Biology subjects

Wong, J. K.

Publications and source records attributed to Wong, J. K..

7 recordsLinked to original sources

bioRxiv2026

Pallidal beta oscillations underlying locomotor adaptation in Parkinsons disease

BackgroundLocomotor adaptation is essential for adjusting walking patterns to complex environments. This study investigated locomotor adaptation deficits in people with Parkinsons disease (PD) and examined oscillatory activity in the globus pallidus internus (GPi) during walking adaptation. We hypothesized that elevated beta-band activity in the GPi is associated with reduced locomotor adaptability in PD. MethodsTwelve PD patients with GPi deep brain stimulation (DBS) (eleven bilateral and one unilateral) were included. Local field potentials (LFPs) were recorded from DBS electrodes during split-belt treadmill walking. Patients were tested in the medication-off, DBS-off state. Locomotor adaptation was measured as the change in step length asymmetry during split-belt walking, with smaller changes indicating greater adaptation deficits. ResultsWe found that GPi high beta (20-30 Hz) and low gamma (30-60 Hz) oscillations were modulated during split-belt walking. Compared to adapters, non-adapters showed decreased movement-related beta suppression during walking. Across participants, beta activity in the GPi contralateral to the fast leg was negatively associated with adaptation magnitude (Spearmans {rho} = -0.65 to -0.75). ConclusionsGPi oscillations are dynamically modulated during locomotor adaptation in PD. Increased beta activity may underlie impaired sensorimotor adaptation during walking. These findings provide novel insight into basal ganglia mechanisms of gait adaptation in PD and suggest that elevated GPi beta activity may serve as a marker of locomotor adaptation deficits.

neuroscience↗

bioRxiv2025

AAV-Delivered Anti-PC-OxPL Antibody Fragments: A NovelTherapeutic Approach to Target ALS

Amyotrophic lateral sclerosis (ALS) is characterized by the progressive loss of motor neurons and premature death. The limited understanding of the mechanisms underlying selective motor neuron death has significantly hindered the development of disease-modifying treatments. Ferroptosis, a form of cell death dependent on iron accumulation, has been implicated in the selective degeneration of motor neurons in ALS. Oxidized phosphatidylcholines (PC-OxPL) have been identified as key effectors in the pathophysiological processes associated with this pathway. Preclinical observations revealed a distinct PC-OxPL profile in the cerebrospinal fluid (CSF) of sporadic ALS (sALS) patients and identified apolipoprotein E (APOE) particles as the primary carriers of PC-OxPL in the CSF. Furthermore, in ALS brain and spinal cord tissue sections, PC-OxPL was found to be predominantly associated with motor neurons. Exposure of iPSC-derived motor neurons to PC-OxPL led to transcriptomic changes in genes known to be linked to ALS, as well as the induction of significant TDP-43 pathology and motor neuron death. To counter this, we developed a single-chain antibody fragment (scFv) encoded by an AAV-delivered DNA construct that specifically targets PC-OxPL neoepitopes (PC-OxPL-VecTab(R)). PC-OxPL-VecTab(R) effectively neutralized PC-OxPL-induced neurotoxicity and TDP-43 aggregation in motor neurons, while preventing motor neuron death and deficits in a sALS CSF mouse model. When administered intrathecally to minipigs, PC-OxPL-VecTab(R) was distributed to both upper and lower motor neurons and expressed at levels predicted to be therapeutically effective. Our work identifies PC- OxPL as a critical pathological factor and a key inducer of TDP-43 pathology in ALS, providing the foundation for a novel therapeutic intervention modality for patients with sALS. Furthermore, it offers the exciting potential to be expanded to diseases characterized by PC-OxPL neurotoxicity.

neuroscience↗

bioRxiv2024

HIV-SEQ REVEALS GLOBAL HOST GENE EXPRESSION DIFFERENCES BETWEEN HIV-TRANSCRIBING CELLS FROM VIREMIC AND SUPPRESSED PEOPLE WITH HIV

"Active" reservoir cells transcribing HIV can perpetuate chronic inflammation in virally suppressed people with HIV (PWH) and likely contribute to viral rebound after antiretroviral therapy (ART) interruption, so they represent an important target for new therapies. These cells, however, are difficult to study using single-cell RNA-seq (scRNA-seq) due to their low frequency and low levels of HIV transcripts, which are usually not polyadenylated. Here, we developed "HIV-seq" to enable more efficient capture of HIV transcripts - including non-polyadenylated ones - for scRNA-seq analysis of cells from PWH. By spiking in a set of custom-designed capture sequences targeting conserved regions of the HIV genome during scRNA-seq, we increased our ability to find HIV RNA+ cells from PWH by up to 44%. Implementing HIV-seq in conjunction with surface phenotyping by CITE-seq on paired blood specimens from PWH before vs. after ART suppression, we found that HIV RNA+ cells were enriched among T effector memory (Tem) cells during both viremia and ART suppression, but exhibited a cytotoxic signature during viremia only. By contrast, HIV RNA+ cells from the ART-suppressed timepoints exhibited a distinct anti-inflammatory signature involving elevated TGF-{beta} and diminished IFN signaling. Overall, these findings demonstrate that active reservoir cells exhibit transcriptional features distinct from HIV RNA+ cells during viremia, and underscore HIV-seq as a useful tool to better understand the mechanisms by which HIV-transcribing cells can persist during ART.

immunology↗

bioRxiv2024

Pulsed low-dose-rate radiation (PLDR) reduces the tumor-promoting responses induced by conventional chemoradiation in pancreatic cancer-associated fibroblasts

Pancreatic cancer is becoming increasingly deadly, with treatment options limited due to, among others, the complex tumor microenvironment (TME). This short communications study investigates pulsed low-dose-rate radiation (PLDR) as a potential alternative to conventional radiotherapy for pancreatic cancer neoadjuvant treatment. Our ex vivo research demonstrates that PLDR, in combination with chemotherapy, promotes a shift from tumor-promoting to tumor-suppressing properties in a key component of the pancreatic cancer microenvironment we called CAFu (cancer-associated fibroblasts and selfgenerated extracellular matrix functional units). This beneficial effect translates to reduced desmoplasia (fibrous tumor expansion) and suggests PLDRs potential to improve total neoadjuvant therapy effectiveness. To comprehensively assess this functional shift, we developed the HOST-Factor, a single score integrating multiple biomarkers. This tool provides a more accurate picture of CAFu function compared to individual biomarkers and could be valuable for guiding and monitoring future therapeutic strategies. Our findings support the ongoing NCT04452357 clinical trial testing PLDR safety and TME normalization potential in pancreatic cancer patients. The HOST-Factor will be used in samples collected from this trial to validate its potential as a key tool for personalized medicine in this aggressive disease.

cancer biology↗

bioRxiv2021

Single cell multi-omics analysis of chromothriptic medulloblastoma highlights genomic and transcriptomic consequences of genome instability

Chromothripsis is a form of genome instability, whereby a presumably single catastrophic event generates extensive genomic rearrangements of one or few chromosome(s). However, little is known about the heterogeneity of chromothripsis across different clones from the same tumor, as well as changes in response to treatment. We analyzed single-cell genomic and transcriptomic alterations linked with chromothripsis in human p53-deficient medulloblastoma (n=7). We reconstructed the order of somatic events, identified early alterations likely linked to chromothripsis and depicted the contribution of chromothripsis to malignancy. We characterized subclonal variation of chromothripsis and its effects on double-minute chromosomes, cancer drivers and putatively druggable targets. Furthermore, we highlighted the causative role and the fitness consequences of specific rearrangements in neural progenitors. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=85 SRC="FIGDIR/small/449944v1_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@9d30e4org.highwire.dtl.DTLVardef@1f4d34eorg.highwire.dtl.DTLVardef@5cd50corg.highwire.dtl.DTLVardef@a71a81_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2021

Novel RT-ddPCR assays for determining the transcriptional profile of SARS-CoV-2

The exact mechanism of coronavirus replication and transcription is not fully understood; however, a hallmark of coronavirus transcription is the generation of negative-sense RNA intermediates that serve as the templates for the synthesis of positive-sense genomic RNA (gRNA) and an array of subgenomic mRNAs (sgRNAs) encompassing sequences arising from discontinuous transcription. Existing PCR-based diagnostic assays for SAR-CoV-2 are qualitative or semi-quantitative and do not provide the resolution needed to assess the complex transcription dynamics of SARS-CoV-2 over the course of infection. We developed and validated a novel panel of specially designed SARS-CoV-2 ddPCR-based assays to map the viral transcription profile. Application of these assays to clinically relevant samples will enhance our understanding of SARS-CoV-2 replication and transcription and may also inform the development of improved diagnostic tools and therapeutics. HighlightsO_LIWe developed a novel panel of 7 quantitative RT-ddPCRs assays for SARS-Cov-2 C_LIO_LIOur panel targets nongenic and genic regions in genomic and subgenomic RNAs C_LIO_LIAll assays detect 1-10 copies and are linear over 3-4 orders of magnitude C_LIO_LIAll assays correlated with the clinical Abbott SARS-CoV-2 Viral Load Assay C_LIO_LIClinical samples showed higher copy numbers for targets at the 3 end of the genome C_LI

microbiology↗

bioRxiv2018

Artesunate pErk up HepG2 cells to die through apoptosis in vitro

The dilemma between in vitro and in vivo drug screening results persisted to hinder preclinical anti-cancer drug development. In this study, drug screening was initially performed on monolayer cultures of HepG2 cells, whereas in vivo drug testing was performed on the subcutaneous xenograft mouse model of HepG2 cells in athymic nude mice. Results showed that Artesunate inhibited HepG2 cell growth in vitro, but was ineffective in vivo. Hence, we investigated the difference between in vitro and in vivo settings using this cell-drug combination as a model. Immuno-staining of hepatocellular carcinoma (HCC) biomarkers showed that -fetoprotein (AFP) was unaffected by Artesunate treatment in vitro or in vivo, suggesting that AFP was neither a biomarker nor response indicator. Alternatively, high albumin was detected in both monolayer and organoid cultures; contrariwise, the xenograft tumors prevailed low albumin, in consistency to human HCC with poor prognosis. Artesunate treatment reduced intracellular albumin expression in vitro; Artesunate did not alter tissue and serum albumin in xenograft mice, in coincidence with its irresponsiveness in vivo. However, Artesunate binding to albumin was undetectable. Instead, we observed a transient stimulation of Erk1/2 phosphorylation followed by DAPK1 dephosphorylation and apoptosis. Combined treatment of Artesunate with U0126 revoked Erk1/2-DAPK1 phosphorylation and exerted modest proliferative advantage at early time points, but eventually did not rescue HepG2 cells from death. U0126 induced multiploid formation independent of Artesunate, resulting in cell cycle arrest within 24 h post-treatment.\n\nSignificanceSystematic investigation of HCC biomarkers AFP and albumin among the in vitro models of monolayer and organoid cultures, and the in vivo models of subcutaneous and liver implantation xenograft mice was conducted.

cell biology↗