Faculty Bibliography

Background Psoriasis is an inflammatory disease of the skin associated with heightened cardiovascular (CV) disease. Serum levels of proprotein convertase subtilisin/kexin type 9 (PCSK9) associates with future CV risk and vascular dysfunction. We aimed to identify the relationship between pro-inflammatory pathways, circulating PCSK9, and vascular health in psoriasis. Methods Whole blood transcriptomics and serum proteomics was performed in 20 patients with psoriasis (mean age 42 +/- 14 years, 55% male, psoriasis area and severity index [PASI] 5 [3 - 11]) and 15 controls (mean age 41 +/- 14 years, 53% male) recruited into a clinical trial to assess vascular health in psoriasis (NCT03228017). Vascular health was assessed through flow mediated dilatation (FMD) and harvesting and analysis of brachial vein endothelial cells. Results Circulating PCSK9 was found to be 1.13-fold higher in psoriasis compared to controls (p=0.02) despite no difference in LDL-C (108 +/- 38 mg/dl vs. 90 +/- 25 mg/dl, respectively p=0.31). Circulating PCSK9 was correlated with psoriasis area severity index (PASI score, r=0.43, p=0.04) even after adjustment for age, gender, BMI and LDL-C (beta=0.02, p=0.03). Integration of the whole blood transcriptome yielded 322 transcripts which correlated with circulating PCSK9 (FDR<0.05). Network analysis of these transcripts highlighted interferon signaling (p=7.2x10^-6), a known pathogenic process in psoriasis, as a key regulator of PCSK9. Finally, circulating PCSK9 positively correlated with brachial vein endothelial expression of the pro-inflammatory transcripts CXCL10 (r=0.69, p<0.001), ICAM1 (r=0.49, p=0.02) and IL1beta (r=0.38, p<0.01) and inversely correlated with the functional measure of endothelial health, FMD (r=-0.52, p=0.03). Conclusion Circulating PCSK9 is elevated in psoriasis and associated with impaired vascular health. Analysis of the relationship between PCSK9 and systemic pathways revealed prominent interactions between PCSK9 and interferon signaling. Further research to better characterize these transcriptome and proteome variations and how it impacts vascular health in psoriasis may help elucidate new targets for therapeutic interventions.
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During obesity, macrophages infiltrate the visceral adipose tissue and promote inflammation that contributes to type II diabetes. Evidence suggests that the rewiring of cellular metabolism can regulate macrophage function. However, the metabolic programs that characterize adipose tissue macrophages (ATM) in obesity are poorly defined. Here, we demonstrate that ATM from obese mice exhibit metabolic profiles characterized by elevated glycolysis and oxidative phosphorylation, distinct from ATM from lean mice. Increased activation of HIF-1α in ATM of obese visceral adipose tissue resulted in induction of IL-1β and genes in the glycolytic pathway. Using a hypoxia-tracer, we show that HIF-1α nuclear translocation occurred both in hypoxic and non-hypoxic ATM suggesting that both hypoxic and pseudohypoxic stimuli activate HIF-1α and its target genes in ATM during diet-induced obesity. Exposure of macrophages to the saturated fatty acid palmitate increased glycolysis and HIF-1α expression, which culminated in IL-1β induction thereby simulating pseudohypoxia. Using mice with macrophage-specific targeted deletion of HIF-1α, we demonstrate the critical role of HIF-1α-derived from macrophages in regulating ATM accumulation, and local and systemic IL-1β production, but not in modulating systemic metabolic responses. Collectively, our data identify enhanced glycolysis and HIF-1α activation as drivers of low-grade inflammation in obesity.

The etiology of aortic aneurysms is poorly understood, but it is associated with atherosclerosis, hypercholesterolemia, and abnormal transforming growth factor β (TGF-β) signaling in smooth muscle. Here, we investigated the interactions between these different factors in aortic aneurysm development and identified a key role for smooth muscle cell (SMC) reprogramming into a mesenchymal stem cell (MSC)-like state. SMC-specific ablation of TGF-β signaling in Apoe^-/- mice on a hypercholesterolemic diet led to development of aortic aneurysms exhibiting all the features of human disease, which was associated with transdifferentiation of a subset of contractile SMCs into an MSC-like intermediate state that generated osteoblasts, chondrocytes, adipocytes, and macrophages. This combination of medial SMC loss with marked increases in non-SMC aortic cell mass induced exuberant growth and dilation of the aorta, calcification and ossification of the aortic wall, and inflammation, resulting in aneurysm development.

Neutrophil extracellular traps (NETs) promote inflammation and atherosclerosis progression. NETs are increased in diabetes and impair the resolution of inflammation during wound healing. Atherosclerosis resolution, a process resembling wound healing, is also impaired in diabetes. Thus, we hypothesized that NETs impede atherosclerosis resolution in diabetes by increasing plaque inflammation. Indeed, transcriptomic profiling of plaque macrophages from NET positive and negative areas in low-density lipoprotein receptor-deficient (Ldlr-/-) mice revealed inflammasome and glycolysis pathway upregulation, indicating a heightened inflammatory phenotype. We found that NETs decline during atherosclerosis resolution, which was induced by reducing hyperlipidemia in non-diabetic mice, but they persist in diabetes, exacerbating macrophage inflammation and impairing resolution. In diabetic mice deoxyribonuclease 1 (DNase1) treatment reduced plaque NETs content and macrophage inflammation, promoting atherosclerosis resolution after lipid-lowering. Given that humans with diabetes also exhibit impaired atherosclerosis resolution with lipid-lowering, these data suggest that NETs contribute to the increased cardiovascular disease risk in this population and are a potential therapeutic target.

OBJECTIVE:=0.02). CONCLUSIONS:In patients with psoriasis, platelets are activated and induce endothelial cell inflammation. Low-dose aspirin improved endothelial cell health in psoriasis via platelet COX-1 inhibition. These data demonstrate a previously unappreciated role of platelets in psoriasis and endothelial cell inflammation, which suggests that aspirin may be effective in improving vascular health in patients with psoriasis. Registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT03228017.

The development of potent cholesterol-reducing medications in the last decade of the twentieth century has altered the approach to prevention and treatment of cardiovascular disease (CVD). Initial experience with statins, and more recently with the addition of PCSK9 inhibitors, has proven that human CVD, like that in animal models, can be halted and regressed. Available clinical data show that the lower the achieved level of low-density lipoprotein cholesterol, the greater the regression of disease. Investigative studies are now aimed to understand those factors that both accelerate and impede this healing process. Some of these are likely to be modifiable, and the future of atherosclerotic CVD treatment is likely to be early screening, use of measures to repair atherosclerotic arteries, and prevention of most CVD events.

BACKGROUND:Cholesterol Efflux Capacity (CEC) is considered to be a key atheroprotective property of high-density lipoproteins (HDL). However, the role of HDL-CEC in atherosclerosis and cardiovascular (CV) risk is still controversial, and data in individuals with diabetes are limited. OBJECTIVE:In this study, we have investigated the relationship of CEC and other HDL characteristics with clinical and subclinical atherosclerosis in subjects with elevated cardiovascular diseases (CVD) risk and Type 2 Diabetes Mellitus (T2DM). METHODS:Using multiple linear regression analyses, we determined the relationship of HDL-CEC with carotid intima-media thickness (cIMT, Z-Score), an endothelial dysfunction (EnD) Score (Z-Score), prevalent CVD (n = 150 cases) and history of CV events (CVE, n = 85 cases) in an observational cohort (CODAM, n = 574, 59.6 ± 0.3 yr, 61.3% men, 24.4% T2DM). Stratified analyses were performed to determine if the associations differed between individuals with normal glucose metabolism (NGM) and those with disturbed glucose metabolism. RESULTS: = .074 and .034, respectively), but not in those with NGM. CONCLUSION/CONCLUSIONS:HDL-CEC is not associated with clinical or subclinical atherosclerosis, neither in the whole population nor in individuals with (pre)diabetes, while other HDL characteristics show atheroprotective associations. The atheroprotective associations of HDL-size and HDL-P are lost in (pre)diabetes, while higher concentrations of HDL-C and apoA-I are associated with a lower prevalence of CVD in (pre)diabetes.

We assessed the importance of triglyceride (TG) lipolysis and circulating HDL levels in the resolution of atherosclerosis and the phenotype of vascular macrophages. We hypothesized that hyperTG impairs atherosclerosis regression due to decreased HDL particle numbers (HDL-P) and/or HDL function assessed as Cholesterol Efflux Capacity (CEC). To study hyperTG, we performed atherosclerosis regression studies in control Lipoprotein lipase (LpL) flox (LpLfl/fl) and tamoxifen inducible LpL KO (iLpL-/-) mice; the latter showing plasma TG of ~500mg/dL after tamoxifen treatment. We used two different atherosclerosis regression models – the aortic transplant and inhibition of the LDL receptor (LDLR) using antisense oligonucleotides followed by re-expression after ASO discontinuation. We analyzed atherosclerosis regression (lesion size and CD68+ macrophages) in aortic arches, roots and branchiocephalic …

BACKGROUND:Tamoxifen is an oestrogen receptor modulator that is widely used for the treatment of early stage breast cancer and reduction of recurrences. Tamoxifen is also used as a powerful research tool for controlling gene expression in the context of the Cre/loxP site-specific recombination system in conditional mutant mice. METHODS:To determine whether the administration of tamoxifen affects Plasmodium growth and/or disease outcome in malaria, in vitro studies assessing the effect of tamoxifen and its active metabolite 4-hydroxytamoxifen on Plasmodium falciparum blood stages were performed. Tamoxifen effects were also evaluated in vivo treating C57/B6 mice infected with Plasmodium berghei (ANKA strain), which is the standard animal model for the study of cerebral malaria. RESULTS:Tamoxifen and its active metabolite, 4-hydroxytamoxifen, show activity in vitro against P. falciparum (16.7 to 5.8 µM IC50, respectively). This activity was also confirmed in tamoxifen-treated mice infected with P. berghei, which show lower levels of parasitaemia and do not develop signs of cerebral malaria, compared to control mice. Mice treated with tamoxifen for 1 week and left untreated for an additional week before infection showed similar parasitaemia levels and signs of cerebral malaria as control untreated mice. CONCLUSIONS:Tamoxifen and its active metabolite, 4-hydroxytamoxifen, have significant activity against the human parasite P. falciparum in vitro and the rodent parasite P. berghei in vivo. This activity may be useful for prevention of malaria in patients taking this drug chronically, but also represents a major problem for scientists using the conditional mutagenic Cre/LoxP system in the setting of rodent malaria. Allowing mice to clear tamoxifen before starting a Plasmodium infection allows the use the Cre/LoxP conditional mutagenic system to investigate gene function in specific tissues.