Site-Specific Dual Labeling of Proteins on Cysteine Residues with Chlorotetrazines

International audienceDual-labeled biomolecules constitute a new generation of bioconjugates with promising applications in therapy and diagnosis. Unfortunately, the development of these new families of biologics is hampered by the technical difficulties associated with their construction. In particular, the site specificity of the conjugation is critical as the number and position of payloads can have a dramatic impact on the pharmacokinetics of the bioconjugate. Herein, we introduce dichlorotetrazine as a trivalent platform for the selective double modification of proteins on cysteine residues. This strategy is applied to the dual labeling of albumin with a macrocyclic chelator for nuclear imaging and a fluorescent probe for fluorescence imaging

Positron Emission Tomography Imaging of Neurotensin Receptor-Positive Tumors with 68 Ga-Labeled Antagonists: The Chelate Makes the Difference Again

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Cherenkov luminescence imaging is a fast and relevant preclinical tool to assess tumour hypoxia in vivo

Abstract Purpose Molecular imaging techniques visualise biomarkers for both drug development and personalised medicine. In this field, Cherenkov luminescence imaging (CLI) seems to be very attractive by allowing imaging with clinical PET radiotracers with high-throughput capabilities. In this context, we developed a fast CLI method to detect tumour hypoxia with 18F-fluoromisonidazole (FMISO) for drug development purposes. Methods Colon cancer model was induced in mice by subcutaneous injection of 1 × 106 CT-26 cells. FMISO was injected, and simultaneous PET-blood oxygen level dependent (BOLD)-MRI followed by CLI were performed along with immunohistochemistry staining with pimonidazole. Results There was a significant correlation between FMISO PET and CLI tumour uptakes, consistent with the BOLD-MRI mapping. Tumour-to-background ratio was significantly higher for CLI compared with PET and MRI. Immunohistochemistry confirmed tumour hypoxia. The imaging workflow with CLI was about eight times faster than the PET-MRI procedure. Conclusion CLI is a fast and relevant tool to assess tumour hypoxia. This approach could be particularly interesting for hypoxia-targeting drug development

[123I]MIBG is a better early marker of anthracycline cardiotoxicity than [18F]FDG: a preclinical SPECT/CT and simultaneous PET/MR study

International audienceAbstract Background During anthracycline treatment of cancer, there is a lack for biomarkers of cardiotoxicity besides the cardiac dysfunction. The objective of the present study was to compare [ 18 F]FDG and [ 123 I]MIBG (metaiodobenzylguanidine) in a longitudinal study in a doxorubicin-induced cardiotoxicity rat model. Methods Male Wistar Han rats were intravenously administered 3 times at 10 days’ interval with saline or doxorubicin (5 mg/kg). [ 123 I]MIBG SPECT/CT (single photon emission computed tomography-computed tomography) and simultaneous [ 18 F]FDG PET (positron emission tomography)/7 Tesla cardiac MR (magnetic resonance) imaging acquisitions were performed at 24 h interval before first doxorubicin / saline injection and every 2 weeks during 6 weeks. At 6 weeks, the heart tissue was collected for histomorphometry measurements. Results At week 4, left ventricle (LV) end-diastolic volume was significantly reduced in the doxorubicin group. At week 6, the decreased LV end-diastolic volume was maintained, and LV end-systolic volume was increased resulting in a significant reduction of LV ejection fraction (47 ± 6% vs. 70 ± 3%). At weeks 4 and 6, but not at week 2, myocardial [ 18 F]FDG uptake was decreased compared with the control group (respectively, 4.2 ± 0.5%ID/g and 9.2 ± 0.8%ID/g at week 6). Moreover, [ 18 F]FDG cardiac uptake correlated with cardiac function impairment. In contrast, from week 2, a significant decrease of myocardial [ 123 I]MIBG heart to mediastinum ratio was detected in the doxorubicin group and was maintained at weeks 4 and 6 with a 45.6% decrease at week 6. Conclusion This longitudinal study precises that after doxorubicin treatment, cardiac [ 123 I]MIBG uptake is significantly reduced as early as 2 weeks followed by the decrease of the LV end-diastolic volume and [ 18 F]FDG uptake at 4 weeks and finally by the increase of LV end-systolic volume and decrease of LV ejection fraction at 6 weeks. Cardiac innervation imaging should thus be considered as an early key feature of anthracycline cardiac toxicity

Analyse des effets direct et indirect des pratiques agricoles sur les adventices et la production de blé tendre d’hiver

SPEEAGESTADAGROSUPINRAAnalysis of direct and indirect effects of farming practices on weeds and winter wheat yield. Farmers implement farming practices to maximize production by limiting biotic (e.g. weeds) and abiotic (e.g. nutrient) growth factors. Our study aimed to quantify direct and indirect (through a change of weed pressure) effects of farming practices on yield. We analysed the relationships between farming practices, weeds and yield of 152 wheat fields located in the study site of Fénay (UMR Agroécologie, Dijon) using partial least square path modelling (PLS-PM). Our results showed that farming practices had a positive direct effect on crop productivity (β = 0.32). Farming practices decreased weed pressure (β = -0.19) and had a sufficiently negative effect on weeds to counteract the negative impact of weeds on yield (β = -0.12). Thus, the indirect effect of farming practices on productivity through a change of weed pressure was positive and accounted for 7% of the total (direct + indirect) effect of farming practices on productivity. This key result confirms that effective weed management can sustain crop production.Les agriculteurs mettent en oeuvre un ensemble de pratiques de façon raisonnée dans le but d’optimiser/maximiser leur production tout en réduisant l’action des facteurs limitant biotiques (ex. adventices) et abiotiques (ex. nutriments) sur la culture. Notre étude a pour objectif de quantifier l’effet direct et indirect (via une action sur la flore adventice) des pratiques agricoles sur le rendement. Nous avons analysé les relations entre les pratiques agricoles, la flore et le rendement de 152 parcelles de blé d’hiver sur la zone d’étude de Fénay (UMR Agroécologie, Dijon) par PLS-PM (partial least square path modelling). Nos résultats montrent que les pratiques agricoles ont un effet direct positif (β = 0,32) sur le rendement et négatif (β = -0,19) sur la flore. Cet effet contrebalance l’effet négatif (β = -0,12) de la flore sur le rendement. Notre étude montre que les pratiques agricoles ont un effet indirect (via une modification de la flore) positif sur la production (7% de l’effet total). Ce résultat confirme que la gestion et la maîtrise de la flore adventice permet le maintien du potentiel de production agricole

Identification of the Proteins Determining the Blood Circulation Time of Nanoparticles

International audienceThe therapeutic efficacy and adverse impacts of nanoparticles (NPs) are strongly dependent on their systemic circulation time. The corona proteins adsorbed on the NPs determine their plasma half-lives, and hence, it is crucial to identify the proteins shortening or extending their circulation time. In this work, the in vivo circulation time and corona composition of superparamagnetic iron oxide nanoparticles (SPIONs) with different surface charges/chemistries were analyzed over time. SPIONs with neutral and positive charges showed the longest and shortest circulation times, respectively. The most striking observation was that corona-coated NPs with similar opsonin/dysopsonin content showed different circulation times, implying these biomolecules are not the only contributing factors. Long-circulating NPs adsorb higher concentrations of osteopontin, lipoprotein lipase, coagulation factor VII, matrix Gla protein, secreted phosphoprotein 24, alpha-2-HS-glycoprotein, and apolipoprotein C-I, while short-circulating NPs adsorb higher amounts of hemoglobin. Therefore, these proteins may be considered to be determining factors governing the NP systemic circulation tim

Procollagen C-Proteinase Enhancer 1 (PCPE-1) is a marker of myocardial fibrosis and impaired cardiac function in a murine model of pressure overload

Aims Procollagen C-proteinase enhancer 1 (PCPE-1) is an extracellular matrix protein and a major regulator of fibrillar collagen biosynthesis. Previous work has shown that its abundance is often increased in the context of tissue repair and fibrosis. The present study was designed to evaluate its potential as a biomarker of myocardial interstitial fibrosis (MIF), a well-established pathogenic pathway leading to heart failure. (2) Methods and Results Cardiac fibrosis was induced in rats using an optimized model of chronic pressure overload triggered by angiotensin II and N ω -nitro-L-arginine methyl ester (L-NAME). All treated animals suffered from heart hypertrophy and the increase in heart collagen volume fraction (CVF), evidenced by histology and 68 Ga-Collagelin uptake, confirmed the development of cardiac fibrosis. Functional analysis by simultaneous PET-MRI further showed that our model closely reflected the pathological features seen in human MIF, including left ventricle thickening and diastolic dysfunction associated with decreased ejection fraction. PCPE-1 mRNA and protein levels were augmented by factors of 3.4 and 6.1 respectively in the heart tissue of treated rats. Moreover, protein abundance was well-correlated with CVF (r=0.92, p<0.0001) and PCPE-1 immuno-detection mainly localized the protein to fibrotic areas. Finally, PCPE-1 plasma levels measured by ELISA were increased in fibrotic rats compared to controls. (3) Conclusion Together, our findings demonstrate that PCPE-1 levels in the heart and circulation tightly reflect the cardiac fibrosis status and heart function impairment in rats and suggest that it could be a very useful marker to monitor human heart diseases leading to fibrosis

Separating the confounding effects of farming practices on weeds and winter wheat production using path modelling

Optimal crop yield can be achieved directly by optimizing farming practices to increase crop growth and indirectly by optimizing pest management to decrease pest pressure. The aim of this study was to quantify the indirect effect of farming practices on yield through a change of the weed pressure and, thereby, disentangle the effect of farming practices on yield and weeds. Between 2006 and 2012 in Burgundy, France, 152 winter wheat fields were surveyed for weeds and farmers were interviewed about their farming practices and yields. Data were analysed using partial least square path modelling (PLS-PM). A path model that related farming intensity (fallow management, sowing, chemical pest control and fertilization), crop productivity (yield), and weed pressure was designed and validated. It was then used to assess the relationships between the identified variables (beta path coefficients) and compare groups of fields varying in, the preceding crop, herbicide use and weed pressure in the field. Farming intensity had a positive effect on crop productivity (beta = 0.32). Weed pressure negatively impacted crop productivity (beta = -0.12). Farming intensity decreased weed pressure and had a sufficiently negative effect on weeds (beta = -0.19) to counteract the negative impact of weeds on crop productivity. Therefore, the indirect effect of farming intensity on crop productivity through a change of weed pressure was positive and accounted for 7% of the total (direct + indirect) effect of farming intensity on crop productivity. The indirect effect of farming intensity on crop productivity varied by preceding crop (3.6% and 23% with a winter and spring/summer preceding crop, respectively) and herbicide use (14.1% and 2.1% when herbicide use was less and more than the regional reference, respectively) and weed pressure (0.5% and 2.6% when the total weed abundance after weeding was less and more than 2 individuals m(-2), respectively). From the path model, we quantified the direct and indirect effects of farming intensity on crop productivity to show that effective weed management can sustain crop production in cropping systems with reduced herbicide use

Response shift effects on measuring post-operative quality of life among breast cancer patients: a multicenter cohort study.

International audiencePURPOSE: To characterize response shift effects in patients with breast cancer (BC). METHODS: The QLQ-C30, BR23, and EurQOL-EQ-5D were assessed at baseline and at the end of the first hospitalization. We used the then-test approach to characterize changes in internal standards by calculating the mean difference between the then-test (retrospective measure) and pre-test baseline QoL assessments. The Ideal Scale Approach was also used to assess changes in standards by comparing health and QoL expectancies between baseline and the end of the first hospitalization. Successive Comparison Approach was used to assess changes in values through the longitudinal assessment of the relative importance of EuroQOL dimensions. RESULTS: The results of this study showed that recalibration RS effects occurred early after the first hospitalization for 6/15 dimensions of QLQ-C30 (emotional, cognitive, fatigue, insomnia, appetite loss, diarrhea) and 2/8 of BR-23 (future perspective, systemic therapy side effects). Moreover, health and QoL expectancies changed between the baseline and the end of the first hospitalization, and changes in values were seen for the self-care and usual activities dimensions of the EuroQOL-EQ-5D. CONCLUSIONS: The occurrence of RS early after the first hospitalization suggests that it needs to be taken into account to interpret QoL changes in BC

Impact of response shift on time to deterioration in quality of life scores in breast cancer patients.

BACKGROUND: This prospective multicenter study aimed to study the impact of the recalibration component of response-shift (RS) on time to deterioration (TTD) in health related quality of life (QoL) scores in breast cancer (BC) patients and the influence of baseline QoL expectations on TTD. METHODS: The EORTC-QLQ-C30 and BR-23 questionnaires were used to assess the QoL in a prospective multicenter study at inclusion (T0), at the end of the first hospitalization (T1) and, three (T2) and 6 months after the first hospitalization (T3). Recalibration was investigated by the then-test method. QoL expectancy was assessed at diagnosis. Deterioration was defined as a 5-point decrease in QoL scores, considered a minimal clinically important difference (MCID). TTD was estimated using the Kaplan-Meier method. Cox regression analyses were used to identify factors influencing TTD. RESULTS: From February 2006 to February 2008, 381 women were included. Recalibration of breast cancer patients' internal standards in the assessment of their QoL had an impact on TTD. Median TTD were significantly shorter when recalibration was not taken into account than when recalibration was taken into account for global health, role-functioning, social-functioning, body-image and side effects of systemic therapy. Cox multivariate analyses showed that for body image, when recalibration was taken into account, radiotherapy was associated with a shorter TTD (HR: 0.60[0.38-0.94], whereas, no significant impact of surgery type on TTD was observed. For global health, cognitive and social functioning dimensions, patients expecting a deterioration in their QoL at baseline had a significantly shorter TTD. CONCLUSIONS: Our results showed that RS and baseline QoL expectations were associated with time to deterioration in breast cancer patients