Malte Juchem

The lysosomal storage disorder Fabry disease results from α‐galactosidase A deficiency, leading to excessive glycosphingolipid substrate accumulation, primarily globotriaosylceramide (Gb3). While the underlying molecular mechanisms remain elusive, multi‐systemic complications ultimately culminate in premature death, with heart failure being the leading cause of death. Current treatment options fail to treat Fabry disease adequately and only delay its progression. Preclinical studies on an alternative approach, systemic delivery of nucleoside‐modified GLA mRNA (modGLA), suggest improved effectiveness over existing therapies in reducing glycosphingolipid levels in the heart. It remains unclear whether modGLA can rescue Fabry cardiomyopathy phenotypes at the cellular level, which are not faithfully recapitulated in current animal models. To address this, we investigated characteristic phenotypes in two new models of Fabry cardiomyopathy utilizing human iPSC‐derived cardiomyocytes in transcriptomic and functional analyses. These human Fabry disease cardiomyocytes displayed broad transcriptional dysregulation, apoptosis, mitochondrial dysfunction, impaired reactive oxygen species handling, altered contractility, and enhanced calcium transient decay parameters. Mechanistically, phospholamban hyperphosphorylation may contribute to this calcium dysregulation. Consistently, modGLA therapy restored α‐galactosidase A activity, reduced glycosphingolipid deposition, and normalized molecular alterations, including phospholamban hyperphosphorylation and calcium decay parameters, supporting modGLA as a promising therapeutic strategy for Fabry disease.

The lysosomal storage disorder Fabry disease results from α-galactosidase A deficiency, leading to excessive glycosphingolipid substrate accumulation, primarily globotriaosylceramide (Gb3). While the underlying molecular mechanisms remain elusive, multi-systemic complications ultimately culminate in premature death, with heart failure being the leading cause of death. Current treatment options fail to treat Fabry disease adequately and only delay its progression. Preclinical studies on an alternative approach, systemic delivery of nucleoside-modified GLA mRNA (modGLA), suggest improved effectiveness over existing therapies in reducing glycosphingolipid levels in the heart. It remains unclear whether modGLA can rescue Fabry cardiomyopathy phenotypes at the cellular level, which are not faithfully recapitulated in current animal models. To address this, we investigated characteristic phenotypes in two new models of Fabry cardiomyopathy utilizing human iPSC-derived cardiomyocytes in transcriptomic and functional analyses. These human Fabry disease cardiomyocytes displayed broad transcriptional dysregulation, apoptosis, mitochondrial dysfunction, impaired reactive oxygen species handling, as well as enhanced decay parameters of calcium transients. Mechanistically, we identified hyperphosphorylated phospholamban as a major player in this calcium dysregulation. Strikingly, modGLA therapy of Fabry cardiomyocytes restored α-galactosidase A enzyme activity, reduced glycosphingolipid deposition, and normalized the observed molecular alterations, supporting modGLA therapy as a promising strategy for the treatment of Fabry disease.

Pulmonary Fibrosis (PF) is a life‐threatening illness that is characterized by progressive scarring in the lung interstitium. There is an urgent need for new PF therapies because current treatments only slow down the progression of fibrosis, and the median life expectancy post‐diagnosis is only 4–6 years. Since PF patients frequently exhibit telomere attrition, overexpressing telomerase, the enzyme responsible for synthesizing telomeres, represents a compelling therapeutic option. In this study, we in vitro transcribed human telomerase reverse transcriptase (hTERT) mRNA using modified nucleosides (modRNA). ModRNA hTERT treatment led to transient activation of telomerase activity in a dose‐dependent manner in MRC‐5 cells and, importantly, in primary human alveolar type II pneumocytes. Consequently, the proliferative capacity was increased, concomitant with reduced DNA damage and elongated telomere length. Notably, the induction of cellular immune response was only detectable at the highest modRNA concentration and returned to normal levels within 48 h. Next, we demonstrated that circularized, exonuclease‐resistant modRNA hTERT extended the transient expression profile, which may be clinically advantageous. Finally, we provided therapeutic proof of concept in organotypic 3D ex vivo human precision‐cut lung slices derived from end‐stage PF patients. Intriguingly, a single modRNA hTERT treatment inhibited senescence, as indicated by significantly lower levels of senescence‐associated β‐galactosidase. Pro‐inflammatory markers (IL6 and IL8) and, concurrently, the key fibrosis mediators TGFβ and COL1A1 were markedly reduced after modRNA and circular RNA hTERT treatment. In conclusion, the data presented herein provide initial evidence for the potential of RNA‐based hTERT therapy for treating human lung fibrosis.

Pulmonary Fibrosis (PF) is a life-threatening illness that is characterized by progressive scarring in the lung interstitium. There is an urgent need for new PF therapies because current treatments only slow down the progression of fibrosis and the median life expectancy post-diagnosis is only 4 to 6 years. Since PF patients frequently exhibit telomere attrition, overexpressing telomerase, the enzyme responsible for synthesizing telomeres represents a compelling therapeutic option. In this study, we in vitro transcribed human telomerase reverse transcriptase (hTERT) mRNA using modified nucleosides (modRNA). ModRNA hTERT treatment led to transient activation of telomerase activity in a dose-dependent manner in MRC-5 cells and, importantly, in primary human alveolar type II pneumocytes (ATII cells). Consequently, the proliferative capacity was increased, concomitant with reduced DNA damage and elongated telomere length. Notably, induction of cellular immune response was only detectable at the highest modRNA concentration, and returned to normal levels within 48 hours. Next, we demonstrated that circularized, exonuclease-resistant modRNA hTERT extended the transient expression profile which may be clinically advantageous. Finally, we provided therapeutic proof of concept in organotypic 3D ex vivo human precision-cut lung slices derived from end-stage PF patients. Intriguingly, a single modRNA hTERT treatment inhibited senescence as indicated by significantly lower levels of senescence-associated β-galactosidase, and pro-inflammatory IL6 and IL8. Concurrently, the key fibrosis mediators TGFβ and COL1A1 were markedly reduced. In conclusion, the data presented herein provide initial evidence for the potential of RNA-based hTERT therapy for treating human lung fibrosis.