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Biology subjects

Kwon, D.-H.

Publications and source records attributed to Kwon, D.-H..

4 recordsLinked to original sources

Mutation-Agnostic Base Editing of the Progerin Farnesylation Site Rescues Hutchinson-Gilford Progeria Syndrome Phenotypes in Neuromuscular Organoids

Hutchinson Gilford progeria syndrome (HGPS) is a fatal premature aging disorder caused by pathogenic farnesylated lamin A variants that disrupt nuclear architecture and DNA repair. Current therapies, including farnesyltransferase inhibitors, provide only modest survival benefits and lack molecular specificity, while mutation-specific genome-editing strategies cannot address atypical laminopathies. Here, we develop Farnesylation Amino acid Targeted Editing (FATE), a mutation-agnostic base-editing platform that selectively disrupts the LMNA farnesylation motif without affecting other farnesylated proteins. Using isogenic human pluripotent stem cell derived neuromuscular organoids (NMOs), we reveal muscle-specific progerin accumulation that sequesters 53BP1 and abolishes DNA damage foci formation. FATE eliminates perinuclear progerin, restores 53BP1 mobility, reconstitutes DNA repair foci, and normalizes heterochromatin architecture. Importantly, transient delivery of FATE mRNA conjugated with lipid nanoparticles to HGPS NMOs achieves efficient base editing and phenotypic rescue. These findings establish FATE as a mutation-independent therapeutic strategy targeting a fundamental pathogenic mechanism in HGPS and provide a proof-of-concept for RNA-based in situ genome editing in progeroid disease.

pathology↗

Shift from visceral to subcutaneous fat in Cyp17a1 knockout rats prevent the progression of metabolic syndrome

In this study, we investigated the effects of Cyp17a1 gene knockout (KO) on obesity and metabolic syndrome. Cyp17a1 KO in rats using CRISPR-Cas9 resulted in sex dimorphism and obesity, and interestingly, idiopathic accumulation was found in subcutaneous adipose tissue. Surprisingly, an insulin tolerance test and oral glucose tolerance test did not show any issues with insulin sensitivity and secretion despite hyperglycemia. In addition, Cyp17a1 KO rats showed normal plasma insulin and free fatty acid levels compared to wild-type rats, and blood biochemistry analysis revealed normal triglyceride, total cholesterol, high-density lipoprotein, and low-density lipoprotein levels. Cyp17a1 KO adipose-tissue-derived stem cells from subcutaneous fat showed increased expression of KLF5, an early adipogenesis marker, which implies enhanced adipogenic potential in subcutaneous adipose tissue. When gene expression associated with lipid, glucose, and insulin metabolism as well as inflammation in adipose tissue was examined, a metabolic shift to subcutaneous adipose tissue was discovered in the Cyp17a1 KO group. In conclusion, in the Cyp17a1 KO rat models we generated for the first time, the phenotype promoted by obesity reflected health obesity hypothesis, but this did not result in metabolic syndrome due to enhanced metabolism in the subcutaneous fats.

physiology↗

Topographic connectivity and cellular profiling reveal detailed input pathways and functionally distinct cell types in the subthalamic nucleus

The subthalamic nucleus (STN) controls psychomotor activity and is an efficient therapeutic deep brain stimulation target in Parkinsons disease patients. Despite evidence indicating position-dependent therapeutic effects and distinct functions within the STN, input circuit and cellular profile in the STN remain largely unclear. Using advanced neuroanatomical techniques, we constructed a comprehensive connectivity map of the indirect and hyperdirect pathways in both the mouse and human STN. Our detailed circuit- and cellular-level connectivity revealed a topographically graded organization with three convergent types of indirect and hyperdirect-pathways. Furthermore, we identified two functional types of glutamatergic STN neurons (parvalbumin, PV +/- neurons) segregated with a topographical distribution. Glutamatergic PV+ STN neurons contribute to burst firing. We confirmed synaptic connectivity from indirect and hyperdirect pathways to both PV+ and PV-. These data suggest a complex interplay of information integration within the basal ganglia underlying coordinated movement control and therapeutic effects.

neuroscience↗

SRF is a non-histone methylation target of KDM2B and SET7 in the regulation of myogenesis

Demethylation of histone lysines, one of the most important modifications in transcriptional regulation, is associated with various physiological states. KDM2B is a histone H3K4, H3K36, and H3K79 demethylase associated with the repression of transcription. Here, we present a novel mechanism by which KDM2B demethylates serum response factor (SRF) K165 to negatively regulate muscle differentiation, which is counteracted by histone methyltransferase SET7. We show that KDM2B inhibited skeletal muscle differentiation by inhibiting the transcription of SRF-dependent genes. Both KDM2B and SET7 regulated the balance of SRF K165 methylation. SRF K165 methylation was required for the transcriptional activation of SRF and for the promoter occupancy of SRF-dependent genes. SET7 inhibitors blocked muscle cell differentiation. Taken together, these data indicate that SRF is a non-histone target of KDM2B and that the methylation balance of SRF maintained by KDM2B and SET7 plays an important role in muscle cell differentiation.

developmental biology↗