Biology subjects

Geng, Y.

Publications and source records attributed to Geng, Y..

At least 37 records · Page 2Linked to original sources

bioRxiv2024

Efficient generation of CAR NK cells from human umbilical cord blood CD34+ stem and progenitors for democratizing affordable immunotherapy

Chimeric antigen receptor (CAR) natural killer cells (CAR NK) cells, leveraging safety and not requiring HLA match in adoptive infusion, have emerged as promising alternative cells to CAR-T cells for immunotherapies. High and multiple doses of CAR NK cell infusions are essential to maintain therapeutic efficacy in clinical trials. This requires efficient methods for generating large-scale CAR NK cells and significantly reducing CAR engineering costs. In this study, we develop a three-step strategy to generate highly high yields of induced NK (iNK) and CAR iNK cells from human umbilical cord blood CD34+ hematopoietic stem and progenitor cells (CD34+ HSPCs). Starting from a single umbilical cord blood CD34+ HSPC, our reliable method efficiently produces 14-83 million mature iNK cells or 7-32 million CAR iNK cells with high expression levels of CD16 and zero T cell contaminations. Introducing CAR expression elements at the HSPC level reduces the quantities of CAR pseudoviruses to 1 / 140.000 - 1 / 600,000 compared to engineering CARs in mature NK cells. The iNK and CAR iNK cells, including fresh cells and thawed cells from cryopreserved conditions, demonstrate remarkable tumoricidal activities against various human cancer cells and significantly prolong the survival of human tumor-bearing animals. The high yields of CAR NK cells and negligible costs of CAR engineering of our method support the broad applications of CAR NK cells for treating cancer patients.

cell biology↗

bioRxiv2024

APP beta-CTF triggers cell-autonomous synaptic toxicity independent of Abeta

A{beta} is believed to play a significant role in synaptic degeneration observed in Alzheimers disease (AD) and is primarily investigated as a secreted peptide. However, the contribution of intracellular A{beta} or other cleavage products of its precursor protein (APP) to synaptic loss remains uncertain. In this study, we conducted a systematic examination of their cell-autonomous impact using a sparse expression system. Here, these proteins/peptides were overexpressed in a single neuron, surrounded by thousands of untransfected neurons. Surprisingly, we found that APP induced dendritic spine loss only when co-expressed with BACE1. This effect was mediated by {beta}-CTF, a {beta}-cleavage product of APP, through an endosome-related pathway independent of A{beta}. Neuronal expression of {beta}-CTF in mouse brains resulted in defective synaptic transmission and cognitive impairments, even in the absence of amyloid plaques. These findings unveil a {beta}-CTF-initiated mechanism driving synaptic toxicity irrespective of amyloid plaque formation and suggest a potential intervention by inhibiting the endosomal GTPase Rab5.

neuroscience↗

bioRxiv2024

MicroRNA-26b protects against MASH development and can be efficiently targeted with lipid nanoparticles.

Background & AimsThe prevalence of metabolic dysfunction-associated steatohepatitis (MASH) is increasing, urging more research into the underlying mechanisms. MicroRNA-26b (miR-26b) might play a role in several MASH-related pathways. Therefore, we aimed to determine the role of miR-26b in MASH and its therapeutic potential using miR-26b mimic-loaded lipid nanoparticles (LNPs). MethodsApoe-/-Mir26b-/-, Apoe-/-LysMcreMir26bfl/fl mice, and respective controls were fed a western-type diet to induce MASH. Plasma and liver samples were characterized regarding lipid metabolism, hepatic inflammation, and fibrosis. Additionally, miR-26b mimic-loaded LNPs were injected in Apoe-/-Mir26b-/- mice to rescue the phenotype and key results were validated in human precision-cut liver slices. Finally, kinase profiling was used to elucidate underlying mechanisms. ResultsApoe-/-Mir26b-/- mice showed increased hepatic lipid levels, coinciding with increased expression of scavenger receptor a and platelet glycoprotein 4. Similar effects were found in mice lacking myeloid-specific miR-26b. Additionally, hepatic TNF and IL-6 levels and amount of infiltrated macrophages were increased in Apoe-/- Mir26b-/- mice. Moreover, Tgfb expression was increased by the miR-26b deficiency, leading to more hepatic fibrosis. A murine treatment model with miR-26b mimic-loaded LNPs reduced hepatic lipids, rescuing the observed phenotype. Kinase profiling identified increased inflammatory signaling upon miR-26b deficiency, which was rescued by LNP treatment. Finally, miR-26b mimic-loaded LNPs also reduced inflammation in human precision-cut liver slices. ConclusionsOverall, our study demonstrates that the detrimental effects of miR-26b deficiency in MASH can be rescued by LNP treatment. This novel discovery leads to more insight into MASH development, opening doors to potential new treatment options using LNP technology. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=100 SRC="FIGDIR/small/580792v2_ufig1.gif" ALT="Figure 1"> View larger version (21K): org.highwire.dtl.DTLVardef@b8b5b8org.highwire.dtl.DTLVardef@a26333org.highwire.dtl.DTLVardef@11ed2a0org.highwire.dtl.DTLVardef@963208_HPS_FORMAT_FIGEXP M_FIG C_FIG

pathology↗

bioRxiv2024

Restricted intake of sulfur-containing amino acids reversed the hepatic injury induced by excess Desulfovibrio through gut-liver axis

Gut-liver axis has been a study focus for liver diseases. Diet is a key player in influencing the gut microbiota. However, the effect of different dietary patterns on gut microbiota and liver functions remains unclear. Here, we used mouse standard chow and purified diet to mimic two common human dietary patterns: healthy grain and planted-based diet and Western style diet, respectively and explored their impacts on the gut microbiota and liver. Gut microbiota experienced a great shift with notable increase in Desulfovibrio, gut bile acid (BA) concentration elevated significantly, and liver inflammation was observed in mice fed with the purified diet. Liver inflammation due to translocation of toxic lipopolysaccharides (LPS) and hydrophobic BAs from the damaged gut barrier was also observed in mice fed with the chow diet after receiving Desulfovibrio desulfuricans ATCC 29577 (DSV). Restricted intake of sulfur-containing amino acids reversed the liver injury due to excess Desulfovibrio through lowering the gut BA concentration and enhancing the hepatic antioxidant and detoxifying ability. Ex vivo fermentation of human fecal microbiota with primary BAs also demonstrated that DSV enhanced production of secondary BAs. Germ-free mice had higher concentration of both conjugated and unconjugated primary BAs in their gut after receiving DSV.

microbiology↗

bioRxiv2023

Using population dynamics to count bacteriophages and their lysogens

Traditional assays for counting bacteriophages and their lysogens are labor-intensive and highly perturbative to the host cells. Here, we present a high-throughput infection method where all steps--cell growth, viral encounters, and post-infection recovery--take place in a microplate reader, and the growth dynamics of the infected culture are measured continuously using the optical density (OD). We find that the post-infection dynamics are reproducible and interpretable. In particular, the OD at which the culture lyses scales linearly with the logarithm of the initial phage concentration, providing a way of measuring phage numbers in unknown samples over nine decades and down to single-phage sensitivity. Interpreting the measured dynamics using a mathematical model for the coupled kinetics of phages and bacteria further allows us to infer the rates of viral encounters and cell lysis. Adding a single step of antibiotic selection provides the ability to measure the rate of host lysogenization. To demonstrate the application of our assay, we characterized the effect of bacterial growth rate on the propensity of lambda phage to lysogenize E. coli. When infected by a single phage, the probability of lysogenization is found to decrease approximately exponentially with the host growth rate. In growing, but not in stationary, cells, the propensity to lysogenize increases ~50-fold when multiple phages co-infect the cell. These findings illuminate how host physiology feeds into the lysis/lysogeny decision circuit, and demonstrate the utility of high-throughput infection to interrogating phage-host interactions.

microbiology↗

bioRxiv2023

SARS-CoV-2 Omicron infection augments the magnitude and durability of systemic and mucosal immunity in triple-dose CoronaVac recipients

BackgroundThe inactivated whole-virion vaccine, CoronaVac, is one of the most widely used coronavirus disease 2019 (COVID-19) vaccines worldwide. There is a paucity of data indicating the durability of the immune response and the impact of immune imprinting induced by CoronaVac upon Omicron breakthrough infection. MethodsIn this prospective cohort study, 41 recipients of triple-dose CoronaVac and 14 unvaccinated individuals were recruited. We comprehensively profiled adaptive immune parameters in both groups, including spike-specific immunoglobulin (Ig) G and IgA titers, neutralizing activity, B cells, follicular helper T (Tfh) cells, CD4+ and CD8+ T cells, and their memory subpopulations at 12 months after the third booster dose and at 4 weeks and 20 weeks after Omicron BA.5 infection. ResultsTwelve months after the third CoronaVac vaccination, spike-specific antibody and cellular responses were detectable in most vaccinated individuals. BA.5 infection significantly augmented the magnitude, cross-reactivity and durability of serum neutralization activities, Fc-mediated phagocytosis, and nasal spike-specific IgA responses, memory B cells, activated Tfh cells memory CD4+ T cells, and memory CD8+ T cells for both the ancestral strain and Omicron subvariants, compared to unvaccinated individuals. Notably, the increase in BA.5-specific immunity after breakthrough infection was consistently higher than for the ancestral strain, suggesting no evidence of immune imprinting. Immune landscape analyses showed vaccinated individuals have better synchronization of multiple immune components than unvaccinated individuals upon heterologous SARS-CoV-2 infection. ConclusionOur data provides detailed insight into the protective role of inactivated COVID-19 vaccine in shaping humoral and cellular immune responses to heterologous Omicron infection. Trial registrationClinicalTrials.gov NCT05680896 FundingThis study was supported by the National Natural Science Foundation of China (92269118, 92269205), Nanjing Important Science & Technology Specific Projects (2021-11005), Scientific Research Project of Jiangsu Health Commission (M2022013), Clinical Trials from the Affiliated Drum Tower Hospital, Medical School of Nanjing University (2021-LCYJ-PY-9), and Jiangsu graduate practice innovation project (JX22013929).

immunology↗

bioRxiv2023

O-GlcNAcylation of YTHDF2 antagonizes ERK-dependent phosphorylation and inhibits lung carcinoma

The intracellular O-linked N-acetylglucosamine (O-GlcNAc) glycosylation mediates many signal transduction events and regulates tumorigenesis. Previously the RNA N6-methyladenosine (m6A) reader, YTH (YT521-B homology) domain 2 (YTHDF2), has been shown to be O-GlcNAcylated on Ser-263 during Hepatitis B virus (HBV) infection and promote HBV-related hepatocellular carcinoma. Herein we mapped YTHDF2 O-GlcNAcylation at Thr-49 via electron-transfer dissociation mass spectrometry under unperturbed conditions. We show that YTHDF2 Thr-49 O-GlcNAcylation antagonizes Extracellular-signal regulated kinase (ERK)-dependent phosphorylation at Ser-39 and promotes YTHDF2 degradation. The downstream signaling pathway of YTHDF2 in lung carcinoma are thus upregulated, which leads to the downregulation of c-Myc. We further used mouse xenograft models to show that YTHDF2-T49A mutants increased lung cancer mass and size. Our work reveals a key role of YTHDF2 O-GlcNAcylation in tumorigenesis and suggests that O-GlcNAcylation exerts distinct functions under different biological stress.

biochemistry↗

bioRxiv2023

Metabolic Nutrient Preferences of Vibrio mimicus: Leveraging Nucleotides and Oligopeptides from Yellow Catfish for Enhanced Infectivity

In the context of host-microbe interactions, the microenvironment plays a critical role in facilitating microbial survival, and variations in these microenvironments may influence the pathogenicity of microorganisms. Vibrio mimicus, a major pathogen responsible for infections in aquatic animals, poses a substantial threat to yellow catfish (Pelteobagrus fulvidraco) and grass carp (Ctenopharyngodon idella), two naturally occurring hosts displaying markedly different susceptibility levels. This study aims to unravel the underlying mechanisms behind this susceptibility discrepancy in the two teleost species. Employing metabolomic analysis, we identified a distinctive microenvironment in yellow catfish, characterized by abundant purine nucleotides and oligopeptides. Furthermore, a total of 67 specific metabolites were identified from both yellow catfish and grass carp, with 33 displaying heightened expression on the body surface of yellow catfish, including nucleotides, amino acids, and gangliosides, while 34 were predominantly expressed on the body surface of grass carp, primarily comprising lipids. Subsequent investigations revealed that certain compounds related to nucleotides and oligopeptides exhibited significant growth-promoting effects and were utilized by V. mimicus as nutrients, with deoxyguanosine proving to be notably more than twice as effective as glucose. Moreover, during V. mimicus infection, numerous metabolites such as oligopeptides, purine nucleotides, and specific metabolites experienced considerable depletion in the skin of yellow catfish. Concurrently, several genes associated with nucleosidase and peptidase were upregulated in the skin and muscles of infected fish. These findings suggest that the microenvironment provided by different hosts plays a pivotal role in determining the infectivity of the pathogen. Additionally, our results indicate that the microenvironment on the surface of yellow catfish, characterized by an abundance of purine nucleotides and oligopeptides, indirectly enhances V. mimicus growth, ultimately augmenting its infectivity.

microbiology↗

bioRxiv2023

Skin permeable polymer for noninvasive transdermal insulin delivery

Subcutaneous injection of insulin is the current standard medication for many diabetic patients. Convenient and painless noninvasive transdermal insulin delivery has long been pursued but yet succeeded due to no such technologies for large biomacromolecules. We find a tertiary amine oxide-based polyzwitterion, OPDMA, that can efficiently penetrate both the stratum corneum (SC) and viable epidermis into circulation. So its conjugate with insulin, OPDMA-I, applied on the skin can exhibit hypoglycemic effects as efficiently as subcutaneously injected insulin in type-1 diabetic mice and minipigs. The unique pH-dependent cationic-to-zwitterionic transition of OPDMA in the characteristic acidic-to-neutral pH gradient from the skin surface to deep SC enables fast transdermal delivery of OPDMA and its conjugate. On the skin, OPDMA binds to carboxylic acids in the acidic sebum layer, enriching OPDMA-I on the SC. As pH increases in deeper SC layers, binding between OPDMA-I and the skin weakens gradually, allowing for diffusion through inter-corneocyte gaps and penetration into viable epidermis and finally entering the systemic circulation via dermal lymphatic vessels. This process does not alter SC microstructures or cause any physiological changes in the skin. This study represents a groundbreaking example of noninvasive transdermal protein delivery.

bioengineering↗

bioRxiv2023

Distributable, Metabolic PET Reporting of Tuberculosis

Tuberculosis remains a large global disease burden for which treatment regimens are protracted and monitoring of disease activity difficult. Existing detection methods rely almost exclusively on bacterial culture from sputum which limits sampling to organisms on the pulmonary surface. Advances in monitoring tuberculous lesions have utilized the common glucoside [18F]FDG, yet lack specificity to the causative pathogen Mycobacterium tuberculosis (Mtb) and so do not directly correlate with pathogen viability. Here we show that a close mimic that is also positron-emitting of the non-mammalian Mtb disaccharide trehalose - 2-[18F]fluoro-2-deoxytrehalose ([18F]FDT) - can act as a mechanism-based enzyme reporter in vivo. Use of [18F]FDT in the imaging of Mtb in diverse models of disease, including non-human primates, successfully co-opts Mtb-specific processing of trehalose to allow the specific imaging of TB-associated lesions and to monitor the effects of treatment. A pyrogen-free, direct enzyme-catalyzed process for its radiochemical synthesis allows the ready production of [18F]FDT from the most globally-abundant organic 18F-containing molecule, [18F]FDG. The full, pre-clinical validation of both production method and [18F]FDT now creates a new, bacterium-specific, clinical diagnostic candidate. We anticipate that this distributable technology to generate clinical-grade [18F]FDT directly from the widely-available clinical reagent [18F]FDG, without need for either bespoke radioisotope generation or specialist chemical methods and/or facilities, could now usher in global, democratized access to a TB-specific PET tracer.

biochemistry↗

bioRxiv2023

Convergence of resistance and evolutionary responses in Escherichia coli and Salmonella enterica co-inhabiting chicken farms in China

Sharing among different pathogens and commensals inhabiting same hosts and environments has significant implications for antimicrobial resistance (AMR), especially in settings with high antimicrobial exposure. We analysed 661 E. coli and S. enterica isolates collected within and across hosts and environments, in 10 Chinese chicken farms over 2.5 years using novel data-mining methods. Most isolates within same hosts possessed same clinically relevant AMR-carrying mobile genetic elements (plasmids: 70.6%, transposons: 78%), which also showed recent common evolution. Machine learning revealed known and novel AMR-associated mutations and genes underlying resistance to 28 antimicrobials and primarily associated with resistance in Escherichia coli and susceptibility in Salmonella enterica. Many of these genes were essential and affected same metabolic processes in both species, albeit with varying degrees of phylogenetic penetration. Multi-modal strategies are crucial to investigate the interplay of mobilome, resistance and metabolism in cohabiting bacteria, especially in ecological settings where community-driven resistance selection occurs.

genomics↗

bioRxiv2023

Artificial intelligence-driven morphology-based enrichment of malignant cells from body fluid

Cell morphology is a fundamental feature used to evaluate patient specimens in pathological analysis. However, traditional cytopathology analysis of patient effusion samples is limited by low tumor cell abundance coupled with high background of non-malignant cells, restricting the ability for downstream molecular and functional analyses to identify actionable therapeutic targets. We applied the Deepcell platform that combines microfluidic sorting, brightfield imaging, and real-time deep learning interpretations based on multi-dimensional morphology to enrich carcinoma cells from malignant effusions without cell staining or labels. Carcinoma cell enrichment was validated with whole genome sequencing and targeted mutation analysis, which showed higher sensitivity for detection of tumor fractions and critical somatic variant mutations that were initially at low-levels or undetectable in pre-sort patient samples. Combined, our study demonstrates the feasibility and added value of supplementing traditional morphology-based cytology with deep learning, multi-dimensional morphology analysis, and microfluidic sorting.

pathology↗

bioRxiv2022

lincRNA RP24-315D19.10 promotes endometrialdecidualization via upregulation of hnRNPA2B1

Sufficient decidualization is necessary to maintain successful pregnancy. The physiological function and underlying molecular mechanisms of intergenic long non-coding RNA (lincRNAs) in this process remain largely unknown. Herein, we identified a lincRNA, RP24-315D19.10, which is highly expressed during mouse decidualization during early pregnancy, by performing RNA-sequencing (RNA-seq) analysis and weighted gene co-expression network analysis (WGCNA). Detailed cell and molecular assays revealed that lincRNA RP24-315D19.10 knockdown blocked decidualization in primary mouse endometrial stromal cells (mESCs), suggesting that RP24-315D19.10 is a promoting factor for decidualization. Mechanistically, cytoplasmic RP24-315D19.10 directly interacted with heterogeneous nuclear ribonucleoprotein A2B1 (hnRNPA2B1) and upregulated its protein level. Moreover, we found that hnRNPA2B1 is involved in the regulation of decidualization through loss- and gain-of-function studies in vitro. Clinically, patients diagnosed with spontaneous miscarriage were found to have lower hnRNPA2B1 levels than healthy individuals, suggesting that RP24-315D19.10-regulated hnRNPA2B1 may participate in the development and progression of early spontaneous abortion. Our study indicates that RP24-315D19.10 enhances endometrial decidualization in a hnRNPA2B1-dependent manner, providing further insights into this physiological process.

molecular biology↗

bioRxiv2022

Sirt3 enhanced Bufalin sensitivity of colorectal cancer cells through P53-dependent pathway of apoptosis Sirt3 enhanced Bufalin sensitivity of colorectal cancer cells through P53-dependent pathway of apoptosis

Sirt3, one of class III histone deacetylase, is mainly localized in mitochondria and plays a significant role in the control of the metabolic activity, senescence and death [1]. Recently, Sirt3 emerged as a novel member of anticancer. However, the role of Sirt3 in colorectal cancer (CRC) has never been explained exactly. In this study, we found that sirt3 is down-regulated after Bufalin treatment. We also found that AC-P53 is up-regulated which induces Bax translocation to mitochondrion and open the mitochondrial permeability transition (mPTP) pores result in the release of cytochrome C lead to the activation of caspase-dependent apoptosis pathway. Collectively, our data suggests that Sirt3 may play an important role in CRC development and progression and may be a promising therapeutic target for CRC.

cancer biology↗

bioRxiv2022

Structure-Preserving and Batch-Correcting Visualization Using Deep Manifold Transformation for Single-cell RNA-Seq Profiles

Dimensionality reduction and visualization play an important role in biological data analysis, such as data interpretation of single-cell RNA sequence (scRNA-seq). It is desired to have a visualization method that can not only be applicable to various application scenarios, including cell clustering and trajectory inference, but also satisfy a variety of technical requirements, especially the ability to preserve inherent structure of data and handle with batch effects. However, no existing methods can accommodate these requirements in a unified framework. In this paper, we propose a general visualization method, deep visualization (DV), that possesses the ability to preserve inherent structure of data and handle batch effects and is applicable to a variety of datasets from different application domains and dataset scales. The method embeds a given dataset into a 2- or 3-dimensional visualization space, with either a Euclidean or hyperbolic metric depending on a specified task type with type static (at a time point) or dynamic (at a sequence of time points) scRNA-seq data, respectively. Specifically, DV learns a structure graph to describe the relationships between data samples, transforms the data into visualization space while preserving the geometric structure of the data and correcting batch effects in an end-to-end manner. The experimental results on nine datasets in complex tissue from human patients or animal development demonstrate the competitiveness of DV in discovering complex cellular relations, uncovering temporal trajectories, and addressing complex batch factors. We also provide a preliminary attempt to pre-train a DV model for visualization of new incoming data.

bioinformatics↗

bioRxiv2022

An allosteric agonist activates BK channels by perturbing coupling between Ca2+ binding and pore opening

BK type Ca2+-activated K+ channels activate in response to both the membrane voltage and intracellular Ca2+ with distinct mechanisms. Ca2+ binds to the cytosolic domain (CTD) to open the pore across the membrane, but the mechanism that couples Ca2+ binding to pore opening is not clear. Here we show that a compound, BC5, identified using in silico screening, interacts with BK channels at the interface between the CTD and the transmembrane voltage sensing domain (VSD) and enhances channel activity by specifically affecting the Ca2+ dependent mechanism. BC5 activates the channel in the absence of Ca2+ binding but Ca2+ binding inhibits BC5 effects. Thus, BC5 perturbs the pathway that couples Ca2+ binding to pore opening to allosterically affect both, which is supported by atomistic simulations and mutagensis. The results suggest that the CTD- VSD interaction makes a major contribution to the mechanism of Ca2+ dependent activation and is an important site for allosteric agonists to modulate BK channel activation.

biophysics↗

bioRxiv2021

A spatial stochastic model reveals the role of supercoiling in transcription regulation

In Escherichia coli, translocation of RNA polymerase (RNAP) during transcription introduces supercoiling to DNA, which influences the initiation and elongation behaviors of RNAP. To quantify the role of supercoiling in transcription regulation, we develop a spatially resolved supercoiling model of transcription, describing RNAP-supercoiling interactions, topoisomerase activities, stochastic topological domain formation, and supercoiling diffusion in all transcription stages. This model establishes that transcription-induced supercoiling mediates the cooperation of co-transcribing RNAP molecules in highly expressed genes. It reveals that supercoiling transmits RNAP-accessible information through DNA and enables different RNAP molecules to communicate within and between genes. It thus predicts that a topological domain could serve as a transcription regulator, generating substantial transcription bursting and coordinating communications between adjacent genes in the domain. The model provides a quantitative platform for further theoretical and experimental investigations of how genome organization impacts transcription. Author SummaryDNA mechanics and transcription dynamics are intimately coupled. During transcription, the translocation of RNA polymerase overwinds the DNA ahead and underwinds the DNA behind, rendering the DNA supercoiled. The supercoiled DNA could, in return, influences the behavior of the RNA polymerase, and consequently the amount of mRNA product it makes. Furthermore, supercoils could propagate on the DNA over thousands of base pairs, impacting RNA polymerase molecules at faraway sites. These complicated interplays between supercoiling and RNA polymerase makes supercoiling an important transcription regulator. To quantitatively investigate the role of supercoiling in transcription, we build a spatially resolved model that links transcription with the generation, propagation, and dissipation of supercoiling. Our model reveals that supercoiling mediates transcription at multiple length scales. At a single-gene scale, we show that supercoiling gives rise to the collective motion of co-transcribing RNA polymerase molecules, supporting recent experimental observations. Additionally, large variations in mRNA production of a gene can arise from the constraints of supercoiling diffusion in a topological domain. At a multi-gene scale, we show that supercoiling dynamics allow two adjacent genes influence each others transcription kinetics, thus serving as a transcription regulator.

biophysics↗

bioRxiv2021

An ensemble of toxic channel types underlies the severity of the de novo variant G375R of the human BK channel

The molecular basis of a severe developmental and neurological disorder associated with a de novo G375R variant of the tetrameric BK channel is unknown. Here we address this question by recording from single BK channels expressed for a heterozygous G375R mutation. Five different types of functional BK channels were observed: 3% were WT, 12% were homomeric mutant, and 85% were three different types of hybrid channels. All channel types except WT showed a marked gain-of-function in voltage activation and a smaller loss-of-function in single channel conductance, with both becoming more pronounced as the number of mutant subunits per tetrameric channel increased. The molecular phenotype suggested codominance for the two homomeric channels and partial dominance for the hybrid channels. A model in which BK channels are randomly assembled from mutant and WT subunits, with each subunit contributing increments of activation and conductance, approximated the molecular phenotype of the heterozygous G375R mutation.

neuroscience↗