Biology subjects

Cho, W. J.

Publications and source records attributed to Cho, W. J..

11 recordsLinked to original sources

bioRxiv2026

LRRC57/RABIN is a presynaptic inhibitor of Rab GTPases in glutamatergic neurons

Synaptic vesicle cycling, if not properly constrained, can result in excessive neurotransmitter release and subsequent neural pathology. Rab GTPases orchestrate synaptic vesicle trafficking through GTP-dependent interactions with effector proteins, but the restraining mechanism of these interactions is unknown. Here we identify LRRC57 (or RABIN for RAB INhibitor), a conserved brain-enriched protein in glutamatergic synapses that binds multiple GTP-loaded synaptic Rabs and competitively blocks access to their effectors. Loss of Rabin increased glutamate release, expanded vesicle pools, accelerated vesicle turnover, and produced circuit hyperexcitability with epileptiform activity, which was mitigated by an antiepileptic agent that targets presynaptic function. Conversely, overexpression of the Rabin gene suppressed neurotransmitter release and protected against induced seizures and persistent epileptiform discharges. Together, these findings define a noncanonical decoy-effector mechanism that constrains presynaptic Rab signaling to preserve excitatory circuit stability.

neuroscience↗

bioRxiv2026

Alternative organelle targeting of OPA1 mediates fatty acid release from lipid droplets

Mitochondria and lipid droplets (LDs) are functionally coupled to coordinate fatty acid utilization and storage. However, a comprehensive understanding of mitochondria-LD alliances remains elusive. We have identified a previously unrecognized role for optical atrophy 1 (OPA1), a mitochondrial fusion factor, in the regulation of fatty acid release from LDs. We demonstrated that OPA1s exon 4 adapts an amphipathic helix to target OPA1 to LDs. OPA1 localized to LDs promote fatty acid release by facilitating the recruitment of lipases to LDs. In addition, OPA1s residence on LDs competes with its mitochondrial entry, influencing mitochondria fusion and connectivity. Furthermore, the S158N polymorphism within OPA1s exon 4 exhibiting attenuated fatty acid release from LDs is associated with changes in metabolic traits in pediatric cancer survivors. Altogether, our findings reveal that OPA1 actively mediates fatty acid release from LDs and provide a mechanistic link between OPA1 and human metabolism.

cell biology↗

bioRxiv2026

Virtual multiplex staining of the pancreatic islets across type 1 diabetes progression using a Schroedinger bridge

Classical hematoxylin and eosin (H&E) staining enables review of tissue morphology but lacks information regarding the molecular state of cells. Immunohistochemical (IHC) techniques label specific proteins in tissue, allowing differentiation of relevant structures that may go undetectable in H&E. However, the IHC process is complex, expensive, and time-consuming, especially for multiplex IHC (mIHC) limiting its use in large cohorts. Stain conversion of H&E to IHC using generative artificial intelligence models such as generative adversarial networks (GANs) represent one solution to this problem. However, GANs are unstable during out of distribution sampling and are prone to hallucinations or mode collapse, limiting their accuracy in challenging image conversion tasks. To address this, the field has recently turned to diffusion models. Here, we introduce Schrodinger-bridge for Multiplex ImmunoLabel Estimation (SMILE). Unlike conventional diffusion models that map from source to target through an intermediate Gaussian noise, Schrodinger-bridge diffusion models skip this step and have been shown to better preserve structures during image translation. To test the performance of SMILE, we generated a large cohort of high-fidelity H&E-mIHC image pairs from pancreatic organ donors, targeting insulin, glucagon, and CD3. Our dataset well-sampled across type-1 diabetes status, pancreas anatomical location, age, and sex. Using this cohort, we demonstrate the superiority of SMILE compared to GANs via a comprehensive evaluation framework incorporating texture, distribution, and antibody-specific metrics, as well as blinded pathologist reviews. We further confirmed the ability of SMILE to generate accurate mIHC images from H&Es generated at an external site, to perform whole slide image conversion, and to generate realistic three-dimensional maps of the pancreatic islets in non-diabetic, auto-antibody positive, and type-1 diabetic donor tissue. Finally, we performed stain conversion of paired H&E to HER2 and Ki67 images in breast cancer, confirming the superiority of SMILE in diverse stain conversion applications. Collectively, this framework provides a scalable pipeline for high-throughput proteomic inference from archival H&Es, providing transformative potential for pancreatic research and digital pathology.

bioinformatics↗

bioRxiv2025

Porosome reconstitution reverses Alzheimers in human brain organoids

A central challenge in overcoming diseases resulting from defects in the cellular nanoscale multiprotein porosome complexes, is the consequent alteration of other proteins within the complex. By exploiting the distinct porosomes present in different tissues, Porosome Therapeutics, Inc., has developed a clinically relevant approach to incorporate (reconstitute) functional wild type porosomes into the plasma membrane of diseased cells to overcome secretory defects. In a combinatorial strategy of reprogramming the neuronal secretory and metabolic components, we established a dual-target therapeutic framework that repairs synaptic and metabolic defects to counteract neurodegeneration in Alzheimers. Utilizing iPSC derived human brain organoids, as recommended by the NIH and FDA, we demonstrate both the morphological and functional reversal of Alzheimers following porosome-apigenin treatment. Using the UHD-CMOS-MEA System developed jointly by Sony Semiconductor Solutions (Sony), SCREEN Holdings (SCREEN) and VitroVo, we were able to monitor thousands of neuronal firing in the brain organoids, helping in assessing the restoration of neuronal function in Alzheimers following porosome-apigenin therapy.

neuroscience↗

bioRxiv2025

Mechanism of clinically relevant neurosecretory and metabolic impairment in Alzheimers and identification of engineered nanotherapy

A central challenge in Alzheimers disease is understanding the mechanism of neuronal secretory dysfunction. By exploiting AI, we reveal how beta-amyloid disrupts key protein interactions within the neuronal secretory machinery. In a combinatorial strategy of reprogramming the neuronal secretory and metabolic components, we established a dual-target therapeutic framework that repairs synaptic and mitochondrial defects to counteract neurodegeneration in Alzheimers.

neuroscience↗

bioRxiv2024

Reprogramming the neuronal secretory and metabolic machinery using correctors for Alzheimer therapy

Alzheimer disease (AD) is a neurodegenerative disorder characterized by memory loss and personality changes, leading to dementia. The primary cause of the cognitive decline that characterizes AD is the loss of neurons, hypothesized as being due to secretory defects in neurotransmitter release and synaptic plasticity. There is growing evidence that in Alzheimer there is impaired neuronal metabolism due to an increase in free radicals and mitochondrial fission, leading to loss in ATP synthesis required for neurotransmission. Therefore, impaired metabolism in neurons may lead to the observed defects in neurotransmitter release, resulting in the loss of neuronal function and connections in regions of the brain involved in memory and reasoning. In our earlier studies, peptide inhibitor targeting oligomeric ATAD3A, a protein essential for mitochondrial fission and bioenergetics, were found to partially rescue from AD, both in AD neurons and AD mice. In the current study in AD neurons, neuronal porosome reconstitution combined with either a linear or circular peptide inhibitor of ATAD3A oligomers, was able to restore AD neurons to near normal levels of viability and greatly reduce oxidative stress in mitochondria. Additionally, the peptide and a small molecule considered safe by the FDA and used as a food additive, were also able to greatly increase viability in AD neurons and provide reduction to near normal levels of mitochondrial oxidative stress. Collectively, these results demonstrate great promise as secretory and metabolic correctors for AD therapy.

neuroscience↗

bioRxiv2024

Porosome reconstitution therapy: A biologic rescue from cystic fibrosis

Cystic fibrosis (CF) is a genetic disorder resulting from mutations in the CF Transmembrane Conductance Regulator (CFTR) gene that codes for a chloride transporting channel at the cell plasma membrane. In CF, highly viscous mucus is secreted in the airways preventing its clearance, leading to lung infections and respiratory failure. A major challenge in treating CF patients has been the presence of more than 2,000 different CFTR mutations or due to the absence of CFTR expression. CFTR is among the 34 major proteins composing the 100 nm porosome secretory machinery in the human airway epithelia, involved in mucin secretion. The airways is coated with a thin film of mucus, composed primarily of mucin MUC5AC and MUC5B. Sputum from patients with CF show a >70% decrease in MUC5B and MUC5AC secretion. Our studies using differentiated 3D cultures of human airway epithelial cell line, also demonstrate loss of both chloride and mucus secretion following exposure to CFTR inhibitors thiazolidinone 172 or the hydrazide GlyH101. Our studies show that human bronchial epithelial (HBE) cells with {Delta}F508 CFTR mutation, affects nearly a dozen porosome proteins including CFTR. Therefore, we hypothesized that the introduction of normal functional porosomes carrying wild type CFTR into the cell plasma membrane of CF cells would rescue from all forms of CF. Air liquid interface (ALI) 3D differentiated HBE WT-CFTR cells and {Delta}F508-CFTR CF HBE cell cultures mimicking normal lung physiology, responding to CFTR inhibitors and CF corrector and modulator drugs Tezacaftor, Ivacaftor and TRIKAFTA, was used in the study. Introduction of functional porosome complexes obtained from WT-CFTR HBE cells into the plasma membrane (PM) of {Delta}F508-CFTR CF cells, was demonstrated by an increase in PM-associated CFTR using Magnify expansion microscopy. Mucin secretion assays demonstrate porosome reconstitution to restore mucin secretion more than twice as effectively as TRIKAFTA. These results are further supported by preliminary nasal potential different studies in {Delta}F508 mice, where treatment of the nasal passage with porosome isolates from WT-CFTR HBE cells, restore chloride secretion in the nasal passage of mice, a further validation of the highly effective porosome reconstitution therapy for CF.

cell biology↗

bioRxiv2023

Reprogramming the cells secretory machinery: A cystic fibrosis rescue

Cystic fibrosis (CF) is a genetic disorder resulting in the secretion of highly viscous mucus in the airways, leading to lung infection, respiratory failure, morbidity and mortality. CF is attributed to mutation in the CF Transmembrane Conductance Regulator (CFTR) gene that codes for a chloride transporting channel at the cell plasma membrane. More than 2,000 mutations in the CF gene have been identified; however, the {Delta}F508 CFTR is the most common, accounting for approximately 70% of all CFTR mutations. Our earlier studies demonstrate the CFTR protein to be among the nearly 30 proteins constituting the porosome secretory machinery at the plasma membrane in human airway epithelial mucous-secreting cells. Additionally, our recent studies show that stimulated human airway epithelial cells pre-exposed to CFTR inhibitors result in loss of mucus secretion, suggesting the involvement of CFTR in porosome-mediated mucus secretion. To further test the hypothesis that CFTR is involved in porosome-mediated mucus secretion in the human airways, and to develop a therapeutic approach to overcome this defect in {Delta}F508 CFTR human bronchial epithelial cells, the current study was undertaken. Mass spectrometry and Western Blot analysis of porosomes isolated from WT-CFTR Human Bronchial Epithelial (HBE) Cells and {Delta}F508-CFTR CF HBE cells, demonstrate a varying loss or gain of several porosome proteins, including a decrease in the t-SNARE protein SNAP-23 and undetectable levels of the Ras GTPase activating like-protein IQGAP1 in the {Delta}F508-CFTR CF cells. This suggested that mutation in porosome-associated CFTR protein additionally affects other proteins within the porosome secretory machinery, negatively impacting mucus secretion. Hence, to ameliorate defects in mucus secretion in CF, the reconstitution of functional porosomes obtained from WT-CFTR HBE cells into the plasma membrane of {Delta}F508-CFTR mutant cells was performed. Results from the study demonstrate that porosome reconstitution rescues mucus secretion approximately four-fold more effectively than the currently available CF drugs Tezacaftor and Ivacaftor.

cell biology↗

bioRxiv2023

A fluorogenic complementation tool kit for interrogating lipid droplet-organelle interaction

Contact sites between lipid droplets and other organelles are essential for cellular lipid and energy homeostasis. Detection of these contact sites at nanometer scale over time in living cells is challenging. Here, we developed a tool kit for detecting contact sites based on Fluorogen- Activated Bimolecular complementation at CONtact sites, FABCON, using a reversible, low affinity split fluorescent protein, splitFAST. FABCON labels contact sites with minimal perturbation to organelle interaction. Via FABCON, we quantitatively demonstrated that endoplasmic reticulum (ER)- and mitochondria (mito)-lipid droplet contact sites are dynamic foci in distinct metabolic conditions, such as during lipid droplet biogenesis and consumption. An automated analysis pipeline further classified individual contact sites into distinct subgroups based on size, likely reflecting differential regulation and function. Moreover, FABCON is generalizable to visualize a repertoire of organelle contact sites including ER-mito. Altogether, FABCON reveals insights into the dynamic regulation of lipid droplet-organelle contact sites and generates new hypotheses for further mechanistical interrogation during metabolic switch.

cell biology↗

bioRxiv2022

Possible Mechanism of Porosome-Mediated Exosome Release

Supramolecular cup-shaped lipoprotein structures called porosomes embedded in the cell plasma membrane mediate fractional release of intra-vesicular contents from cells during secretion. The presence of porosomes, have been documented in many cell types including neurons, acinar cells of the exocrine pancreas, growth hormone secreting cells of the pituitary, and mouse insulin-secreting beta cell insulinomas called Min6. Electron micrographs of the nerve terminal in rat brain and of Min6 cells, suggest that besides the docking, fusion and content release of neurotransmitter containing synaptic vesicles and insulin containing granules, multi-vesicular bodies and exosome-like vesicles are released at the porosome complex. To test this hypothesis, the porosome-associated calcium transporting ATPase 1 [SPCA1] encoded by the ATP2C1 gene, was knocked-out in Min6 cells using CRISPR, to study glucose-stimulated insulin and exosome release. In agreement with electron micrographs, results from the study demonstrate a loss of both glucose-stimulated insulin and exosome release in the ATP2C1 knockout Min6 cells. These results further confirm the role of the porosome complex in insulin secretion and establishes a new paradigm in porosome-mediated exosome release in beta cells of the endocrine pancreas.

cell biology↗

bioRxiv2017

Induction of differentiation and metabolic reprogramming in human hepatoma cells by adult human serum

Tissue culture medium routinely contains fetal bovine serum (FBS). Here we show that culturing human hepatoma cells in their native, adult serum (human serum, HS) results in the restoration of key morphological and metabolic features of normal liver cells. When moved to HS, these cells show differential transcription of 22-32% of the genes, stop proliferating, and assume a hepatocyte-like morphology. Metabolic analysis shows that the Warburg-like metabolic profile, typical for FBS-cultured cells, is replaced by a diverse metabolic profile consistent with in vivo hepatocytes. We demonstrate the formation of large lipid and glycogen stores, increased glycogenesis, increased {beta}-oxidation, increased ketogenesis, and decreased glycolysis. Finally, organ-specific functions are restored, including xenobiotics degradation and secretion of bile, very low density lipoprotein, and albumin. Thus, organ-specific functions are not necessarily lost in cell cultures, but might be merely suppressed in FBS. Together, we showed that cells that are representative of normal physiology can be produced from cancer cells simply by replacing FBS by HS in culture media. The effect of serum is often overseen in cell culture and we provide a detailed study in the changes that occur, provide insight in some of the serum components that may play a role in the establishment of the different phenotypes, and discuss how these finding might be beneficial to a variety of research fields.

cell biology↗