Biology subjects

Heins-Marroquin, U.

Publications and source records attributed to Heins-Marroquin, U..

3 recordsLinked to original sources

bioRxiv2026

Fasting reverses PLN R14del-mediated cardiomyopathy through lysosomal reactivation

Genetic cardiomyopathies consist of a heterogeneous group of myocardial disorders caused by variants that disrupt key regulators of cardiac structure and function. Variants in PLN, encoding phospholamban (PLN), the main inhibitor of the sarco/endoplasmic reticulum Ca{superscript 2}-ATPase 2a (SERCA2a), have been linked to both dilated cardiomyopathy (DCM) and arrhythmogenic cardiomyopathy (ACM). Among these, the PLN Arg14del (R14del) variant is the most prevalent. PLN R14del cardiomyopathy is characterized by the accumulation of large perinuclear PLN aggregates in cardiomyocytes of end-stage heart failure tissue. However, the mechanisms driving PLN aggregate formation and their role in disease progression remain unresolved. Using a humanized plna R14del zebrafish model, left ventricular tissue from end-stage PLN R14del cardiomyopathy patients and pharmacological modeling in wild type (WT) cardiac slices, we demonstrate that previously described PLN aggregates represent accumulated sarcoplasmic reticulum (SR)-derived PLN-containing vesicles that form due to impaired SERCA2a activity and increased cytosolic Ca{superscript 2} levels. Furthermore, these SR-derived vesicles often localize adjacent to lysosomes. Interestingly, Ca2+ dysregulation in plna R14del hearts leads to reduced lysosomal function, resulting in SR-derived vesicle accumulation at the microtubule organizing center (MTOC). This perinuclear accumulation induces microtubule aster formation and subsequent cellular disorganization, including sarcomere misalignment and nuclear deformation. Strikingly, reactivation of lysosomal function through fasting reduces SR-derived vesicle accumulation, restores microtubule integrity, and rescues cellular organization in plna R14del zebrafish hearts. Together, these findings identify impaired lysosomal clearance of SR-derived vesicles and the resulting microtubule disorganization as key pathological mechanisms driving PLN R14del cardiomyopathy. Additionally, our results highlight lysosomal reactivation as a promising potential therapeutic strategy to halt or reverse PLN R14del cardiomyopathy progression. Main findingsO_LIPLN aggregates in PLN R14del cardiomyopathy represent SR-derived vesicles formed due to Ca{superscript 2} dysregulation. C_LIO_LIThese SR-derived vesicles often localize perinuclearly at the microtubule organizing center (MTOC), where they are positioned adjacent to lysosomes. C_LIO_LICa2+ dysregulation leads to lysosomal dysfunction which drives vesicle accumulation responsible for microtubule remodeling and pathological cellular rearrangements. C_LIO_LILysosomal reactivation restores vesicle clearance and rescues cardiomyocyte structure. C_LI

cell biology↗

bioRxiv2023

CLN3 deficiency leads to neurological and metabolic perturbations during early development

Juvenile Neuronal Ceroid Lipofuscinosis (or Batten disease) is an autosomal recessive, rare neurodegenerative disorder that affects mainly children above the age of 5 years and is most commonly caused by mutations in the highly conserved CLN3 gene. Here, we generated cln3 morphants and stable mutant lines in zebrafish. Although neither morphant nor mutant cln3 larvae showed any obvious developmental or morphological defects, behavioral phenotyping of the mutant larvae revealed higher basal activity, hyposensitivity to abrupt light changes and hypersensitivity to pro-convulsive drugs. Importantly, in-depth metabolomics and lipidomics analyses revealed significant accumulation of several glycerophosphodiesters (GPDs) and a global decrease of bis(monoacylglycero)phosphate (BMP) species, two classes of molecules previously proposed as potential biomarkers for CLN3 disease based on independent studies in other organisms. We could also demonstrate GPD accumulation in human-induced pluripotent stem cell-derived cerebral organoids carrying a pathogenic variant for CLN3. Our models revealed that GPDs accumulate at very early stages of life in the absence of functional CLN3 and highlight glycerophosphoinositol and BMP as promising biomarker candidates for pre-symptomatic CLN3 disease.

molecular biology↗

bioRxiv2018

Deep learning image recognition enables efficient genome editing in zebrafish by automated injections

One of the most popular techniques in zebrafish research is microinjection, as it is a rapid and efficient way to genetically manipulate early developing embryos, and to introduce microbes or tracers at larval stages.\n\nHere we demonstrate the development of a machine learning software that allows for microinjection at a trained target site in zebrafish eggs at unprecedented speed. The software is based on the open-source deep-learning library Inception v3.\n\nIn a first step, the software distinguishes wells containing embryos at one-cell stage from wells to be skipped with an accuracy of 93%. A second step was developed to pinpoint the injection site. Deep learning allows to predict this location on average within 42 {micro}m to manually annotated sites. Using a Graphics Processing Unit (GPU), both steps together take less than 100 milliseconds. We first tested our system by injecting a morpholino into the middle of the yolk and found that the automated injection efficiency is as efficient as manual injection (~ 80%). Next, we tested both CRISPR/Cas9 and DNA construct injections into the zygote and obtained a comparable efficiency to that of an experienced experimentalist. Combined with a higher throughput, this results in a higher yield. Hence, the automated injection of CRISPR/Cas9 will allow high-throughput applications to knock out and knock in relevant genes to study their mechanisms or pathways of interest in diverse areas of biomedical research.

molecular biology↗