Biology subjects

Panchal, M.

Publications and source records attributed to Panchal, M..

5 recordsLinked to original sources

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↗

bioRxiv2024

TREM1 disrupts myeloid bioenergetics and cognitive function in aging and Alzheimer disease models

Human genetics implicate defective myeloid responses in the development of late onset, age-associated Alzheimers disease (AD). Aging is characterized by a decline in myeloid metabolism that triggers maladaptive, neurotoxic immune responses. TREM1 is an amplifier of pro-inflammatory myeloid responses, and here we find that Trem1 deficiency prevents age-dependent changes in myeloid metabolism, inflammation, and hippocampal memory function. Trem1 deficiency rescues age-associated declines in ribose-5P, a glycolytic intermediate and the precursor for purine, pyrimidine, and NAD+ biosynthesis. In vitro, Trem1 deficient microglia are resistant to bioenergetic changes induced by amyloid-{beta}42 oligomers (A{beta}42), suggesting that A{beta}42 stimulation disrupts homeostatic microglial metabolism and immune function via TREM1. In the 5XFAD model of amyloid accumulation, Trem1 haploinsufficiency prevents spatial memory loss, preserves homeostatic microglial morphology, and reduces neuritic dystrophy independent of amyloid accumulation or changes in the disease-associated microglial transcriptomic signature. In aging APPSwe mice, Trem1 deficiency restores synaptic mitochondrial function and cerebral glucose uptake and prevents hippocampal memory decline. In post-mortem human brain, microglial TREM1 expression increases with clinical and neuropathological severity. Thus, TREM1-mediated disruption of myeloid metabolism, both in the periphery and brain, promotes cognitive decline in aging and amyloid accumulation, two major risk factors for AD development.

neuroscience↗

bioRxiv2020

Mass spectrometry imaging of phosphatidylcholine metabolism in lungs administered with therapeutic surfactants and isotopic tracers

Mass spectrometry imaging (MSI) visualises molecular distributions throughout tissues but is blind to dynamic metabolic processes. Here, MSI with high mass resolution together with multiple stable isotope labelling provided spatial analyses of phosphatidylcholine (PC) metabolism in mouse lungs. Dysregulated surfactant metabolism is central to many respiratory diseases. Metabolism and turnover of therapeutic pulmonary surfactants were imaged from distributions of intact and metabolic products of an added tracer, universally 13C-labelled dipalmitoyl PC (U[13C]DPPC). The parenchymal distributions of newly synthesised PC species were also imaged from incorporations of methyl-D9-choline. This dual labelling strategy demonstrated both lack of inhibition of endogenous PC synthesis by exogenous surfactant and location of acyl chain remodelling processes acting on the U[13C]DPPC-labelled surfactant, leading to formation of polyunsaturated PC lipids. This ability to visualise discrete metabolic events will greatly enhance our understanding of lipid metabolism in diverse tissues, and has potential application to both clinical and experimental studies.

biochemistry↗