CD73 deficiency does not aggravate angiotensin II-induced aortic inflammation in mice

Abstract Vascular inflammation plays a key role in the development of aortic diseases. A potential novel target for treatment might be CD73, an ecto-5′-nucleotidase that generates anti-inflammatory adenosine in the extracellular space. Here, we investigated whether a lack of CD73 results in enhanced aortic inflammation. To this end, angiotensin II was infused into wildtype and CD73−/− mice over 10 days. Before and after infusion, mice were analyzed using magnetic resonance imaging, ultrasound, flow cytometry, and histology. The impact of age and gender was investigated using female and male mice of three and six months of age, respectively. Angiotensin II infusion led to increased immune cell infiltration in both genotypes’ aortae, but depletion of CD73 had no impact on immune cell recruitment. These findings were not modified by age or sex. No substantial difference in morphological or functional characteristics could be detected between wildtype and CD73−/− mice. Interestingly, the expression of CD73 on neutrophils decreased significantly in wildtype mice during treatment. In summary, we have found no evidence that CD73 deficiency affects the onset of aortic inflammation. However, as CD73 expression decreased during disease induction, an increase in CD73 by pharmaceutical intervention might result in lower vascular inflammation and less vascular disease

Biodegradable Polyphosphoester Micelles Act as Both Background-free 31P Magnetic Resonance Imaging Agents and Drug Nanocarriers

Imaging and tracing materials inside the body is essential to develop functional materials for personalized therapies, including drug delivering nanocarriers and artificial tissues. Magnetic Resonance Imaging (MRI) is a key whole-body imaging technology, where heteronuclear MRI agents enable background-free, quantitative labeling. However, many MRI agents raised concerns due to environmental pollution and organ accumulation. As a solution, we developed a biodegradable, biocompatible polymer platform for heteronuclear 31P magnetic resonance imaging (MRI). We introduce polyphosphoester colloids for heteronuclear MRI using 31P-nucleus. 31P MRI has been severely hampered by unfavorable magnetic resonance properties of 31P, including intrinsic background and low sensitivity. We overcame these fundamental challenges in imaging of 31P by tailoring molecular and structural features of polymeric colloids. We have synthesized gradient-type polyphosphonate copolymers that self-assemble into well-defined micelles. The gradient leads to favorable MRI characteristics compared with homo- and block copolymers. Background-free imaging and biodegradation were proven in vivo in Manduca sexta. Furthermore, we demonstrate by encapsulation of the potent drug PROTAC ARV-825 that these amphiphilic copolymers can simultaneously deliver hydrophobic drugs and thus enable theranostics. We present a unique platform of biocompatible, degradable polyphosphoesters that inherently act as background-free MRI agents and delivery vehicles

Biodegradable polyphosphoester micelles act as both background-free 31P magnetic resonance imaging agents and drug nanocarriers

Abstract In vivo monitoring of polymers is crucial for drug delivery and tissue regeneration. Magnetic resonance imaging (MRI) is a whole-body imaging technique, and heteronuclear MRI allows quantitative imaging. However, MRI agents can result in environmental pollution and organ accumulation. To address this, we introduce biocompatible and biodegradable polyphosphoesters, as MRI-traceable polymers using the 31P centers in the polymer backbone. We overcome challenges in 31P MRI, including background interference and low sensitivity, by modifying the molecular environment of 31P, assembling polymers into colloids, and tailoring the polymers’ microstructure to adjust MRI-relaxation times. Specifically, gradient-type polyphosphonate-copolymers demonstrate improved MRI-relaxation times compared to homo- and block copolymers, making them suitable for imaging. We validate background-free imaging and biodegradation in vivo using Manduca sexta. Furthermore, encapsulating the potent drug PROTAC allows using these amphiphilic copolymers to simultaneously deliver drugs, enabling theranostics. This first report paves the way for polyphosphoesters as background-free MRI-traceable polymers for theranostic applications