greater intrinsic risk for cerebrovascular events.

MMP 1 circulating levels and promoter polymorphism in risk prediction of coronary artery disease in asymptomatic first degree relatives

Coronary artery disease (CAD) remains to be the prominent health problem in India, and its incidence is growing in developing countries as well. Matrix metalloproteinase 1 (MMP 1) is highly expressed in disruption-prone shoulder regions of the fibrous plaques. The present study aims to investigate association of MMP 1 gene polymorphisms (-1607 1G/2G) and serum circulating levels with CAD. The study includes 300 CAD patients, 100 FDRS, and 300 controls. ELISA and PCR-RFLP were performed to determine MMP 1 serum levels and genotypes respectively. MMP1 levels were high in CAD patients, followed by FDRS compared to controls (2.15±1.2ng/ml; 1.46±1.04ng/ml and 0.96±0.53ng/ml) respectively. ROC analysis showed the AUC at 95% CI of serum MMP-1 to be 0.83 and 0.73-0.94, respectively. The optimal cut-off point (sensitivity; specificity) of serum MMP 1 was >1.5ng/ml (0.74; 0.90). The 2G/2G genotype was associated with high MMP 1 circulating levels in CAD patients, and a similar trend was observed in FDRS and controls. The pre-mRNA secondary structure of the 2G allele is much more stable than 1G allele. Our results suggest MMP 1 serum levels and polymorphism as potential independent prognostic markers for future cardiovascular events. These may also help to stratify CAD patients and to identify susceptibility for CAD in asymptomatic healthy FDRS.

Genetic analysis of emerging risk factors in coronary artery disease

BACKGROUND AND AIMS

Type 2 diabetes (T2D), low-density lipoprotein-cholesterol (LDL-c), body mass index (BMI), blood pressure and smoking are established risk factors that play a causal role in coronary artery disease (CAD). Numerous common genetic variants associating with these and other risk factors have been identified, but their association with CAD has not been comprehensively examined in a single study. Our goal was to comprehensively evaluate the associations of established and emerging risk factors with CAD using genetic variants identified from Genome-wide Association Studies (GWAS).

METHODS

We tested the effect of 60 traditional and putative risk factors with CAD, using summary statistics obtained in GWAS. We approximated the regression of a response variable onto an additive multi-SNP genetic risk score in the Coronary Artery DIsease Genomewide Replication And Meta-analysis (CARDIoGRAM) consortium dataset weighted by the effect of the SNP on the risk factors.

RESULTS

The strongest association with risk of CAD was for LDL-c SNPs (p = 3.96E-34). For non-established CAD risk factors, we found significant CAD associations for coronary artery calcification (CAC), Lp(a), LP-PLA2 activity, plaque, vWF and FVIII. In an attempt to identify independent associations between risk factors and CAD, only SNPs with an effect on the target trait were included. This identified CAD associations for Lp(a)(p = 1.77E-21), LDL-c (p = 4.16E-06), triglycerides (TG) (p = 1.94E-05), height (p = 2.06E-05), CAC (p = 3.13E-23) and carotid plaque (p = 2.08E-05).

CONCLUSIONS

We identified SNPs associated with the emerging risk factors Lp(a), TG, plaque, height and CAC to be independently associated with risk of CAD. This provides further support for-ongoing clinical trials of Lp(a) and TG, and suggests that CAC and plaque could be used as surrogate markers for CAD in clinical trials.

Serum levels of the proinflammatory cytokine interleukin-6 vary based on diagnoses in individuals with lumbar intervertebral disc diseases

BACKGROUND

Many intervertebral disc diseases cause low back pain (LBP). Proinflammatory cytokines and matrix metalloproteinases (MMPs) participate in disc pathology. In this study, we examined levels of serum cytokines and MMPs in human subjects with diagnoses of disc herniation (DH), spinal stenosis (SS), or degenerative disc disease (DDD) relative to levels in control subjects. Comparison between subjects with DH and those with other diagnoses (Other Dx, grouped from SS and DDD) was performed to elaborate a pathological mechanism based on circulating cytokine levels.

METHODS

Study participants were recruited from a spine neurosurgery practice (n = 80), a back pain management practice (n = 27), or a control cohort (n = 26). Serum samples were collected before treatment and were assayed by multiplex assays for levels of interleukin (IL)-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-13, interferon-γ, tumor necrosis factor-α, MMP-1, MMP-3, and MMP-9. Inflammatory and degradative mediator levels were compared for subjects with LBP and control subjects, by diagnosis and by treatment groups, controlling for effects of sex, age, and reported history of osteoarthritis. Spearman's correlation coefficient was used to examine relationships with age, body mass index (BMI), symptom duration, and smoking history.

RESULTS

Serum levels of IL-6 were significantly higher in subjects with LBP compared with control subjects. Participants with LBP due to Other Dx had significantly higher levels of IL-6 than DH and controls. Serum levels of MMP-1 were significantly lower in LBP subjects, specifically those with DH, than in control subjects. Positive correlations were found between IL-6 levels and BMI, symptom duration, and age. MMP-1 levels were positively correlated with age.

CONCLUSIONS

The findings of the present clinical study are the results of the first examination of circulating cytokine levels in DDD and SS and provide evidence for a more extensive role of IL-6 in disc diseases, where patients with DDD or SS have higher serum cytokine levels than those with DH or control subjects. These findings suggest that LBP subjects have low-grade systemic inflammation, and biochemical profiling of circulating cytokines may assist in refining personalized diagnoses of disc diseases.

Identification of a variant in KDR associated with serum VEGFR2 and pharmacodynamics of Pazopanib

PURPOSE

VEGF receptor (VEGFR) kinases are important drug targets in oncology that affect function of systemic endothelial cells. To discover genetic markers that affect VEGFR inhibitor pharmacodynamics, we performed a genome-wide association study of serum soluble vascular VEGFR2 concentrations [sVEGFR2], a pharmacodynamic biomarker for VEGFR2 inhibitors.

EXPERIMENTAL DESIGN

We conducted a genome-wide association study (GWAS) of [sVEGFR2] in 736 healthy Old Order Amish volunteers. Gene variants identified from the GWAS were genotyped serially in a cohort of 128 patients with advanced solid tumor with baseline [sVEGFR2] measurements, and in 121 patients with renal carcinoma with [sVEGFR2] measured before and during pazopanib therapy.

RESULTS

rs34231037 (C482R) in KDR, the gene encoding sVEGFR2 was found to be highly associated with [sVEGFR2], explaining 23% of the variance (P = 2.7 × 10(-37)). Association of rs34231037 with [sVEGFR2] was replicated in 128 patients with cancer with comparable effect size (P = 0.025). Furthermore, rs34231037 was a significant predictor of changes in [sVEGFR2] in response to pazopanib (P = 0.01).

CONCLUSION

Our findings suggest that genome-wide analysis of phenotypes in healthy populations can expedite identification of candidate pharmacogenetic markers. Genotyping for germline variants in KDR may have clinical utility in identifying patients with cancer with unusual sensitivity to effects of VEGFR2 kinase inhibitors.

Genome-wide association study of CSF levels of 59 alzheimer's disease candidate proteins: significant associations with proteins involved in amyloid processing and inflammation

Cerebrospinal fluid (CSF) 42 amino acid species of amyloid beta (Aβ42) and tau levels are strongly correlated with the presence of Alzheimer's disease (AD) neuropathology including amyloid plaques and neurodegeneration and have been successfully used as endophenotypes for genetic studies of AD. Additional CSF analytes may also serve as useful endophenotypes that capture other aspects of AD pathophysiology. Here we have conducted a genome-wide association study of CSF levels of 59 AD-related analytes. All analytes were measured using the Rules Based Medicine Human DiscoveryMAP Panel, which includes analytes relevant to several disease-related processes. Data from two independently collected and measured datasets, the Knight Alzheimer's Disease Research Center (ADRC) and Alzheimer's Disease Neuroimaging Initiative (ADNI), were analyzed separately, and combined results were obtained using meta-analysis. We identified genetic associations with CSF levels of 5 proteins (Angiotensin-converting enzyme (ACE), Chemokine (C-C motif) ligand 2 (CCL2), Chemokine (C-C motif) ligand 4 (CCL4), Interleukin 6 receptor (IL6R) and Matrix metalloproteinase-3 (MMP3)) with study-wide significant p-values (p<1.46×10⁻¹⁰) and significant, consistent evidence for association in both the Knight ADRC and the ADNI samples. These proteins are involved in amyloid processing and pro-inflammatory signaling. SNPs associated with ACE, IL6R and MMP3 protein levels are located within the coding regions of the corresponding structural gene. The SNPs associated with CSF levels of CCL4 and CCL2 are located in known chemokine binding proteins. The genetic associations reported here are novel and suggest mechanisms for genetic control of CSF and plasma levels of these disease-related proteins. Significant SNPs in ACE and MMP3 also showed association with AD risk. Our findings suggest that these proteins/pathways may be valuable therapeutic targets for AD. Robust associations in cognitively normal individuals suggest that these SNPs also influence regulation of these proteins more generally and may therefore be relevant to other diseases.

The use of quantitative endophenotypes from cerebrospinal fluid has led to the identification of several genetic variants that alter risk or rate of progression of Alzheimer's disease. Here we have analyzed the levels of 58 disease-related proteins in the cerebrospinal fluid for association with millions of variants across the human genome. We have identified significant, replicable associations with 5 analytes, Angiotensin-converting enzyme, Chemokine (C-C motif) ligand 2, Chemokine (C-C motif) ligand 4, Interleukin 6 receptor and Matrix metalloproteinase-3. Our results suggest that these variants play a regulatory role in the respective protein levels and are relevant to the inflammatory and amyloid processing pathways. Variants in associated with ACE and those associated with MMP3 levels also show association with risk for Alzheimer's disease in the expected directions. These associations are consistent in cerebrospinal fluid and plasma and in samples with only cognitively normal individuals suggesting that they are relevant in the regulation of these protein levels beyond the context of Alzheimer's disease.

Genetic variants associated with circulating MMP1 levels near matrix metalloproteinase genes on chromosome 11q21-22 in Taiwanese: interaction with obesity

BACKGROUND

MMP1 is implicated in the pathogenesis of atherothrombotic cardiovascular disease. We aimed to elucidate genetic determinants of inflammatory marker levels, including circulating MMP1, in Taiwanese, and their association with obesity.

METHODS

Five genetic polymorphisms around matrix metalloproteinase genes on chromosome 11q21-22 region were genotyped in 519 subjects.

RESULTS

After adjusting for clinical covariates, two polymorphisms were significantly associated with MMP1 levels, rs1799750 and rs495366, using an additive inheritance model (P = 1.5x10-4 and P = 2.57x10-5, respectively). Using dominant model, minor alleles of rs1799750 and rs495366 were associated with higher MMP1 levels (P = 1.3x10-4 and P = 1.95x10-5, respectively). In haplotype analysis, two haplotypes inferred from five SNPs (A2GATA and A1GATG) were associated with MMP1 levels (P = 5x10-4 and P = 8.47x10-5, respectively). Subgroup and interaction analysis revealed an association of rs1799750 and rs495366 with MMP1 levels only in non-obese subjects (P = 6.66x10-6 and P = 4.38x10-5, respectively, and interaction P = 0.008 for rs1799750). Haplotype interaction analysis also showed significant interaction for haplotype A1GATG (interaction P = 0.003).

CONCLUSIONS

Genotypes/haplotypes around MMP1 locus are associated with MMP1 levels in Taiwanese. Further, since genotypes/haplotypes near MMP1 locus interact with obesity to set MMP1 levels, genetic determinants for MMP1 level may be different between obese and non-obese individuals.

Genome-wide association study identifies TNFSF13 as a susceptibility gene for IgA in a South Chinese population in smokers

IgA is an important factor in our immune system. There are many diseases associated with it, such as IgA nephropathy, IgA deficiency, and so on. In order to describe the relationship between the genes and the IgA level, we performed a genome-wide association study of serum IgA with 1,999 healthy Chinese men in the first stage and replicated on an independent Chinese sample with 1,496 subjects in the second stage. Association between each SNP with IgA was estimated by multivariate linear regression analysis conditioned on age and smoke. Haplotype analysis for the block around the top SNP was performed. In the first stage, one genomic locus was identified to be significantly associated with IgA. The loci is TNFSF13 (17p13.1; rs3803800; P = 6.26 × 10(-8)). In smoke-specific analysis, rs3803800 was approximately significantly associated with IgA levels in smokers (P = 3.96 × 10(-7)), while no association was observed in nonsmokers (P = 2.28 × 10(-1)). In addition, we performed the haplotype analysis on chromosome 17 with the SNPs around rs3803800. Although the total P value for the haplotype did not acquire significant difference, three haplotypes (TGAG, CACG, and CACA) reached significant (P < 0.05). In conclusion, TNFSF13 could be a susceptible gene which was discovered having relationship with serum IgA level, and smoke might be a factor infecting the IgA level.

Functional gene polymorphism of matrix metalloproteinase-1 is associated with benign hyperplasia of myo- and endometrium in the Russian population

AIMS

Estrogen-dependent hyperplasia of myo- and endometrium manifests as uterine leiomyoma or adenomyosis. We studied possible associations between common polymorphisms of matrix metalloproteinase (MMP) genes and clinical features of uterine hyperplasia.

PATIENTS AND METHODS

One hundred seventy female patients with uterine leiomyoma (46.6±0.5 years) were observed. Clinical diagnosis was based on physical examination, ultrasonography, and histological data. MMP-1 (-1607 1G/2G, rs1799750) and MMP-3 (-1171 5A/6A, rs3025058) were genotyped with allele-specific polymerase chain reaction (PCR) of leukocyte DNA. Clinical and genetic data were evaluated using nonparametric statistics.

RESULTS

Distributions of MMP-1 and MMP-3 promoter alleles among patients and population controls were similar and corresponded to the Hardy-Weinberg equilibrium (HWE). Detectable tumor growth and adenomyosis were observed, respectively, in 71% and 55% of cases. Steady-state leiomyoma correlated with a higher prevalence of the MMP-1 1G/1G genotype (p=0.02 by χ(2) test). Accelerated tumor growth correlated with higher frequency of the MMP-1 2G allele [odds ratio (OR)=2.048, p=0.039, χ(2)=4.2611, confidence interval (CI)=(1.032-4.062)]. MMP-1 2G was also associated with multinodular growth [OR=3.561, p=0.01249, χ(2)=6.24, CI=(1.261-10.058)]. The MMP-1 2G allele tended to increase in patients with adenomyosis [OR=1.525, p=0.054, χ(2)=3.71, CI=(0.992-2.345)].

CONCLUSION

Our pilot study suggests that the 2G (-1607)MMP-1 genotype may be a potential risk marker of myo- and endometrial hyperplasia.

Genetic polymorphisms of matrix metalloproteinase 3 in primary sclerosing cholangitis

BACKGROUND

The damaging cholestasis inherent to primary sclerosing cholangitis (PSC) results from bile duct stricturing because of progressive fibrosis. The matrix metalloproteinase 3 (MMP3) degrades a wide range of matrix components and is expressed by activated liver stellate cells, and so is a candidate for involvement with the fibrotic processes underlying PSC. Moreover, the MMP3 gene harbours polymorphisms associated with variation in its activity directly impacting clinical phenotypes.

AIMS

We aimed to examine the influence of MMP3 polymorphisms on PSC risk and progression.

METHODS

Nine single nucleotide polymorphisms (SNPs) tagging the common genetic variation of MMP3 were genotyped in 266 PSC patients and 407 controls. SNPs and inferred haplotypes were assessed for PSC association by logistic regression and score tests. The effect of SNPs on survival to liver transplant or death was analysed using Cox regression, and Kaplan-Meier curves were constructed.

RESULTS

No association of PSC with individual SNPs or haplotypes of MMP3 was detected. However, progression to death or liver transplant was significantly associated with homozygosity for minor alleles of rs522616, rs650108 and rs683878, particularly among PSC patients with concurrent ulcerative colitis (UC) (strongest in redundant SNPs rs650108/rs683878, hazard ratio=3.23, 95% confidence interval 1.45-7.25, P=0.004).

CONCLUSIONS

Genetic variation in MMP3 influences PSC progression, possibly in the context of coexisting UC. While the functional variants and specific mechanisms remain unknown, this finding implicates the turnover of the extracellular matrix as an important and variable component of PSC pathogenesis. Efforts to understand this process could form the basis for developing effective treatments, which are currently lacking for PSC.