Abstract The neuregulin-1 (NRG1)/ERBB4 signaling pathway has emerged as a cardioprotective pathway and is a promising target for the treatment of chronic heart failure. Activation of ERBB4 signaling is known to decrease cardiomyocyte cell death and hypertrophy, and fibroblast collagen synthesis. Recombinant NRG1 (rNRG1) is currently tested in phase III clinical trials for heart failure, but its need for intravenous administration is a disadvantage. In an attempt to circumvent this, we hypothesized that small-molecule-induced activation of ERBB4 is feasible and would recapitulate the effects of its natural ligand on myocytes and fibroblasts. To this end, we screened 10,240 compounds for their ability to induce homodimerization of ERBB4. We identified a series of 8 similar compounds (named EF-1 – EF-8) that concentration-dependently induced ERBB4 dimerization, with EF-1 being the most potent and effective compound (n = 4-5 independent repeats in each group; Emax = 27.9 ± 4.8% relative to NRG1, EC50 = 10.5 ± 4.5 x 10-6). EF-1 showed neither cytotoxicity nor increased cell proliferation of tumor cell lines. In vitro, EF-1 significantly decreased in a concentration-dependent manner hydrogen peroxide–induced cardiomyocyte cell death (n = 4 independent repeats in each group; P<0.0001 compared to siERBB4, Fig. 1A), angiotensin-II (AngII)-induced cardiomyocyte hypertrophy (n = 20 individual cardiomyocytes in each group; P<0.0001 compared to AngII/vehicle, Fig. 1B), and collagen expression in cultured human fibroblasts (n = 3 independent repeats in each group; P=0.03 compared to siERBB4, Fig. 1C). The observed effects in cultured cardiomyocytes and fibroblasts could be abrogated by siRNA targeting ERBB4, indicating that they were mediated by ERBB4. Moreover, when used in vivo, EF-1 (2 mg/kg/day) significantly decreased AngII-induced left ventricular Col1a1 and Col3a1 mRNA expression (n = 4-5 mice in each group; P=0.02 and P=0.004 compared to AngII/vehicle, respectively) and inhibited AngII-induced myocardial total and interstitial fibrosis in wild-type mice (n = 4-5 mice in each group, Fig. 2), but not in Erbb4-null mice. Moreover, EF-1 decreased acute cardiotoxicity (assessed by troponin release) in wild-type mice treated with doxorubicin (DOX; n = 8-9 mice in each group; P<0.0001 compared to DOX/vehicle), but not in Erbb4-null mice. In conclusion, we show that small-molecule-induced ERBB4 dimerization and activation is feasible, and recapitulates anti-fibrotic and cardiomyocyte protective effects in the heart in an ERBB4-dependent manner, both in vitro and in vivo. This could be the start for the further development of small-molecule ERBB4 agonists as a novel class of drugs to treat heart failure. Cardiomyocyte-protective effect in vitroAnti-fibrotic effect in vivo
Abstract Wastewater-based epidemiology could be applied to track down SARS-CoV-2 outbreaks at high spatio-temporal resolution and could potentially be used as an early-warning for emergence of SARS-CoV-2 circulation in the general population. Epidemiological surveillance of SARS-CoV-2 could play a role in monitoring the spread of the virus in the population and controlling possible outbreaks. However, sensitive sample preparation and detection methods are necessary to detect trace levels of SARS-CoV-2 RNA in influent wastewater (IWW). Unlike predecessors, method development of a SARS-CoV-2 RNA concentration and detection procedure was performed with IWW samples with high viral SARS-CoV-2 loads (in combination with seeding IWW with a surrogate coronavirus). This is of importance since the SARS-CoV-2 genome in IWW might have already been subject to in-sewer degradation into smaller genome fragments or might be present in a different form (e.g. cell debris,…). Centricon Plus-70 (100 kDa) centrifugal filter devices resulted in the lowest and most reproducible Ct-values for SARS-CoV-2 RNA. Lowering pore sizes did not improve our limit of detection and quantification. Real-time polymerase chain reaction (qPCR) was employed for the amplification of the N1, N2, N3 and E_Sarbeco-gene. This is one of the first studies to apply digital polymerase chain reaction (dPCR) for the detection of SARS-CoV-2 RNA in IWW. Interestingly, qPCR results were comparable with dPCR results suggesting that qPCR is a valid method. In this study, dPCR was also used as a proxy to assess the precision of qPCR. In this light, dPCR showed high variability at low concentration levels (10 0 copies/µL), indicating that variability in bioanalytical assays for SARS-CoV-2 RNA might be substantial. On average, the N2-gene showed high in-sample stability in IWW for 10 days of storage at 4 °C. Between-sample variability was substantial due to the low native concentrations in IWW. Additionally, the E-gene proved to be less stable compared to the N2-gene and showed higher variability. Freezing the IWW samples resulted in a 10-fold decay of loads of the N2- and E-gene in IWW. Although WBE can already aid in filling some knowledge gaps in the epidemiological surveillance of SARS-CoV-2, future WBE studies should aim to further validate and standardize bioanalytical assays, especially with regards to methodological limitations. Highlights Development of an analytical procedure for detection of SARS-CoV-2 RNA in wastewater Extraction recovery was evaluated in influent wastewater Precision measured with dPCR used as a proxy for qPCR qPCR of the N2 gene fragment showed high in-sample stability of SARS-CoV-2 on average
Abstract Background Coronary microvascular dysfunction (CMD) participates in the pathophysiology of multiple cardiovascular diseases, but treatment options are limited. A new treatment option may include ERBB4 stimulation by neuregulin-1 (NRG1), which has anti-inflammatory, antifibrotic, and cardioprotective effects in models of heart failure. Objectives To assess the effect NRG1/ERBB4 stimulation on CMD in hypertensive heart disease. Methods Hypertensive heart disease was induced in 12 Aachener minipigs by implantation of deoxycorticosterone acetate (DOCA) pellets for 8 weeks and compared to 6 controls. The DOCA pigs were randomized to a weekly infusion of JK07, a NRG1 fusion protein with improved pharmacokinetic and pharmacodynamic properties, or vehicle. Microvascular resistance was measured using the bolus thermodilution method. Results DOCA significantly increased microvascular resistance compared to controls (from 14.5 to 19.9 mmHg.s, p = 0.028). This increase was abrogated by JK07 (11.3 mmHg.s, p = 0.018 vs DOCA). dP/dtmax increased by DOCA compared to controls (from 2415.5 to 4455.5 mmHg/s, p = 0.011), which was also abrogated by JK07 (3107.3 mmHg/s, p = 0.055 vs DOCA). Interstitial left ventricular fibrosis was significantly lower in JK07-treated pigs compared to DOCA only (2.1 vs. 5.4 %, p = 0.026), but without difference in perivascular fibrosis (p = 0.48). JK07 did not affect myocyte cross-sectional area, capillary density, pericyte coverage, or microvascular vessel thickness. Conclusions ERBB4 activation by JK07 is capable to prevent CMD in a DOCA hypertensive pig model. Functional rather than structural alterations may explain the protective effects of JK07 on microvascular resistance.Visual summaryJK07 decreases microvascular resistance
Abstract Heart failure is a common and deadly disease, requiring new therapeutic approaches. The neuregulin-1 (NRG1)/erythroblastic leukemia viral oncogene homolog 4 (ERBB4) pathway is an interesting target because of its cardioprotective effects. The therapeutic use of recombinant NRG1 has been difficult, because it requires intravenous administration and is non-selective for the ERBB4 receptor. Moreover, development of small-molecule agonists of receptor dimers is generally considered to be challenging. Here, we hypothesized that small-molecule-induced activation of ERBB4 is feasible and can protect against myocardial cell death and fibrosis. To this end, we screened 10,240 compounds for their ability to induce homodimerization of ERBB4. We identified a series of 8 structurally similar compounds (named EF-1 – EF-8) that concentration-dependently induced ERBB4 dimerization, with EF-1 being the most potent. EF-1 decreased in an ERBB4-dependent manner cell death and hypertrophy in cultured atrial cardiomyocytes and collagen production in cultured human cardiac fibroblasts. EF-1 also inhibited angiotensin-II (AngII)-induced myocardial fibrosis in wild-type mice, but not in Erbb4-null mice. Additionally, EF-1 decreased troponin release in wild-type mice treated with doxorubicin (DOX), but not in Erbb4-null mice. Finally, EF-1 improved cardiac function in a mouse model of myocardial infarction (MI). In conclusion, we show that small-molecule-induced ERBB4 activation is possible, displaying anti-fibrotic and cardiomyocyte protective effects in the heart. This study can be the start for the development of small-molecule ERBB4 agonists as a novel class of drugs to treat heart failure.
Abstract Heart failure is a common and deadly disease requiring new treatments. The neuregulin-1/ERBB4 pathway offers cardioprotective benefits, but using recombinant neuregulin-1 as therapy has limitations due to the need for intravenous delivery and lack of receptor specificity. We hypothesize that small-molecule activation of ERBB4 could protect against heart damage and fibrosis. To test this, we conduct a screening of 10,240 compounds and identify eight structurally similar ones (EF-1 to EF-8) that induce ERBB4 dimerization, with EF-1 being the most effective. EF-1 reduces cell death and hypertrophy in cardiomyocytes and decreases collagen production in cardiac fibroblasts in an ERBB4-dependent manner. In wild-type mice, EF-1 inhibits angiotensin-II-induced fibrosis in males and females and reduces heart damage caused by doxorubicin and myocardial infarction in females, but not in Erbb4-null mice. This study shows that small-molecule ERBB4 activation is feasible and may lead to a novel class of drugs for treating heart failure.
Since the beginning of the COVID-19 pandemic, the wastewater-based epidemiology (WBE) of SARS-CoV-2 has been used as a complementary indicator to follow up on the trends in the COVID-19 spread in Belgium and in many other countries. To further develop the use of WBE, a multiplex digital polymerase chain reaction (dPCR) assay was optimized, validated and applied for the measurement of emerging SARS-CoV-2 variants of concern (VOC) in influent wastewater (IWW) samples. Key mutations were targeted in the different VOC strains, including SΔ69/70 deletion, N501Y, SΔ241 and SΔ157. The presented bioanalytical method was able to distinguish between SARS-CoV-2 RNA originating from the wild-type and B.1.1.7, B.1.351 and B.1.617.2 variants. The dPCR assay proved to be sensitive enough to detect low concentrations of SARS-CoV-2 RNA in IWW since the limit of detection of the different targets ranged between 0.3 and 2.9 copies/µL. This developed WBE approach was applied to IWW samples originating from different Belgian locations and was able to monitor spatio-temporal changes in the presence of targeted VOC strains in the investigated communities. The present dPCR assay developments were realized to bring added-value to the current national WBE of COVID-19 by also having the spatio-temporal proportions of the VoC in presence in the wastewaters.
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