Biology subjects

Luo, F.

Publications and source records attributed to Luo, F..

At least 19 recordsLinked to original sources

bioRxiv2026

Glioblastoma Hijacks Astrocyte Ribosomes to Feul Malignancy through Translatome Reprogramming

Cancer cells demand elevated protein synthesis, yet whether they directly requisition ribosomes from microenvironmental host cells remains unknown. Here, utilizing in vivo and in vitro ribosome tracing, we show that glioblastoma (GBM) cells hijack ribosomes from surrounding astrocytes via tunneling nanotube-like structures. This transfer supports GBM malignancy in both murine and patient derived models. Single cell RNA sequencing along with whole cell and cell source traceable ribosome profiling reveal that transferred ribosomes are translationally active and selectively reprogram the tumor translatome, prioritizing cell-cycle genes and driving interferon-response-mediated immune evasion. Through a genome wide CRISPR screen, we identify INTS12 as a critical mediator of ribosome transfer. Genetic inactivation or AAV-mediated knockdown of INTS12 impairs ribosome uptake, curbs translation and proliferation, remodels the immunosuppressive landscape, and extends survival in orthotopic models. Our study uncovers a parasitic translation-support mechanism in GBM, establishing INTS12 as a therapeutic vulnerability to disrupt ribosome transfer.

cancer biology↗

bioRxiv2026

Efferocytosis Remodels Osteoclast Metabolism and Enhances Antibacterial Defense

Osteoclasts are metabolically specialized for bone resorption, but how apoptotic-cell uptake shapes their immune function remains unclear. During Staphylococcus aureus bone infection, osteoclasts engulfed apoptotic neutrophils. In osteoclast cultures, apoptotic-neutrophil exposure reduced multinucleation and resorption, induced host-defense programs, and enhanced antibacterial activity, whereas macrophages showed no comparable antibacterial response. MERTK was required for efficient osteoclast efferocytosis. Ctsk-Cre-mediated Mertk deletion increased bacterial burden and bone loss, whereas transplantation of MERTK-competent bone marrow restored osteoclast efferocytosis and reduced infection-associated bone damage. Transcriptomic and extracellular flux analyses revealed enhanced glycolytic activity and altered lactate handling in efferocytic osteoclasts. Lactate supplementation reduced osteoclast formation without reproducing the antibacterial phenotype. Inhibiting lactate production or export attenuated antibacterial activity in efferocytic osteoclasts, whereas blocking lactate uptake enhanced it. These findings identify osteoclast efferocytosis as an immune adaptation that links apoptotic-neutrophil clearance to metabolic remodeling and antibacterial defense in bone.

cell biology↗

bioRxiv2026

Constructing Virtual Viruses in A Spatial Minimal Cell

Viral development links gene expression and genome replication to particle formation within a cell. Here we construct virtual viruses in a JCVI-syn3A-based spatial minimal cell. For mycoplasma virus P1, molecular events connect expression and replication to coarse-grained packaging, followed by a spatial reconstruction of membrane opening and particle release. Individual finite-size particles coexist, move across the boundary and undergo partial crossings and returns before complete exit. In contrast, Acholeplasma phage MV-L1 (L1) expresses its genes and accumulates genomes as the host continues to grow and develops a constricted shape. The coexistence of viral activity and continued host growth is qualitatively consistent with the non-lytic biology of group 1 acholeplasmaviruses. These reconstructions extend the virtual cell to the viruses that develop within it, linking molecular activity, particle behavior and host growth.

synthetic biology↗

bioRxiv2026

The secreted elastase SjCE2b drives host skin penetration by Schistosoma japonicum

Cercarial elastase is the most abundant protease secreted by Schistosoma mansoni and plays a critical role in cercarial invasion. Although Schistosoma japonicum encodes only a single elastase, SjCE2b, its secretion by cercariae and its specific function in skin penetration have remained elusive. Here, we report the first proteomic analysis of S. japonicum cercarial excretory-secretory products (ESPs) induced by linoleic acid or mouse skin, confirming the presence of SjCE2b in both ESPs preparations. Recombinant SjCE2b expressed in Pichia pastoris was characterized as a trypsin-like serine protease whose activity is entirely abolished by the elastase inhibitor MeoSuc-AAPF-CMK. Furthermore, SjCE2b expression was detected exclusively in cercarial extracts and localized specifically to the cercarial acetabular glands and ducts. Subsequent proteomic analysis indicates that SjCE2b can degrade numerous human epidermal proteins, including ten isoforms of type I and type II keratins. In vitro digestion assays further demonstrated that SjCE2b can digest key structural components of the dermis, including elastin, collogen, and fibronectin. Additionally, the cleavage of complement component C3 and immunoglobulins (IgA and IgG) suggests that SjCE2b may facilitate immune evasion by newly transformed schistosomula. Critically, the incubation of cercariae with anti-rSjCE2b antibody reduced the worm burden by 80.85%, confirming the essential role of SjCE2b in the skin penetration of S. japonicum cercariae and highlighting it as a compelling candidate for vaccine or therapeutic development. Author SummarySchistosomiasis constitutes a major global health burden caused by parasitic flatworms of the genus Schistosoma. Proteolytic and histolytic enzymes secreted by cercarial pre- and post-acetabular glands facilitate disruption of the host skin barrier and protect the parasite from localized dermal inflammatory response. Although cercarial elastase is a well-characterized invasion enzyme in Schistosoma mansoni, its role in Schistosoma japonicum remains poorly defined; consequently, S. japonicum cercariae have been hypothesized to rely on distinct repertoire of proteolytic enzymes during skin penetration. In the present study, we showed that SjCE2b was localized to the cercarial acetabular glands and ducts, and was secreted upon stimulation with linoleic acid or mouse skin. Functionally, SjCE2b can disrupt host skin integrity by degrading epidermal and dermal components, and may promote immune evasion through cleavage of complement component and immunoglobins. Furthermore, the antibody-mediated neutralization of secreted SjCE2b significantly impaired parasite penetration by greater than 80%. Together, these findings establish SjCE2b as a critical enzyme required for S. japonicum cercariae invasion and highlight its potential as a promising target for novel therapeutic interventions.

microbiology↗

bioRxiv2026

Dual Control of LDL-cholesterol Levels by ANGPTL3 and ANGPTL8

BACKGROUNDInactivation of ANGPTL3 (angiopoietin-like protein 3, A3) is a proven therapeutic strategy for lowering plasma lipid levels independently of the LDL receptor (LDLR), yet the optimal approach to inactivate A3 remains unclear. A3 is proteolytically cleaved and circulates as full-length (A3-FL), N-terminal (A3-Nter) and C-terminal (A3-Cter) fragments. The specific contribution of each form of A3, and of its paralog, ANGPTL8 (A8), in modulating circulating levels of ApoB-Containing Lipoproteins (ABCLs) remain poorly defined. Clarifying these relationships will inform next-generation A3-directed therapies. METHODSWe performed liver perfusion studies to directly compare the number and composition of VLDL particles secreted from mice with and without A3. To amplify effects on cholesterol metabolism, we generated Ldlr-/- mice expressing wildtype A3 (A3-WT), A3-FL or A3-Nter, with or without co-expression of A8, and analyzed plasma lipids, circulating A3 and A8 complexes, and intravascular lipase activities. Complementary in vitro assays and structural modeling were used to assess relative endothelial lipase (EL) inhibition by A3 alone or in complex with A8. RESULTSLiver perfusion studies revealed that A3 inactivation does not alter the rates of hepatic secretion of VLDL in wildtype or Ldlr-/- mice. Inactivation of A8 alone lowered plasma LDL-cholesterol (C) levels by [~]20%, an effect dependent upon the expression of both EL and A3. Maximal inhibition of lipoprotein lipase (LPL) required co-expression of A8 plus both A3-FL and A3-Nter, indicating that A3 cleavage, in addition to A8 expression, is essential for maximal LPL inhibition. In contrast, A8 expression, but not A3 cleavage, was required for optimal EL inhibition. CONCLUSIONSA8 acts in concert with A3 to differentially modulate LPL- and EL-mediated lipolysis, which antagonizes hepatic clearance of newly-secreted atherogenic ABCLs. This mechanistic framework refines our understanding of A3-targeted lipid lowering and highlights the therapeutic potential of dual A3- plus A8-directed strategies to treat dyslipidemia and prevent atherosclerotic cardiovascular disease. Clinical perspectiveO_ST_ABSWhat is new?C_ST_ABSO_LIInactivation of A3 lowers circulating ABCL levels without altering hepatic secretion rates of VLDL-ApoB or -TG. C_LIO_LIProteolytic cleavage of A3 is required for maximal inhibition of LPL. C_LIO_LIInactivation of A8 lowers LDL-C levels through an A3- and EL-dependent, but LDLR-independent, mechanism. C_LI What are the clinical implications?O_LICombining A8 inhibition with A3-inactivating therapies offers a strategy to achieve greater reduction in LDL-C levels and atherosclerotic cardiovascular risk. C_LI

molecular biology↗

bioRxiv2026

Fully genetically encoded low-molecular-weight protein tags with defined shapes for direct molecular identification by cryo-electron tomography

Cryo-electron tomography (cryo-ET) enables three-dimensional visualization of cells in near-native states, but direct identification of specific proteins in situ remains challenging due to crowded cellular environments and the low intrinsic contrast of most proteins smaller than [~]500 kDa. Consequently, molecular identification often relies on indirect labeling strategies or bulky probes that can perturb native structures. Here we present a "shape-as-signal" strategy that uses fully genetically encoded protein tags with defined shapes as a molecular signal for direct identification by cryo-ET. We designed two single-chain, monomeric, low-molecular-weight tags: an extended V-shaped tag (62 kDa) and a compact triangular tag (85 kDa). Both adopt rigid geometries validated by cryo-electron microscopy and remain compatible with fluorescence microscopy when fused to fluorescent proteins. Their characteristic shapes are readily recognized and computationally detected in vitro. In cells, the V-shaped tag yields clear, non-disruptive signals at native locations. These results demonstrate that low-molecular-weight protein tags can be unambiguously detected and assigned in situ within crowded cellular environments. This single-step genetic tagging strategy enables seamless dual fluorescence and electron microscopy without exogenous probes, challenging the assumption that small protein tags are unsuitable for direct cryo-ET identification. More broadly, this approach establishes a scalable and minimally perturbative framework for visual proteomics and paves the way for multiplexed, shape-encoded molecular mapping in intact cells.

biophysics↗

bioRxiv2025

Synchronized Latency Reversal and Immune Clearance by a Multifunctional Fusion Protein Enables HIV-1 Reservoir Reduction

Strategies that concurrently reactivate latent reservoirs and enhance immune-mediated clearance hold significant promise for achieving an HIV cure. Here, we developed hyperIL-15xsCD4-Fc (15xsCD4-Fc), a fusion protein that integrates latency reactivation, targeted immune engagement, and effector-mediated killing into a single molecule. This agent not only potently reverses HIV-1 latency in CD4+ T cells from people living with HIV-1 (PLWH) through coordinated IL-15 receptor signaling and sCD4-mediated HIV-1 envelope (Env) engagement, but also enhances antigen-specific CD8+ T cell response in PBMCs derived from PLWH. Furthermore, 15xsCD4-Fc enables Env-specific elimination of reactivated latently infected cells by NK cells while preventing off-target cytotoxicity. In PBMCs from PLWH, 15xsCD4-Fc reduced replication-competent HIV-1 DNA by 93.8%. In antiretroviral treated HIV-1-infected humanized mice, the molecule demonstrated both safety and efficacy in diminishing viral reservoir in lymphoid organs. This spatiotemporally coupled approach to reservoir exposure and immune recognition establishes a clinically viable strategy for clearing the HIV-1 reservoir. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=195 SRC="FIGDIR/small/693434v1_ufig1.gif" ALT="Figure 1"> View larger version (44K): org.highwire.dtl.DTLVardef@8f8f0org.highwire.dtl.DTLVardef@10f63f7org.highwire.dtl.DTLVardef@16c1de2org.highwire.dtl.DTLVardef@11e1787_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2025

Unimeth: A unified transformer framework for accurate DNA methylation detection from nanopore reads

Nanopore sequencing enables direct detection of DNA modifications from native DNA. However, accurate methylation calling across species, sequence contexts, modification types and chemistries remains challenging. We present Unimeth, a transformer-based framework that jointly processes raw signals and basecalled sequences in read patches and predicts all target methylation sites within each patch. Unimeth uses a three-phase training strategy that combines signal pre-training, methylation fine-tuning and site-level calibration using methylation frequency information. We evaluated Unimeth for 5mC and 6mA detection using public and in-house datasets spanning 14 species, three nanopore chemistries and wild-type, mutant and enzyme-treated samples. Unimeth improved plant 5mC detection in non-CpG contexts, reduced false-positive calls in low-methylation samples and maintained high 5mCpG performance in mammalian datasets. For 6mA, Unimeth reduced background calls while preserving signals for Fiber-seq nucleosome and gene-level analyses. Unimeth provides a unified framework for nanopore-based methylation detection across methylation types and biological contexts.

bioinformatics↗

bioRxiv2025

CARP Protects Against Doxorubicin-induced Cardiotoxicity through NRF1-driven Mitochondrial Homeostasis

AimsDoxorubicin (DOX), a highly effective anthracycline chemotherapeutic agent, is limited by its dose-dependent cardiotoxicity. This study investigates the cardioprotective mechanisms of cardiac adriamycin responsive protein (CARP) and its underlying mechanisms in DOX-induced cardiotoxicity (DIC). Methods and resultsCardiac-specific CARP transgenic and wild-type mice were subjected to a DIC model. Cardiac function was assessed via echocardiography, histopathology, and transmission electron microscopy (TEM). In vitro, DOX-treated cardiomyocytes overexpressing CARP were analyzed for oxidative stress (ROS levels), mitochondrial function (mtDNA copy number etc.), and mitochondrial-related proteins (Western blot). CARP-NRF1 interaction was validated by co-immunoprecipitation (Co-IP), and NRF1 siRNA knockdown was performed to assess CARPs role in mitochondrial homeostasis. CARP overexpression markedly alleviated DOX-induced cardiac dysfunction and mitochondrial damage, restoring mitochondrial dynamics and mitophagy. Mechanistically, CARP directly interacted with NRF1, and NRF1 knockdown ameliorated CARP-mediated cardioprotection in DIC. ConclusionCARP safeguards against DIC by maintaining mitochondrial homeostasis via NRF1 signaling, positioning it as a promising therapeutic target for DOX-induced cardiomyopathy.

molecular biology↗

bioRxiv2025

Delivery of collagen-encoding mRNA to the skin for cosmetic applications

Collagens, the predominant structural proteins in mammalian, maintain tissue integrity through its unique triple-helical conformation. Traditionally, cosmetic collagens have been administered as hydrolyzed peptides derived from animal sources, which exhibit poor bioavailability and functional efficacy due to limited skin penetration and disrupted tertiary/quaternary structures. To overcome these limitations, we developed a novel system for in vivo collagen expression. This system utilizes the topical application of in vitro synthesized, AI-designed mRNAs encoding types I, III, and XVII collagens to improve human skin condition. Significant upregulation of target collagen expression was observed in dermal fibroblasts, leading to improved skin condition through in situ assembly of collagens in natural conformation.

bioengineering↗

bioRxiv2025

Compact Tape-Driven Sample Delivery System for Serial Femtosecond Crystallography

We developed a compact tape-drive with on-demand sample delivery (CoT) for time-resolved serial femtosecond crystallography (SFX) experiments that can deliver sample droplets and/or initiate reactions with a drop-on-drop strategy. Two disposable piezoelectric injectors are positioned in tandem along the tape to produce a queue of nanoliter-scale droplets. X-ray free-electron laser (XFEL) pulses arrive perpendicular to and pass through the broad face of the tape where the pulse is synchronized and aligned to the droplets and thereby enables very highly efficient SFX data collection. The tape transport speed and the delivery distance can be varied to control the mixing time from approximately 130 ms to tens of seconds. We conducted time-resolved SFX experiments utilizing a basic enzymatic reaction model of hen egg white lysozyme (HEWL) and N-acetyl-D-glucosamine (GlcNAc) to demonstrate the drop-on-drop capabilities of CoT, and the full binding process of GlcNAc to HEWL was observed at 1.3-9.7 s. SynopsisTape-driven liquid sample droplet delivery system for serial femtosecond crystallography

biophysics↗

bioRxiv2024

The RING-finger domain of Arabidopsis RMR functions as an E3 ligase essential for post-Golgi trafficking

Receptor-homology-transmembrane-RING-H2 (RMR) sorting receptors are essential for directing soluble cargo proteins to protein storage vacuoles in plants. These type I integral membrane proteins comprise a single transmembrane domain, an N-terminal lumenal region containing a protease-associated domain for cargo recognition, and a C-terminal cytoplasmic region (CT) with a Really-Interesting-New-Gene-H2 (RING-H2) domain. Here, we determined the crystal structure of the RING-H2 domain of Arabidopsis RMR isoform-1 (AtRMR1-RING), where the conserved C3H2C3 motif coordinates two Zn ions, a feature typical of RING-type E3 ligases. AtRMR1-RING was shown to interact with Arabidopsis E2 ubiquitin-conjugating enzyme, and exhibits E3 ligase activity in an in vitro ubiquitination assay. Biochemical analysis reveals that I234Y substitution disrupted the E2/E3 interaction and greatly reduced E3 ligase activity. Furthermore, we showed that the conserved RING-H2 domains of AtRMR isoform 2, 3 and 4 are also E3 ligases. Inactivation of E3 ligase activity by the I234Y mutation resulted in Golgi retention of AtRMR1-CT and AtRMR2. These findings suggest that the E3 ligase activity is essential for post-Golgi trafficking of RMR receptors, providing new insights into receptor-mediated protein sorting in plants.

plant biology↗

bioRxiv2024

Identification of a Cluster of Benzene Activation Enzymes in a Strictly Anoxic Methanogenic Consortium

The Oil Refinery (OR) consortium is a model methanogenic enrichment culture used to study anaerobic benzene degradation. Over half of the cultures bacterial community consists of two closely related Desulfobacterota strains, designated ORM2a and ORM2b, whose mechanisms of benzene activation are unknown. Two new metagenomes, including a complete circularized metagenome-assembled genome (MAG) for ORM2a, enabled a thorough investigation of this cultures proteome. Among the proteins identified were Bam-like subunits of an ATP-independent benzoyl-CoA degradation pathway, as well as downstream {beta}-oxidation proteins yielding acetate. The most abundant proteins identified mapped to two ORM2a gene clusters of unknown function. Homologous and syntenic gene clusters were identified in genomes of ORM2b and a sulfate-reducing Pelotomaculum that also degrades benzene, as well as in nine contigs assembled from hydrothermal vent metagenomes. Extensive homology and structural predictions suggest that the first cluster - termed the "Magic" gene cluster - encodes for enzymes catalyzing the chemically challenging activation of benzene and subsequent transformation steps yielding benzoyl-CoA. The second ("Nanopod") gene cluster encodes a transmembrane complex that may facilitate benzene transport across the cell membrane. Phylogenomic analyses place ORM2a and ORM2b within a novel genus of strict anaerobes specialized for benzene degradation, which we propose naming "Candidatus Anaerobenzenivorax". IMPORTANCEBenzene is a widespread, persistent and toxic pollutant that can accumulate in anoxic environments such as groundwater and sediments. Despite decades of study, the biochemical mechanisms by which benzene is activated under anaerobic conditions remain unproven. This study provides strong genetic and proteomic evidence for a new class of enzymes that initiate anaerobic benzene activation and proposes a preliminary model for their underlying biochemistry. These findings lay a foundation for future biochemical studies and expand our understanding of how microbes carry out extreme redox chemistry in the absence of oxygen.

microbiology↗

bioRxiv2024

Integrated temporal profiling of iPSCs-derived motor neurons from ALS patients carrying C9orf72, FUS, TARDBP, and SOD1 mutations

Amyotrophic Lateral Sclerosis (ALS) is a lethal neurodegenerative disease that damages motor neurons in the central nervous system, causing progressive muscle weakness that ultimately leads to death. However, its underlying mechanisms still need to be fully understood, particularly the heterogeneity and similarity between various gene mutants during disease progression. In this study, we conducted temporal RNA-seq profiling in human induced pluripotent stem cells (hiPSCs) and iPSC-derived motor neurons (iMNs) carrying the C9orf72, FUS, TARDBP, and SOD1 mutations from both ALS patients and healthy individuals. We discovered dysregulated gene expression and alternative splicing (AS) throughout iMN development and maturation, and ALS iMNs display enrichment of cytoskeletal defects and synaptic alterations from premature stage to mature iMNs. Our findings indicate that synaptic gene dysfunction is the common molecular hallmark of fALS, which might result in neuronal susceptibility and progressive motor neuron degeneration. Analysis of upstream splicing factors revealed that differentially expressed RNA-binding proteins (RBPs) in ALS iMNs may cause abnormal AS events, suggesting the importance of studying RBP defects in ALS research. Overall, our research provides a comprehensive and valuable resource for gaining insights into the shared mechanisms of ALS pathogenesis during motor neuron development and maturation in iMN models.

neuroscience↗

bioRxiv2024

A brainstem circuit controls cough-like airway defensive behaviors in mice

The respiratory tract is subject to complex neural control for eupneic breathing and distinct airway defensive reflexes. Growing evidence has highlighted significant heterogeneity of airway-innervating vagal sensory neurons in mediating various respiratory functions, however, the central neuronal pathways and neural circuits involved in the airway regulation remain less understood. Combining whole-body plethysmography (WBP), audio, and video tracking to access breathing and airway defensive behaviors in conscious animals, we developed a quantitative paradigm implementing the mouse as a model to study cough-like defensive behaviors. Using TRAP2 transgenic mice and in vivo fiber photometry, we found that the neural activity in the caudal spinal trigeminal nucleus (SP5C) is strongly correlated with tussigen-evoked cough-like responses. Impairing synaptic outputs or chemogenetic inhibition of the SP5C effectively abolished these cough-like reflexes. Optogenetic stimulation of SP5C excitatory neurons or their projections to the ventral respiratory group (VRG) triggered robust cough-like behaviors without tussive stimuli. Notably, tonic elevation of SP5C excitability caused spontaneous cough-like activities chronically in mice. Together, our data provide strong evidence for a previously unrecognized brainstem circuit that controls cough-like defensive behaviors in mice.

neuroscience↗

bioRxiv2024

Dorsolateral septum GLP-1R neurons regulate feeding via lateral hypothalamic projections

ObjectiveAlthough glucagon-like peptide 1 (GLP-1) is known to regulate feeding, the central mechanisms contributing to this function remain enigmatic. Here, we aim to test the role of neurons expressing GLP-1 receptors (GLP-1R) in the dorsolateral septum (dLS; dLSGLP-1R) and their downstream projections on food intake and determine the relationship with feeding regulation. MethodsUsing chemogenetic manipulations, we assessed how activation or inhibition of dLSGLP-1R neurons affected food intake in Glp1r-ires-Cre mice. Then, we used channelrhodopsin-assisted circuit mapping, chemogenetics, and electrophysiological recordings to identify and assess the role of the pathway from dLSGLP-1R neurons to the lateral hypothalamic area (LHA) in regulating food intake. ResultsChemogenetic inhibition of dLSGLP-1R neurons increases food intake. LHA is a major downstream target of dLSGLP-1R neurons. The dLSGLP-1R[->]LHA projections are GABAergic, and chemogenetic inhibition of this pathway also promotes food intake. While chemogenetic activation of dLSGLP-1R[->]LHA projections modestly decreases food intake, optogenetic stimulation of the dLSGLP-1R[->]LHA projection terminals in the LHA rapidly suppressed feeding behavior. Finally, we demonstrate that the GLP-1R agonist, Exendin 4 enhances dLSGLP-1R [->]LHA GABA release. ConclusionsTogether, these results demonstrate that dLS-GLP-1R neurons and the inhibitory pathway to LHA can regulate feeding behavior, which might serve as a potential therapeutic target for the treatment of eating disorders or obesity. HighlightsO_LIChemogenetic inhibition of dLSGLP-1R neurons boosts food intake in mice C_LIO_LIdLSGLP-1R neuron activation does not alter feeding, likely by collateral inhibition C_LIO_LIdLSGLP-1R neurons project to LHA and release GABA C_LIO_LIActivation of dLSGLP-1R [->]LHA axonal terminals suppresses food intake C_LIO_LIGLP-1R agonism enhances dLSGLP-1R [->]LHA GABA release via a presynaptic mechanism C_LI

neuroscience↗

bioRxiv2023

Neurexins control the strength and precise timing of glycinergic inhibition in the auditory brainstem

Neurexins play diverse functions as presynaptic organizers in various glutamatergic and GABAergic synapses. However, it remains unknown whether and how neurexins are involved in shaping functional properties of the glycinergic synapses, which mediate prominent inhibition in the brainstem and spinal cord. To address these issues, we examined the role of neurexins in a model glycinergic synapse between the principal neuron in the medial nucleus of the trapezoid body (MNTB) and the principal neuron in the lateral superior olive (LSO) in the auditory brainstem. Combining RNAscope with stereotactic injection of AAV-Cre in the MNTB of neurexin1/2/3 conditional triple knockout mice, we showed that MNTB neurons highly express all isoforms of neurexins although their expression levels vary remarkably. Selective ablation of all neurexins in MNTB neurons not only reduced the amplitude but also altered the kinetics of the glycinergic synaptic transmission at LSO neurons. The synaptic dysfunctions primarily resulted from an impaired Ca2+ sensitivity of release and a loosened coupling between voltage-gated Ca2+ channels and synaptic vesicles. Together, our current findings demonstrate that neurexins are essential in controlling the strength and temporal precision of the glycinergic synapse, which therefore corroborates the role of neurexins as key presynaptic organizers in all major types of fast chemical synapses.

neuroscience↗

bioRxiv2023

Suberoylanilide Hydroxamic Acid Attenuates Cognitive Impairment in Offspring Caused by Maternal Surgery during Mid-pregnancy

It is known that commonly-used anesthetics can cause long-term neurotoxicity in the developing brain. Some pregnant women have to experience non-obstetric surgery during pregnancy under general anesthesia. It is known that maternal exposure to sevoflurane, isoflurane, propofol and ketamine causes cognitive deficits in offspring. Histone acetylation has been implicated in synaptic plasticity, and abnormal histone acetylation contributes to the neonatal sevoflurane exposure induced deficits in hippocampus-dependent learning and memory. The HDAC inhibitor suberoylanilide hydroxamic acid (SAHA) was shown to attenuate the sevoflurane-induced deficits. Propofol is commonly used in non-obstetric procedures on pregnant women. Recent evidence shows that propofol also causes neurotoxicity in developing brains. For example, previous studies in our laboratory showed that maternal propofol exposure in pregnancy impairs learning and memory in offspring by disturbing histone acetylation. The present study aims to investigate whether SAHA could also attenuate propofol-induced learning and memory deficits in offspring caused by maternal surgery during mid-pregnancy. Maternal rats were exposed to propofol or underwent abdominal surgery under propofol anesthesia during middle pregnancy. The learning and memory abilities of the offspring rats were assessed using Morris water maze (MWM) test. The protein levels of histone deacetylase 2 (HDAC2), phosphorylated cAMP response-element binding (p-CREB),brain derived neurotriphic factor (BDNF) and phosphorylated tyrosine kinase B (p-TrkB) in the hippocampus of the offspring rats were evaluated by immunofluorescence staining and western blot. Hippocampal neuroapoptosis was detected by TUNEL staining. Our results showed that maternal propofol exposure during middle pregnancy impaired the water-maze learning and memory of the offspring rats, increased the protein level of HDAC2 and reduced the protein levels of p-CREB,BDNF and p-TrkB in the hippocampus of the offspring, and such effects were exacerbated by surgery. SAHA alleviated the cognitive dysfunction and rescued the changes in the protein levels of p-CREB, BDNF and p-TrkB induced by maternal propofol exposure alone or maternal propofol exposure plus surgery. Therefore, SAHA could be a potential and promising agent for treating the learning and memory deficits in offspring caused by maternal nonobstetric surgery under propofol aneshtesia.

neuroscience↗