Biology subjects

Leon, E. C.

Publications and source records attributed to Leon, E. C..

3 recordsLinked to original sources

bioRxiv2025

Highly sensitive chemiluminescence imaging of misfolded proteins in neurodegenerative models

Visualizing misfolded proteins would greatly facilitate early diagnosis, etiology elucidation, and therapy monitoring of neurodegeneration. Although several probes have been reported, simple and versatile detection in vivo is still challenging. We demonstrated that both generic and precise detection of misfolded proteins could be achieved with a chemiluminescence probe, ADLumin-1. For the generic aspect, ADLumin-1 was highly sensitive to various misfolded proteins, showing up to 127.73-fold higher signal-to-noise ratio than Thioflavin T. ADLumin-1 could also non-invasively visualize misfolded proteins in mouse models of Parkinsons disease, Alzheimers disease and amyotrophic lateral sclerosis. Furthermore, ADLumin-1 displayed precise detection value for -synuclein by combining with PMCA in vitro and bioorthogonal ChRET imaging technology in vivo. ADLumin-1 can selectively detect -synuclein in CSF at the femtomolar level and enables in situ monitoring of misfolded -synuclein in vivo. Combining generality and precision, our findings could be widely applied in preclinical and clinical studies of neurodegenerative diseases. TeaserA highly sensitive chemiluminescence probe enables both generic and precise detection of various misfolded proteins

biochemistry↗

bioRxiv2024

Gene Therapy Mediates Therapeutic Improvement in Cardiac Hypertrophy and Survival in a Murine Model of MYBPC3-Associated Cardiomyopathy

BackgroundHypertrophic cardiomyopathy (HCM) affects an estimated 600,000 people in the U.S. and is the leading cause of sudden cardiac arrest in those under 18. Loss-of-function mutations in Myosin Binding Protein C3, MYBPC3, are the most common genetic cause of HCM. The majority of MYBPC3 mutations causative for HCM result in truncations. The sarcomeric pathophysiology of the majority of HCM patients with MYBPC3 mutations appears to be due to haploinsufficiency, as the total amount of MYBPC3 protein incorporated into sarcomeres falls significantly below normal. MethodsA clear path for the treatment of haploinsufficiency is the restoration of the insufficient gene product; in this case wild-type MYBPC3. To achieve this, we engineered an AAV vector (TN-201) with superior properties for mediating cardiomyocyte-selective expression of MYBPC3 after systemic delivery. ResultsWe have demonstrated for the first time with AAV gene therapy the ability of both a mouse surrogate and TN-201, which encodes human MYBPC3 to reverse cardiac hypertrophy and systolic dysfunction and to improve diastolic dysfunction and survival in a symptomatic MYBPC3-deficient murine model of disease. Dose-ranging efficacy studies exhibited restoration of wild-type MYBPC3 protein levels and saturation of cardiac improvement at the clinically relevant dose of 3E13 vg/kg, outperforming a previously published construct. Further, we have established stable cardiac benefit for greater than one year post-injection, as well as reversal of cardiac dysfunction even in late-stage models of disease. ConclusionsOur data suggest that by restoring MYBPC3 to the sarcomere, TN-201 has the potential to slow and even reverse the course of the disease in patients with MYBPC3-associated HCM.

genetics↗

bioRxiv2021

Radiosynthesis and preclinical evaluation of a carbon-11 labeled PDE7 inhibitor for PET neuroimaging

BackgroundDysfunction of cyclic nucleotide phosphodiesterase 7 (PDE7) has been associated with excess intracellular cAMP concentrations, fueling pathogenic processes that are implicated in neurodegenerative disorders. The aim of this study was to develop a suitable PDE7-targeted positron emission tomography (PET) probe that allows non-invasive mapping of PDE7 in the mammalian brain. MethodsBased on a spiro cyclohexane-1,4-quinazolinone scaffold with known inhibitory properties towards PDE7, we designed and synthesized a methoxy analog that was suitable for carbon-11 labeling. Radiosynthesis was conducted with the respective desmethyl precursor using [11C]MeI. The resulting PET probe, codenamed [11C]26, was evaluated by cell uptake studies, ex vivo biodistribution and radiometabolite studies, as well as in vivo PET experiments in rodents and nonhuman primates (NHP). ResultsTarget compound 26 and the corresponding phenolic precursor were synthesized in 2-3 steps with overall yields of 49.5% and 12.4%, respectively. An inhibitory constant (IC50) of 31 nM towards PDE7 was obtained and no significant interaction with other PDE isoforms were observed. [11C]26 was synthesized in high molar activities (170 - 220 GBq/{micro}mol) with radiochemical yields of 34{+/-}7%. In vitro cell uptake of [11C]26 was 6-7 folds higher in PDE7 overexpressing cells, as compared to the controls, whereas an in vitro specificity of up to 90% was measured. Ex vivo metabolite studies revealed a high fraction of intact parent in the rat brain (98% at 5 min and 75% at 30 min post injection). Considerable brain penetration was further corroborated by ex vivo biodistribution and PET imaging studies - the latter showing heterogenic brain uptake. While marginal specific binding was observed by PET studies in rodents, a moderate, but dose-dependent, blockade was observed in the NHP brain following pretreatment with non-radioactive 26. ConclusionIn this work, we report on the preclinical evaluation of [11C]26 (codename [11C]P7-2104), a PDE7-targeted PET ligand that is based on a spiroquinazolinone scaffold. [11C]26 displayed promising in vitro performance characteristics, a moderate degree of specific binding in PET studies with NHP. Accordingly, [11C]26 will serve as a valuable lead compound for the development of a new arsenal of PDE7-targeted probes with potentially improved in vivo specificity.

neuroscience↗