The neuregulin-1 (NRG-1)/receptor tyrosine-protein kinase erbB (ErbB) system is an endothelium-controlled paracrine system modulating cardiac performance and adaptation. Recent studies have indicated ...that NRG-1 has antifibrotic effects in the left ventricle, which were explained by direct actions on cardiac fibroblasts. However, the NRG-1/ErbB system also regulates the function of macrophages. In this study, we hypothesized that the antifibrotic effect of NRG-1 in the heart is at least partially mediated through inhibitory effects on macrophages. We also hypothesized that the antifibrotic effect of NRG-1 may be active in other organs, such as the skin and lung. First, in a mouse model of angiotensin II (ANG II)-induced myocardial hypertrophy and fibrosis, NRG-1 treatment (20 µg·kg
·day
ip) significantly attenuated myocardial hypertrophy and fibrosis and improved passive ventricular stiffness (4 wk). Interestingly, 1 wk after exposure to ANG II, NRG-1 already attenuated myocardial macrophage infiltration and cytokine expression. Furthermore, mice with myeloid-specific deletion of the
gene (
) showed an intensified myocardial fibrotic response to ANG II. Consistently, NRG-1 activated the ErbB4 receptor in isolated macrophages, inhibited phosphatidylinositide 3-kinase/Akt and STAT3 signaling pathways, and reduced the release of inflammatory cytokines. Further experiments showed that the antifibrotic and anti-inflammatory effects of NRG-1 were reproducible in mouse models of bleomycin-induced dermal and pulmonary fibrosis. Overall, this study demonstrates that the antifibrotic effect of NRG-1 in the heart is linked to anti-inflammatory activity NRG-1/ErbB4 signaling in macrophages. Second, this study shows that NRG-1 has antifibrotic and anti-inflammatory effects in organs other than the heart, such as the skin and lung.
Our study contributes to the understanding of the antifibrotic effect of neuregulin-1 during myocardial remodeling. Here, we show that the antifibrotic effect of neuregulin-1 is at least partially mediated through anti-inflammatory activity, linked to receptor tyrosine-protein kinase erbB-4 activation in macrophages. Furthermore, we show that this effect is also present outside the heart.
Acetylsalicylic acid (ASA) is widely used in secondary prevention of cardiovascular (CV) disease, mainly because of its antithrombotic effects. Here, we investigated whether ASA can prevent the ...progression of vessel wall remodelling, atherosclerosis, and CV complications in apolipoprotein E deficient (
) mice, a model of stable atherosclerosis, and in
mice with a mutation in the fibrillin-1 gene (
), which is a model of elastic fibre fragmentation, accompanied by exacerbated unstable atherosclerosis. Female
and
mice were fed a Western diet (WD). At 10 weeks of WD, the mice were randomly divided into four groups, receiving either ASA 5 mg/kg/day in the drinking water (
(
= 14),
(
= 19)) or plain drinking water (
(
= 15),
(
= 21)) for 15 weeks.
mice showed an increased neutrophil-lymphocyte ratio (NLR) compared to
mice, and this effect was normalised by ASA. In the proximal ascending aorta wall, ASA-treated
mice showed less p-SMAD2/3 positive nuclei, a lower collagen percentage and an increased elastin/collagen ratio, consistent with the values measured in
mice. ASA did not affect plaque progression, incidence of myocardial infarction and survival of
mice, but systolic blood pressure, cardiac fibrosis and hypertrophy were reduced. In conclusion, ASA normalises the NLR, passive wall stiffness and cardiac remodelling in
mice to levels observed in
mice, indicating additional therapeutic benefits of ASA beyond its classical use.
Increased evidence suggests a pro-atherogenic role for conventional dendritic cells (cDC). However, due to the lack of an exclusive marker for cDC, their exact contribution to atherosclerosis remains ...elusive. Recently, a unique transcription factor was described for cDC, namely Zbtb46, enabling us to selectively target this cell type in mice.
Low-density lipoprotein receptor-deficient (Ldlr-/-) mice were transplanted with bone marrow from Zbtb46-diphtheria toxin receptor (DTR) transgenic mice following total body irradiation. Zbtb46-DTR→Ldlr-/- chimeras were fed a Western-type diet for 18 weeks while cDC were depleted by administering diphtheria toxin (DT).
Although we confirmed efficient direct induction of cDC death in vitro and in vivo upon DT treatment of Zbtb46-DTR mice, advanced atherosclerotic plaque size and composition was not altered. Surprisingly, however, analysis of Zbtb46-DTR→Ldlr-/- chimeras showed that depletion of cDC was not sustained following 18 weeks of DT treatment. In contrast, high levels of anti-DT antibodies were detected.
Because of the observed generation of anti-DT antibodies and consequently the partial depletion of cDC, no clear decision can be taken on the role of cDC in atherosclerosis. Our results underline the unsuitability of Zbtb46-DTR→Ldlr-/- mice for studying the involvement of cDC in maintaining the disease process of atherosclerosis, as well as of other chronic inflammatory diseases.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Atherosclerosis remains the leading cause of death in Western countries. Dipeptidyl peptidase (DPP) 4 has emerged as a novel target for the prevention and treatment of atherosclerosis. Family members ...DPP8 and 9 are abundantly present in macrophage-rich regions of atherosclerotic plaques, and DPP9 inhibition attenuates activation of human M1 macrophages
in vitro
. Studying this family in a mouse model for atherosclerosis would greatly advance our knowledge regarding their potential as therapeutic targets. We found that DPP4 is downregulated during mouse monocyte-to-macrophage differentiation. DPP8 and 9 expression seems relatively low in mouse monocytes and macrophages. Viability of primary mouse macrophages is unaffected by DPP4 or DPP8/9 inhibition. Importantly, DPP8/9 inhibition attenuates macrophage activation as IL-6 secretion is significantly decreased. Mouse macrophages respond similarly to DPP inhibition, compared to human macrophages. This shows that the mouse could become a valid model species for the study of DPPs as therapeutic targets in atherosclerosis.
Atherosclerosis remains the leading cause of death and disability in our Western society. To investigate whether the dynamics of leukocyte (sub)populations could be predictive for plaque inflammation ...during atherosclerosis, we analyzed innate and adaptive immune cell distributions in blood, plaques, and lymphoid tissue reservoirs in apolipoprotein E-deficient (ApoE−/−) mice and in blood and plaques from patients undergoing endarterectomy. Firstly, there was predominance of the CD11b+ conventional dendritic cell (cDC) subset in the plaque. Secondly, a strong inverse correlation was observed between CD11b+ cDC or natural killer T (NKT) cells in blood and markers of inflammation in the plaque (including CD3, T-bet, CCR5, and CCR7). This indicates that circulating CD11b+ cDC and NKT cells show great potential to reflect the inflammatory status in the atherosclerotic plaque. Our results suggest that distinct changes in inflammatory cell dynamics may carry biomarker potential reflecting atherosclerotic lesion progression. This not only is crucial for a better understanding of the immunopathogenesis but also bares therapeutic potential, since immune cell-based therapies are emerging as a promising novel strategy in the battle against atherosclerosis and its associated comorbidities. The cDC-NKT cell interaction in atherosclerosis serves as a good candidate for future investigations.
Neoadjuvant immunotherapies hold promise in muscle-invasive bladder cancer (MIBC).
To report on 2-yr disease-free (DFS) and overall (OS) survival including novel tissue-based biomarkers and ...circulating tumor DNA (ctDNA) in the ABACUS trial.
ABACUS was a multicenter, single-arm, neoadjuvant, phase 2 trial, including patients with MIBC (T2-4aN0M0) who were ineligible for or refused neoadjuvant cisplatin-based chemotherapy.
Two cycles of atezolizumab were given prior to radical cystectomy. Serial tissue and blood samples were collected.
The primary endpoints of pathological complete response (pCR) rate and dynamic changes to T-cell biomarkers were published previously. Secondary outcomes were 2-yr DFS and OS. A biomarker analysis correlated with relapse-free survival (RFS) was performed, which includes FOXP3, major histocompatibility complex class I, CD8/CD39, and sequential ctDNA measurements.
The median follow-up time was 25 mo (95% confidence interval CI 25-26). Ninety-five patients received at least one cycle of atezolizumab. Eight patients did not undergo cystectomy (only one due to disease progression). The pCR rate was 31% (27/88; 95% CI 21-41). Two-year DFS and OS were 68% (95% CI 58-76) and 77% (95% CI 68-85), respectively. Two-year DFS in patients achieving a pCR was 85% (95% CI 65-94). Baseline PD-L1 and tumor mutational burden did not correlate with RFS (hazard ratio HR 0.60 95% CI 0.24-1.5, p = 0.26, and 0.72 95% CI 0.31-1.7, p = 0.46, respectively). RFS correlated with high baseline stromal CD8+ (HR 0.25 95% CI 0.09-0.68, p = 0.007) and high post-treatment fibroblast activation protein (HR 4.1 95% CI 1.3-13, p = 0.01). Circulating tumor DNA positivity values at baseline, after neoadjuvant therapy, and after surgery were 63% (25/40), 47% (14/30), and 14% (five/36), respectively. The ctDNA status was highly prognostic at all time points. No relapses were observed in ctDNA-negative patients at baseline and after neoadjuvant therapy. The lack of randomization and exploratory nature of the biomarker analysis are limitations of this work.
Neoadjuvant atezolizumab in MIBC is associated with clinical responses and high DFS. CD8+ expression and serial ctDNA levels correlated with outcomes, and may contribute to personalized therapy in the future.
We showed that bladder cancer patients receiving immunotherapy followed by cystectomy have good long-term outcomes. Furthermore, we found that certain biological features can predict patients who might have particular benefit from this therapy.
Abstract Vulnerable atherosclerotic plaques are prone to plaque rupture leading to acute cardiovascular syndromes and death. Elucidating the risk of plaque rupture is important to define better ...therapeutic or preventive strategies. In the present study, we investigated the effect of chronic intermittent mental stress on atherosclerotic plaque stability and cardiovascular mortality in apolipoprotein E-deficient (ApoE−/− ) mice with a heterozygous mutation in the fibrillin-1 gene (Fbn1C1039G+/− ). This mouse model displays exacerbated atherosclerosis with spontaneous plaque ruptures, myocardial infarction and sudden death, when fed a Western-type diet (WD). Female ApoE−/− Fbn1C1039G+/− mice were fed a WD for up to 25 weeks. After 10 weeks WD, mice were divided in a control (n = 27) and mental stress (n = 29) group. The chronic intermittent mental stress protocol consisted of 3 triggers: water avoidance, damp bedding and restraint stress, in a randomly assigned order lasting 6 h every weekday for 15 weeks. Chronic intermittent mental stress resulted in a significant increase in the amount of macrophages in atherosclerotic plaques of the proximal ascending aorta, whereas type I collagen and fibrous cap thickness were decreased. The coronary arteries of mental stress-treated mice showed larger plaques, more stenosis, and an increased degree of perivascular fibrosis. Moreover, myocardial infarctions occurred more frequently in the mental stress group. As compared to the control group, the survival of stressed ApoE−/− Fbn1C1039G+/− mice decreased from 67% to 52% at 25 weeks WD, presumably due to myocardial infarctions. In conclusion, chronic intermittent mental stress promotes plaque instability, myocardial infarctions, and mortality of ApoE−/− Fbn1C1039G+/− mice.
Abstract Autoimmune diseases affect about one in 15 individuals in developed countries and are characterized by a breakdown in immune tolerance. Current therapeutic approaches against destructive ...immune responses in autoimmune diseases are based on non-specific agents systemically suppressing the function of many immune effector cells. This indiscriminate immunosuppression, however, often causes serious and sometimes life-threatening side effects. Therefore, the need for more specific treatments resulting in lower toxicity and longer-term solutions is high. Because of the established role of dendritic cells (DCs) in maintaining the balance between immunity and tolerance, tolerogenic (tol)DCs might be novel therapeutic targets to prevent undesirable (auto-)immune responses. The idea behind tolDC therapy is that it is a highly targeted, antigen-specific treatment that only affects the auto-reactive inflammatory response. The therapeutic potential of tolDCs has already been proven in experimental animal models of different autoimmune disorders as well as with in vitro experiments using ex vivo generated human tolDCs, thus the challenge remains in bringing tolDC therapy to the clinic, although first clinical trials have been conducted. In this review, we will extensively discuss the use of tolDCs for induction of antigen-specific tolerance in several autoimmune disease settings, from bench to bedside, including currently applied strategies to generate tolDCs as well as technical difficulties and challenges in the field.
Abstract Because cholesterol-independent effects of statins are difficult to determine in patients, we studied these pleiotropic effects in apolipoprotein E-deficient (ApoE−/− ) mice with a mutation ...in the fibrillin-1 gene (Fbn1 C1039G +/− ). These mice develop exacerbated atherosclerosis and spontaneous plaque ruptures, accompanied by myocardial infarctions (MI) and sudden death. ApoE−/− Fbn1 C1039G +/− mice were fed a Western diet (WD). At week 10 of WD, mice were divided in a control (WD), atorvastatin (10 mg/kg/day + WD) and cholesterol withdrawal group (cholW, normal chow). The latter was included to compare the effects of atorvastatin with dietary lipid lowering. Fifteen weeks later, the mice were sacrificed. CholW, but not atorvastatin, reduced plasma cholesterol. Survival increased from 50% to 90% both in cholW and atorvastatin treated mice. CholW as well as atorvastatin treatment increased plaque collagen and fibrous cap thickness, but they did not affect the amount of plaque macrophages and T cells. MMP-2 and MMP-9 activity was significantly lower and the expression of MMP-12, TNF-α and IL-1β was strongly reduced in both treatment groups. Blood monocytes and neutrophils returned to baseline levels (ApoE−/− mice before the onset of atherosclerosis). Importantly, atorvastatin but not cholW significantly reduced coronary stenosis (from 50 to 28%) and the occurrence of MI (from 43 to 10%). In conclusion, independent of cholesterol lowering, atorvastatin significantly reduced mortality, plaque vulnerability and inflammation to the same extent as cholW. In addition, atorvastatin but not cholW reduced coronary stenosis and the occurrence of MI. These data unequivocally illustrate the significance of the pleiotropic effects of atorvastatin in the prevention of cardiovascular morbidity and mortality.
Different immune cell types are present within atherosclerotic plaques. Dendritic cells (DC) are of special interest, since they are considered as the ‘center of the immuniverse’. Identifying ...inflammatory DC subtypes within plaques is important for a better understanding of the lesion pathogenesis and pinpoints their contribution to the atherosclerotic process. We have developed a flow cytometry-based method to characterize and isolate different DC subsets (i.e. CD11b+, Clec9A+ and CD16+ conventional (c)DC and CD123+ plasmacytoid (p)DC) in human atherosclerotic plaques. We revealed a predominance of pro-inflammatory CD11b+ DC in advanced human lesions, whereas atheroprotective Clec9A+ DC were almost absent. CD123+ pDC and CD16+ DC were also detectable in plaques. Remarkably, plaques from distinct anatomical locations exhibited different cellular compositions: femoral plaques contained less CD11b+ and Clec9A+ DC than carotid plaques. Twice as many monocytes/macrophages were observed compared to DC. Moreover, relative amounts of T cells/B cells/NK cells were 6 times as high as DC numbers.
For the first time, fluorescent activated cell sorting analysis of DC subsets in human plaques indicated a predominance of CD11b+ cDC, in comparison with other DC subsets. Isolation of the different subsets will facilitate detailed functional analysis and may have significant implications for tailoring appropriate therapy.
•Understanding the origin/function of DC subsets that control atherogenesis is needed.•It can open up strategies to interfere with DC subset differentiation and functions for developing therapeutic targets.•FACS allowed us to characterize the presence of specialized DC subsets in human atherosclerotic lesions.•FACS analysis of carotid and femoral arteries revealed a predominance of the CD11bpos subset.•Also, different locations in the vascular tree show differences in the accumulation of specialized DC subsets.
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