Effects of gene therapy on cardiovascular symptoms of lysosomal storage diseases

Disturbances in mitochondrial quality control and mitochondria-lysosome contact underlie the cerebral cortex and heart damage of mucopolysaccharidosis type II mice

Mucopolysaccharidosis type II (or Hunter syndrome) is a lysosomal disease caused by mutations in the IDS gene, which encodes the enzyme iduronate 2-sulfatase. MPS II patients present with systemic clinical manifestations and, in the most severe cases, with severe central nervous system abnormalities. Cardiac alterations are also commonly observed. In this study, we evaluated the communication between mitochondria and lysosomes, as well as mitochondrial dynamics and bioenergetics, mitophagy/autophagy, and redox homeostasis in the cerebral cortex and heart of 6-month-old MPS II mice. Our findings showed a reduction in the content of protein TBC1D15 in the cerebral cortex and heart of MPS II mice and an increase in Rab7 in the heart of these animals, suggesting disturbances in the communication between mitochondria and lysosomes. Furthermore, decreased Drp1 levels, indicative of reduced fission, and increased VDAC1 and COX IV, suggesting an increase in mitochondrial mass, were seen in both tissues. Tom20 was also augmented in the cortex. Changes in parkin levels were also verified, indicating disrupted mitophagy. In the field of bioenergetics, we observed reduced activities of citrate synthase and malate dehydrogenase in the cortex, as well as decreased activities of isocitrate dehydrogenase, creatine kinase, and pyruvate kinase, along with diminished mitochondrial respiration in the cardiac tissue of deficient mice. However, a mild increase in lipid peroxidation was seen only in the heart. Our findings suggest that mitochondria-lysosome crosstalk disruption and bioenergetic failure contribute to the pathophysiology of brain and heart alterations in MPS II.

Cardiovascular Involvement in Fabry's Disease: New Advances in Diagnostic Strategies, Outcome Prediction and Management

Cardiovascular involvement is common in Fabry's disease and is the leading cause of morbidity and mortality. The research is focused on identifying diagnostic clues suggestive of cardiovascular involvement in the preclinical stage of the disease through clinical and imaging markers. Different pathophysiologically driven therapies are currently or will soon be available for the treatment of Fabry's disease, with the most significant benefit observed in the early stages of the disease. Thus, early diagnosis and risk stratification for adverse outcomes are crucial to determine when to start an aetiological treatment. This review describes the cardiovascular involvement in Fabry's disease, focusing on the advances in diagnostic strategies, outcome prediction and disease management.

Genome editing in lysosomal disorders

Lysosomal disorders are a group of heterogenous diseases caused by mutations in genes that encode for lysosomal proteins. With exception of some cases, these disorders still lack both knowledge of disease pathogenesis and specific therapies. In this sense, genome editing arises as a technique that allows both the creation of specific cell lines, animal models and gene therapy protocols for these disorders. Here we explain the main applications of genome editing for lysosomal diseases, with examples based on the literature. The ability to rewrite the genome will be of extreme importance to study and potentially treat these rare disorders.

Preparation and Biological Property Evaluation of Novel Cationic Lipid-Based Liposomes for Efficient Gene Delivery

Novel cationic lipid-based liposomes prepared using an amphiphilic cationic lipid material, N,N-dimethyl-(N',N'-di-stearoyl-1-ethyl)1,3-diaminopropane (DMSP), have been proposed to enhance the transfection of nucleic acids. Herein, we designed and investigated liposomes prepared using DMSP, soybean phosphatidylcholine, and cholesterol. This novel gene vector has high gene loading capabilities and excellent protection against nuclease degradation. An in vitro study showed that the liposomes had lower toxicity and superior cellular uptake and transfection efficiency compared with Lipofectamine 2000. An endosomal escape study revealed that the liposomes demonstrated high endosomal escape and released their genetic payload in the cytoplasm efficiently. Mechanistic studies indicated that the liposome/nucleic acid complexes entered cells through energy-dependent endocytosis that was mediated by fossa proteins. These results suggest that such cationic lipid-based liposome vectors have potential for clinical gene delivery.

Neonatal nonviral gene editing with the CRISPR/Cas9 system improves some cardiovascular, respiratory, and bone disease features of the mucopolysaccharidosis I phenotype in mice

Mucopolysaccharidosis type I (MPS I) is caused by deficiency of alpha-L-iduronidase (IDUA), leading to multisystemic accumulation of glycosaminoglycans (GAG). Untreated MPS I patients may die in the first decades of life, mostly due to cardiovascular and respiratory complications. We previously reported that the treatment of newborn MPS I mice with intravenous administration of lipossomal CRISPR/Cas9 complexes carrying the murine Idua gene aiming at the ROSA26 locus resulted in long-lasting IDUA activity and GAG reduction in various tissues. Following this, the present study reports the effects of gene editing in cardiovascular, respiratory, bone, and neurologic functions in MPS I mice. Bone morphology, specifically the width of zygomatic and femoral bones, showed partial improvement. Although heart valves were still thickened, cardiac mass and aortic elastin breaks were reduced, with normalization of aortic diameter. Pulmonary resistance was normalized, suggesting improvement in respiratory function. In contrast, behavioral abnormalities and neuroinflammation still persisted, suggesting deterioration of the neurological functions. The set of results shows that gene editing performed in newborn animals improved some manifestations of the MPS I disorder in bone, respiratory, and cardiovascular systems. However, further studies will be imperative to find better delivery strategies to reach "hard-to-treat" tissues to ensure better systemic and neurological effects.