Search bioRxiv⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/2025.09.23.677965

Hepatic gene replacement restores energy metabolism and doubles the survival in mouse model of GRACILE syndrome, a neonatal mitochondrial disease

Banerjee, R.·Purhonen, J.·Sultana, N.·Kietz, C.·Fellman, V.·Kallijarvi, J.
View original source ↗Export metadata ↓

Abstract

Preclinical gene therapy studies of mitochondrial diseases remain limited due to their multisystemic manifestations and the scarcity of physiologically relevant animal models. Mutations in BCS1L, a nuclear gene encoding an assembly factor for mitochondrial complex III (CIII), are the most common cause of pediatric CIII deficiency. The most severe phenotype, GRACILE syndrome, is caused by a homozygous Finnish founder mutation (c.A232G, p.S78G). The corresponding Bcs1lp.S78G knock-in mouse model effectively recapitulates the human disease, with juvenile-onset hepatopathy, tubulopathy, growth restriction, segmental progeria, and short survival. Here, we performed recombinant adeno-associated virus (rAAV)-mediated gene replacement in this model, which features a postnatal presymptomatic window until weaning. A single intraperitoneal injection of rAAV encoding wild-type Bcs1l restored CIII assembly and activity in the liver, preventing hepatopathy. Hepatocyte-specific correction was sufficient to ameliorate hypoglycemia, improve growth, normalize systemic metabolism, and extend survival by nearly two-fold, despite persistent CIII deficiency in other tissues. Remarkably, liver-directed rescue also prevented skeletal muscle transcriptomic changes, particularly those linked to altered energy substrate utilization. These results underscore the central role of the liver in systemic energy homeostasis and growth regulation in multiorgan mitochondrial diseases and demonstrate the therapeutic potential of hepatocyte-directed gene replacement in phenotypes with prominent hepatopathy. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=127 SRC="FIGDIR/small/677965v1_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@b1cf50org.highwire.dtl.DTLVardef@1a1c2e2org.highwire.dtl.DTLVardef@101bdb6org.highwire.dtl.DTLVardef@14e11e3_HPS_FORMAT_FIGEXP M_FIG Graphical abstract C_FIG

Source connections

Explore related subjects

physiologyPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Banerjee, R., Purhonen, J., Sultana, N., Kietz, C., Fellman, V., Kallijarvi, J.. 2025-09-25. Hepatic gene replacement restores energy metabolism and doubles the survival in mouse model of GRACILE syndrome, a neonatal mitochondrial disease. https://doi.org/10.1101/2025.09.23.677965

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Hypothalamic Farnesoid X Receptor deficiency alters energy balance by modulating hepatic glucose production and adipose tissue metabolism through central insulin signaling.

Objectives: The bile acid nuclear receptor Farnesoid X Receptor (FXR, NR1H4) is a major regulator of metabolism and energy homeostasis in peripheral organs. It modulates bile acid, glucose, and lipid metabolism, as well as fat mass and body weight. However, FXR is also expressed in the brain, particularly in the hypothalamus, a key center for the regulation of energy homeostasis. Although one study has demonstrated a role for brain FXR activation in energy balance, its specific hypothalamic role is still unknown. Here, we examined the role of FXR in the mediobasal hypothalamus in the regulation of energy balance. Methods: We used a genetic approach combined with metabolic phenotyping to determine the effect of FXR invalidation in the mediobasal hypothalamus on metabolic parameters involved in the central regulation of energy homeostasis. Results: Our results demonstrate that hypothalamic FXR deficiency induces a positive energy balance, resulting in a reduction in energy expenditure due to alterations in glucose metabolism accompanied by structural changes in white adipose tissues. Conclusion: This study uncovers a previously unrecognized role for hypothalamic FXR in the central homeostatic control of energy balance, providing new insights into its contribution to peripheral glucose metabolism and adipose tissue structural remodeling.

physiology↗
bioRxiv2026

Rad and Phospholamban are Key Drivers of the Ventricular Adrenergic Response and Stress-Induced Arrhythmia

The adrenergic response is a fundamental mechanism that regulates heart rate (chronotropy), cardiac contractility (inotropy) and relaxation (lusitropy). Adrenergic stress is also a recognized trigger of arrhythmia in disease. Yet, our understanding of the underlying molecular basis remains incomplete. Protein kinase A (PKA) and the calcium/calmodulin-dependent kinase II (CaMKII) phosphorylate multiple targets proposed to participate in the adrenergic response, including the GTP-binding protein Rad, phospholamban (PLB) and ryanodine receptor 2 (RyR2). Here we demonstrate that phosphorylation of both Rad and PLB is necessary for inotropy and lusitropy. We show that changes in cardiac contractility and relaxation are primarily dependent on intracellular calcium handling. Finally, we report that Rad and PLB control stress-induced arrhythmogenesis, despite the phosphorylation of other pro-arrhythmic targets. We have identified the essential molecular components of the adrenergic response, resolving a long-standing debate in cardiac excitation-contraction coupling and refining current models of sympathetic regulation in health and disease.

physiology↗
bioRxiv2026

Light-cycle time-restricted feeding remodels a hidden layer of the cardiac transcriptome through sex-specific transcript switching

Light-cycle time-restricted feeding disrupts daily cardiovascular and thermoregulatory rhythms, but the molecular effects of light-cycle time-restricted feeding on the heart have been measured only at the level of total gene expression. We used Oxford Nanopore long-read RNA sequencing to resolve the full-length ventricular transcriptome from male and female mice under ad libitum feeding or light-cycle time-restricted feeding across the 24-hour cycle. Greater than 20% of cardiac transcripts represent unannotated variants of known genes absent from the current GENCODE reference annotation. Light-cycle time-restricted feeding reorganizes transcript usage across hundreds of genes, including genes encoding splicing regulators, largely without changing total gene expression. The genes affected are sex-specific, with fewer than 2% of changes shared at the gene, transcript, and transcript-usage levels. We show that transcript-level regulation is a previously underrecognized component of the cardiac response to altered feeding behavior, undetected by conventional short-read approaches.

physiology↗