Biology subjects

Park, K. K.

Publications and source records attributed to Park, K. K..

5 recordsLinked to original sources

bioRxiv2026

Total RNA Sequencing Reveals Early Coding, Noncoding, and Isoform-Level Transcriptomic Changes Following Traumatic and Glaucomatous Optic Nerve Injury

Purpose: Retinal ganglion cell (RGC) death following optic nerve injury is driven by transcriptional programs involved in apoptosis, neuroinflammation, and other regulated cell death pathways; however, the early transcriptomic changes initiating these processes remain poorly defined. We used rRNA-depleted total RNA sequencing to characterize early alterations in protein-coding genes, long noncoding RNAs (lncRNAs), and alternative splicing events in mouse retinas following optic nerve crush (ONC) and silicone oil-induced ocular hypertension under-detected (SOHU), prior to substantial RGC loss. Methods: Whole retinas were collected 6 hours after ONC and 5 days after SOHU induction. Differentially expressed protein-coding genes and lncRNA-classified transcripts were identified using total RNA sequencing, followed by functional enrichment, lncRNA-associated pathway analysis, alternative splicing analysis, and fluorescent in situ hybridization (FISH) validation. Results: In SOHU retinas, hundreds of protein-coding genes and lncRNA-classified transcripts were differentially expressed, with enrichment of immune activation, extracellular matrix remodeling, complement, phagocytic signaling, and suppression of mitochondrial energy metabolism pathways. Similarly, in ONC retinas, many protein-coding genes and lncRNA-classified transcripts were differentially expressed, with a prominent chemokine, cytokine-dominant inflammatory response. FISH validation supported injury-associated upregulation of Prss56 and Lif. Both injury models exhibited substantial transcript-level alterations, with widespread alternative splicing changes detected. Conclusions: Early optic nerve injury induces rapid transcriptional changes involving protein-coding genes, lncRNAs, and transcript isoform regulation before substantial RGC loss. These findings highlight early alterations in both coding and noncoding RNA landscapes following retinal injury and provide a valuable resource of candidate genes and pathways for future validation in RGC degeneration and neuroprotection.

neuroscience↗

bioRxiv2026

Comparative Evaluation of Adeno-Associated Virus and Lentivirus Mediated Gene Transfer in Adult Rat Optic Nerve

BackgroundThe optic nerve serves as a vital conduit for visual signaling, and its degeneration in optic neuropathy results in irreversible vision loss. It is also a widely used model for studying central nervous system (CNS) injury and repair. Although adeno-associated virus (AAV) and lentivirus are extensively applied in CNS research, their transduction efficiency and cell-type specificity within the optic nerve remain poorly characterized. This study aimed to identify the most effective viral vector, serotype, and promoter for direct gene delivery to the adult rat optic nerve. MethodsSprague-Dawley rats (7-10 weeks) received intra-optic nerve injections of lentiviral or AAV vectors encoding GFP under different promoters (CAG, CMV, or GFAP). Two to three weeks post-injection, optic nerves were collected for immunohistochemistry with markers of oligodendrocytes (Olig2), astrocytes (GFAP, Sox9), and microglia (IBA1). Transduction efficiency and cell-type specificity were assessed using confocal microscopy. ResultsAAV2, AAV5, and lentivirus showed minimal transduction, with only sparse GFP-positive cells observed near injection sites. In contrast, AAV-PHP.eB carrying the CAG promoter yielded robust and widespread GFP expression near the injection site. Quantitative analysis revealed that approximately 90% of transduced cells were Olig2-positive oligodendrocytes, indicating strong tropism for this glial population. ConclusionAAV-PHP.eB driven by the CAG promoter enables efficient gene delivery to the optic nerve, with a predominant tropism for oligodendrocytes. This targeted intra-optic nerve injection approach offers a reliable platform for manipulating oligodendrocytes and investigating mechanisms of CNS development, injury, and repair relevant to both optic neuropathies and other CNS diseases.

neuroscience↗

bioRxiv2026

Neuritin1 Cis-Regulatory Elements Enable Gene Expression Preferentially in Retinal Ganglion Cells

PurposeRetinal ganglion cells (RGCs) are essential for visual signal transmission, yet they are vulnerable to injury and degeneration. Gene modulation in RGCs using adeno-associated virus (AAV) offers a promising avenue for neuroprotection and regeneration, but promoters lack sufficient RGC specificity, limiting precision needed for preclinical studies. This study aims to identify novel promoter-enhancer combinations (PECs) to achieve gene expression preferentially in RGCs. MethodsWe evaluated existing transcriptomic data to identify Neuritin 1(Nrn1) as a gene with highly restricted RGC expression in the retina. Synthetic PECs derived from human and mouse Nrn1 loci were incorporated into AAV2 vectors driving expression of a nuclear-targeted reporter GreenLantern. AAVs were delivered via intravitreal injection into C57BL6/J mice, and transduction efficiency and RGC specificity were evaluated in both young and aged retinas and those subjected to intraorbital optic nerve crush (ONC), using immunohistochemistry and quantitative analysis of RBPMS+ cells. ResultsWe found that AAV2 with a human Nrn1 PEC drives gene expression in RGCs. Quantitative analysis revealed that over 83% of transduced cells were RBPMS-positive, indicating robust RGC selectivity and significantly outperforming ubiquitous promoters. Notably, the Nrn1 PEC retained strong and selective transgene expression in RGCs in aged mice and following ONC, demonstrating its resilience under aged and injury conditions. ConclusionThe Nrn1 PEC enables efficient and injury-resilient gene expression in RGCs, addressing a key limitation in cell-specific targeting. This AAV-incorporated PEC offers a robust platform for evaluating neuroprotective interventions and accelerates translational development of gene therapies for glaucoma and other optic neuropathies.

neuroscience↗

bioRxiv2026

AAV2-Retro-Mediated Gene Transfer Selectively Targets Outer Retinal Cells Following Intravitreal Injection

PurposeTo characterize the cellular tropism and temporal dynamics of adeno-associated virus 2 (AAV2)-retro-mediated gene delivery in the adult mouse retina following intravitreal injection. MethodsAdult C57BL/6J mice received single or sequential intravitreal injections of AAV2-retro carrying the mGreenLantern (mGL) reporter gene. Retinas were collected at 1-, 3-, and 14-days post-injection (dpi) and processed for immunofluorescence analysis. Transduced cell types were identified using cell-type markers, including cone arrestin, RBPMS, and AP-2. The number and distribution of mGL-positive cells were quantified on whole retinas or retinal cross-sections to assess transduction efficiency, specificity, and spatial coverage. ResultsReporter expression was detected in the outer retina at 1 dpi and increased markedly at 3 and 14 dpi. AAV2-retro demonstrated strong tropism for photoreceptors and retinal pigment epithelium (RPE), with robust labeling of both rods and cones. In contrast to the robust outer retinal expression, transduction in the inner nuclear layers was limited to a few retinal ganglion and amacrine cells, reflecting strong cell-type specificity. Reporter expression was distributed widely across the retina, exceeding the localized pattern typically observed following subretinal delivery with conventional AAV2 vectors. Sequential injections further increased reporter expression and spatial coverage compared with single injections. ConclusionsAAV2-retro enables efficient, outer retina-specific gene delivery following intravitreal administration. This approach overcomes the limitations of traditional intravitreal gene transfer and provides a minimally invasive alternative to subretinal injection. AAV2-retro- mediated transduction may facilitate preclinical studies of retinal degeneration and support the development of gene therapies aimed at preserving photoreceptors and RPE function.

neuroscience↗

bioRxiv2023

Single-Nucleus RNA Sequencing of Developing and Mature Superior Colliculus Identifies Neuronal Diversity and Candidate Mediators of Circuit Assembly

The superior colliculus (SC) is a sensorimotor structure in the midbrain that integrates input from multiple sensory modalities to initiate motor commands. It undergoes well-characterized steps of circuit assembly during development, rendering the mouse SC a popular model to study establishment and refinement of neural connectivity. Here we performed single nucleus RNA-sequencing analysis of the mouse SC isolated at various developmental time points. Our study provides a transcriptomic landscape of the cell types that comprise the SC across murine development with particular emphasis on neuronal heterogeneity. We used these data to identify Pax7 as a marker for an anatomically homogeneous population of GABAergic neurons. Lastly, we report a repertoire of genes differentially expressed across the different postnatal ages, many of which are known to regulate axon guidance and synapse formation. Our data provide a valuable resource for interrogating the mechanisms of circuit development, and identifying markers for manipulating specific SC neuronal populations and circuits.

neuroscience↗