Biology subjects

Mcilroy, G. D.

Publications and source records attributed to Mcilroy, G. D..

3 recordsLinked to original sources

bioRxiv2024

Preclinical evaluation of tissue-selective gene therapies for congenital generalised lipodystrophy

Lipodystrophy is a rare disorder which can be life-threatening. Here individuals fail to develop or maintain appropriate adipose tissue stores. This typically causes severe metabolic complications, including hepatic steatosis and lipoatrophic diabetes. There is no cure for lipodystrophy, and treatment options remain very limited. Here we evaluate whether tissue-selective adeno-associated virus (AAV) vectors can provide a targeted form of gene therapy for lipodystrophy, using a preclinical lipodystrophic mouse model of Bscl2 deficiency. We designed AAV vectors containing the mini/aP2 or thyroxine-binding globulin promoter to selectively target adipose or liver respectively. The AAV-aP2 vectors also contained the liver-specific microRNA-122 target sequence, restricting hepatic transgene expression. Systemic delivery of AAV-aP2 vectors overexpressing human BSCL2 restored adipose tissue development and metabolic health in lipodystrophic mice without detectable expression in the liver. High doses (1x1012 GCs) of liver-selective vectors led to off target expression and adipose tissue development, whilst low doses (1x1010 GCs) expressed selectively and robustly in the liver but did not improve metabolic health. This reveals that adipose tissue-selective, but not liver directed, AAV-mediated gene therapy is sufficient to substantially recover metabolic health in generalised lipodystrophy. This provides an exciting potential new avenue for an effective, targeted, and thereby safer therapeutic intervention.

molecular biology↗

bioRxiv2024

Hydroxysteroid 17-beta dehydrogenase 13 (Hsd17b13) knockdown attenuates liver steatosis in high-fat diet obese mice

Hydroxysteroid 17-beta dehydrogenase 13 (HSD17B13) loss-of-function gene variants are associated with decreased risk of metabolic dysfunction-associated steatotic liver disease (MASLD). Our RNA-seq analysis of steatotic liver from obese mice -/+ Fenretinide treatment identified major beneficial effects of Fenretinide on hepatic gene expression including Hsd17b13. We sought to determine the relationship between Hsd17b13 expression and MASLD and to validate it as a therapeutic target by liver-specific knockdown. Hsd17b13 expression, which is unique to hepatocytes and associated with the lipid-droplet, was elevated in multiple models of MASLD and normalised with prevention of obesity and steatotic liver. Direct, liver- specific, shRNA-mediated knockdown of Hsd17b13 (shHsd17b13) in high-fat diet (HFD)-obese mice, markedly improved hepatic steatosis with no effect on body weight, adiposity or glycaemia. shHsd17b13 decreased elevated serum ALT, serum FGF21 levels and markers of liver fibrosis e.g. Timp2. shHsd17b13 knockdown in HFD-obese mice and Hsd17b13 overexpression in cells reciprocally regulated expression of lipid metabolism genes e.g. Cd36. Global lipidomic analysis of liver tissue revealed a major decrease in diacylglycerols (e.g. DAG 34:3) with shHsd17b13 and an increase in phosphatidylcholines containing polyunsaturated fatty acids (PUFA) e.g. PC 34:3 and PC 42:10. Expression of key genes involved in phospholipid and PUFA metabolism e.g. Cept1, were also reciprocally regulated suggesting a potential mechanism of Hsd17b13 biological function and role in MASLD. In conclusion, Hsd17b13 knockdown in HFD-obese adult mice was able to alleviate MASLD via regulation of fatty acid and phospholipid metabolism, thereby confirming HSD17B13 as a genuine therapeutic target for MASLD and development of liver fibrosis. KEY POINTSO_LIHSD17B13 loss-of-function gene variants are associated with decreased risk of metabolic dysfunction-associated (MA) steatotic liver disease and steatohepatitis (MASLD and MASH). C_LIO_LIRNA-seq analysis of steatotic liver identified beneficial effects of Fenretinide on hepatic gene expression including downregulation of Hsd17b13. C_LIO_LILiver-specific shRNA knockdown of Hsd17b13 in obese mice markedly improved hepatic steatosis and markers of liver health e.g. serum ALT, serum Fgf21 levels. C_LIO_LIHsd17b13 influenced expression of lipid/phospholipid metabolism genes e.g. Cd36 and Cept1 and phosphatidylcholines PC 34:3 and PC 42:10. C_LIO_LIOur study suggests a mechanism of HSD17B13s biological function and the strong rationale behind targeting HSD17B13 for MASLD/MASH. C_LI

physiology↗

bioRxiv2023

GLP-1 Receptor Agonist Improves Metabolic Disease in a Pre-clinical Model of Lipodystrophy

Individuals with lipodystrophies typically suffer from significant metabolic disease linked to adipose tissue dysfunction including severe insulin resistance and lipoatrophic diabetes, hepatic steatosis and hyperphagia. Current treatment options are limited and beter therapies for affected individuals are urgently needed. No systematic, detailed analyses exist of the effects of glucagon like peptide-1 receptor (GLP-1R) agonists in the treatment of lipoatrophic diabetes. Here we examined the effects of the GLP-1R agonist liraglutide in seipin knockout mice, a pre-clinical model of generalised lipodystrophy. Acute liraglutide treatment of seipin knockout mice significantly improved insulin, glucose and pyruvate tolerance. Once-daily injection of seipin knockout mice with liraglutide for 14 days led to a modest reduction in food intake but significant improvements in hepatomegaly associated with steatosis and significantly reduced markers of liver fibrosis. Detailed examination of the pancreas revealed that liraglutide enhanced insulin secretion in response to glucose challenge with concomitantly improved glucose control. Thus, GLP-1R agonist liraglutide significantly improved multiple aspects of lipoatrophic diabetes and hepatic steatosis in mice with congenital generalised lipodystrophy. This provides important insights regarding the benefits of GLP-1R agonists for treating lipodystrophy, informing more widespread use to improve the health of individuals with this condition.

pharmacology and toxicology↗