Biology subjects

Yellajoshyula, D.

Publications and source records attributed to Yellajoshyula, D..

4 recordsLinked to original sources

bioRxiv2026

Lysosomal Glycosaminoglycan Catabolism Regulates Microglial Cell State in the Developing CNS

Remodeling of the extracellular matrix (ECM), a complex structural and signaling network of the nervous system, is essential for CNS development, plasticity, and injury responses, yet how individual neural cell types contribute to this process remains poorly understood. Here, we show that phagocytic clearance of glycosaminoglycans (GAGs), major components of the ECM, is an intrinsic function of microglia in the developing CNS. Our studies reveal an unexpected finding that impaired GAG clearance shifts microglia toward a non-homeostatic cell state seen in immature and disease-associated microglia (DAM), supporting a reciprocal relationship between the ECM and microglia. Using mouse models of Mucopolysaccharidosis VII, we examined the consequences of deleting {beta}-glucuronidase (GUSB), a lysosomal enzyme required for GAG degradation. Loss of GUSB causes early accumulation of undegraded chondroitin sulfate within microglial lysosomes, as confirmed by LC-MS analysis of intracellular GAGs isolated from cortical microglia. Single-cell RNA sequencing identified Gusb-null microglia as a distinct transcriptional population enriched for a core transcriptome shared by immature and disease-associated microglia. Together, these findings establish lysosomal GAG catabolism as a pathway that links ECM remodeling to the acquisition of adult homeostatic microglial identity during CNS development.

neuroscience↗

bioRxiv2021

A pathogenic DYT-THAP1 dystonia mutation causes hypomyelination and loss of YY1 binding

Dystonia is a disabling disease that manifests as prolonged involuntary twisting movements. DYT-THAP1 is an inherited form of isolated dystonia caused by mutations in THAP1 encoding the transcription factor THAP1. The phe81leu (F81L) missense mutation is representative of a category of poorly understood mutations that do not occur on residues critical for DNA binding. Here, we demonstrate that the F81L mutation (THAP1F81L) impairs THAP1 transcriptional activity and disrupts CNS myelination. Strikingly, THAP1F81L exhibits normal DNA binding but causes a significantly reduced DNA binding of YY1, its transcriptional partner that also has an established role in oligodendrocyte lineage progression. Our results suggest a model of molecular pathogenesis whereby THAP1F81L normally binds DNA but is unable to efficiently organize an active transcription complex.

neuroscience↗

bioRxiv2020

THAP1 Modulates Oligodendrocyte Maturationby Regulating ECM Degradation in Lysosomes

Mechanisms controlling myelination during CNS maturation play a pivotal role in the development and refinement of CNS circuits. The transcription factor THAP1 is essential for timing the inception of myelination during CNS maturation through a cell-autonomous role in the oligodendrocyte lineage. Here, we demonstrate that THAP1 modulates ECM composition by regulating glycosaminoglycan (GAG) catabolism within oligodendrocyte progenitor cells (OPCs). Thap1-/- OPCs accumulate and secrete excess GAGs, inhibiting their maturation through an auto-inhibitory mechanism. THAP1 controls GAG metabolism by binding to and regulating the GusB gene encoding {beta}-glucuronidase, a GAG-catabolic lysosomal enzyme. Applying GAG-degrading enzymes or overexpressing {beta}-glucuronidase rescues Thap1-/- OL maturation deficits in vitro and in vivo. Our studies establish lysosomal GAG catabolism within OPCs as a critical mechanism regulating oligodendrocyte development.

neuroscience↗

bioRxiv2020

Altered Capicua expression drives regional Purkinje neuron vulnerability through ion channel gene dysregulation in Spinocerebellar ataxia type 1

Selective neuronal vulnerability in neurodegenerative disease is poorly understood. Using the ATXN1[82Q] model of spinocerebellar ataxia type 1 (SCA1), we explored the hypothesis that regional differences in Purkinje neuron degeneration could provide novel insights into selective vulnerability. ATXN1[82Q] Purkinje neurons from the anterior cerebellum were found to degenerate earlier than those from the nodular zone, and this early degeneration was associated with selective dysregulation of ion channel transcripts and altered Purkinje neuron spiking. Efforts to understand the basis for selective dysregulation of channel transcripts revealed modestly increased expression of the ATXN1 corepressor Capicua (Cic) in anterior cerebellar Purkinje neurons. Importantly, lentiviral overexpression of Cic in the nodular zone accelerated both aberrant Purkinje neuron spiking and neurodegeneration. These findings reinforce the central role for Cic in SCA1 cerebellar pathophysiology and suggest that only modest reductions in Cic are needed to have profound therapeutic impact in SCA1.

neuroscience↗