Biology subjects

Guan, X.

Publications and source records attributed to Guan, X..

At least 55 records · Page 3Linked to original sources

bioRxiv2023

Integration of eQTL and Machine Learning Methods to Dissect Causal Genes with Pleiotropic effects in Genetic Regulation Networks of Seed Cotton Yield

Expression quantitative trait loci (eQTL) provide a powerful means of investigating the biological basis of genome-wide association study (GWAS) results and exploring complex traits or phenotypes. In addition to identifying the causal gene in cis, eQTL analysis also reveals a large number of trans-regulated genes located on different chromosomes, which form a gene regulatory network (GRN) that complements the GWAS locus. However, the dissection of a GRN and the crosstalk underlying multiple agronomical traits, along with prioritizing important genes in eQTL-derived GRNs, remains a major challenge. In this study, we generated 558 transcriptional profiles of lint-bearing ovules at one day post-anthesis (DPA) from a selective core cotton germplasm, from which we identified 12,207 eQTLs. By integrating with a GWAS catalog, we found that 66 out of 187 (35.29%) known phenotypic GWAS loci are colocalized with 1,090 eQTLs, forming 38 major functional GRNs predominantly (30 out of 38) associated with seed size-related phenotypes. Of the eGenes, 34 were shared between at least two functional GRNs, exhibiting pleiotropic effects, such as NF-YB3, GRDP1, and IDD7. Narrow-sense heritability analysis showed that the heritability increased with combining the eQTLs with GRNs compared to those with previous yield trait GWAS loci. The extreme gradient boosting (XGBoost) machine learning approach was then applied to predict seed cotton yield phenotypes based on gene expression. Top-ranking eGenes (NF-YB3, FLA2, and GRDP1) derived by XGBoost with pleiotropic effects on yield traits were validated, along with their potential roles by correlation analysis, domestication selection analysis, and transgenic plants. This study provides insights into the mining of GRNs in relation to the pleiotropy of phenotype. The combination of eQTL and machine learning approaches is efficient in improving the genetic dissection of agricultural traits.

genetics↗

bioRxiv2023

Cell based dATP delivery as a therapy for chronic heart failure.

Withdrawal StatementThe authors have withdrawn this manuscript because the senior authors have identified inconsistencies in the data presented in this manuscript, which affect the reliability of the main conclusions. In keeping with our commitment to scientific rigor and transparency, the authors do not wish this work to be cited as reference for the project. If you have any questions, please contact the corresponding authors.

pathology↗

bioRxiv2023

Gas diffusion kinetics drive embolism spread in angiosperm xylem: evidence from flow-centrifuge experiments and modelling

Understanding xylem embolism formation is challenging due to dynamic changes and multiphase interactions in conduits. If embolism spread involves gas movement in xylem, we hypothesise that it is affected by time. We measured hydraulic conductivity (Kh) in flow-centrifuge experiments over one hour at a given pressure and temperature for stem samples of three angiosperm species. Temporal changes in Kh at 5, 22, and 35{degrees}C, and at various pressures were compared to modelled gas pressure changes in a recently embolised vessel in the centre of a centrifuge sample. Temporal changes in Kh at 22{degrees}C showed maximum relative increases between 6% and 40%, and maximum decreases between 41% and 61% at low and high centrifugal speed, respectively. Logarithmic changes in Kh were species-specific, and most pronounced during the first 15 minutes. Embolism formation started near the edges of centrifuge samples and gradually increased at the centre. Moreover, measured decreases in Kh strongly correlated with modelled increases in gas concentration in a recently embolised vessel. Although embolism is mostly pressure-driven, our experimental and modelled data indicate that time, conduit characteristics, and temperature are involved due to their role in gas diffusion. Gas diffusion, however, does not cover the entire process of embolism spread.

plant biology↗

bioRxiv2023

Supervised learning of high-confidence phenotypic subpopulations from single-cell data

Accurately identifying phenotype-relevant cell subsets from heterogeneous cell populations is crucial for delineating the underlying mechanisms driving biological or clinical phenotypes. Here, by deploying a learning with rejection strategy, we developed a novel supervised learning framework called PENCIL to identify subpopulations associated with categorical or continuous phenotypes from single-cell data. By embedding a feature selection function into this flexible framework, for the first time, we were able to select informative features and identify cell subpopulations simultaneously, which enables the accurate identification of phenotypic subpopulations otherwise missed by methods incapable of concurrent gene selection. Furthermore, the regression mode of PENCIL presents a novel ability for supervised phenotypic trajectory learning of subpopulations from single-cell data. We conducted comprehensive simulations to evaluate PENCILs versatility in simultaneous gene selection, subpopulation identification and phenotypic trajectory prediction. PENCIL is fast and scalable to analyze 1 million cells within 1 hour. Using the classification mode, PENCIL detected T-cell subpopulations associated with melanoma immunotherapy outcomes. Moreover, when applied to scRNA-seq of a mantle cell lymphoma patient with drug treatment across multiple time points, the regression mode of PENCIL revealed a transcriptional treatment response trajectory. Collectively, our work introduces a scalable and flexible infrastructure to accurately identify phenotype-associated subpopulations from single-cell data.

bioinformatics↗

bioRxiv2023

Re-evaluating the nuclear staining on pathological sections in Alzheimer's disease

A paper recently published on Nature Neuroscience, asserting that lysosome leakage induces neuronal cell death and the formation of senile plaques in Alzheimers disease. The study believed that flower-like perikaryal rosettes formed by packed autophagic vacuoles around central nuclei, termed "PANTHOS" neurons, are responsible for the senile plaque formation. However, all of the nuclei staining in this paper based on images in the blue fluorescence channel. We did detailed studies on the senile plaque blue autofluorescence and found that senile plaque blue autofluorescence could be easily mistaken as nuclear staining. The blue "nuclear" staining in this paper is probably inaccurate since it was not verified in red or green fluorescence channels and their "nuclei"-related data might be mis-interpreted.

neuroscience↗

bioRxiv2023

MRE11A: a novel negative regulator of human DNA mismatch repair

DNA mismatch repair (MMR) is a highly conserved pathway that corrects DNA replication errors. Although well characterized, MMR factors remain to be identified. As a 3-5 exonuclease and endonuclease, meiotic recombination 11 homolog A (MRE11A) is implicated in multiple DNA repair pathways. However, the role of MRE11A in MMR is unclear. Here, we show that MRE11A deficiency increased the sensitivity of HeLa cells to N-methyl-N nitro-N nitrosoguanidine (MNNG) treatment, implying a potential role of MRE11 in MMR. Moreover, we found MRE11A was largely recruited to chromatin and negatively regulated the DNA damage signals within the first cell cycle after MNNG treatment. We also showed that knockdown of MRE11A increased, while overexpressing MRE11A decreased, MMR activity in HeLa cells, suggesting that MRE11A negatively regulates MMR activity. Furthermore, we show that the recruitment of MRE11A to chromatin requires MLH1 and that MRE11A competes with PMS2 for binding to MLH1. This decreases PMS2 levels in whole cell and on chromatin, and consequently comprises MMR activity. Collectively, our findings reveal that MRE11A is a negative regulator of human MMR.

molecular biology↗

bioRxiv2023

High-throughput screening of functional neo-antigens and their specific TCRs via the Jurkat reporter system combine with droplet microfluidics

T-cell receptor (TCR)-engineered T cells can precisely recognize a broad repertoire of targets derived from both intracellular and surface proteins of tumor cells. TCR-T adoptive cell therapy has shown safety and promising efficacy in solid tumor immunotherapy. However, antigen-specific functional TCR screening is time-consuming and expensive, which limits its application clinically. Here, we developed a novel integrated antigen-TCR screening platform based on droplet microfluidics technology, enabling high-throughput peptide-major histocompatibility complex (pMHC) library-to-TCR library screening with high sensitivity and low background signal. We introduced DNA barcoding technology to label peptide antigen candidate-loaded antigen-presenting cells (APCs) and Jurkat reporter cells to check the specificity of pMHC-TCR candidates. Coupled with the next-generation sequencing pipeline, interpretation of the DNA barcodes and the gene expression level of the Jurkat T-cell activation pathway provided a clear peptide-MHC-TCR recognition relationship. Our proof-of-principle study demonstrates that the platform could achieve unbiased pMHC-TCR library-on-library screening, which is expected to be used in the cross-reactivity and off-target testing of candidate pMHC-TCR libraries in clinical applications.

bioengineering↗

bioRxiv2022

Functionally dissecting claustrum along anterior-posterior axis in anxiety and higher sensitivity to cocaine

Adolescent cocaine exposure (ACE) induce anxiety and higher sensitivity to drug addiction during adulthood. Here, we show that the claustrum is crucial for control of these two distinct psychiatric disorders in ACE mice. In the process of anxiety test, the CaMKII-positive neurons in median portion of claustrum (MClaustrum) were obviously triggered, and chemogenetic suppressing these neurons efficiently reduced ACE-induced anxiety in adulthood. While, the CaMKII-positive neurons in anterior portion of claustrum (AClaustrum) were obviously activated in response to cocaine-induced conditioned place preference (CPP), and chemogenetic suppressing these neurons efficiently blocked cocaine CPP in ACE mice during adulthood. Our findings dissociating specific sub-portions of claustrum for drug-related anxiety and susceptibility of addiction, extending our understanding to diverse functions of claustrum subregions.

neuroscience↗

bioRxiv2022

Multiplex Epigenome Editing of MECP2 to Rescue Rett Syndrome Neurons

Rett syndrome (RTT) is an X-linked neurodevelopmental disorder caused by loss-of-function heterozygous mutations of Methyl CpG-binding Protein 2 (MECP2) on the X chromosome in girls. Reactivation of the silent wild-type MECP2 allele from the inactive X chromosome (Xi) represents a promising therapeutic opportunity for female patients with RTT. Here, we applied a multiplex epigenome editing approach to reactivate MECP2 from Xi in RTT human embryonic stem cells (hESCs) and derived neurons. Demethylation of the MECP2 promoter by dCas9-Tet1 with target sgRNA reactivated MECP2 from Xi in RTT hESCs without detectable off-target effects at the transcriptional level. Neurons derived from methylation-edited RTT hESCs maintained MECP2 reactivation and reversed the smaller soma size and electrophysiological abnormalities, two hallmarks of RTT. In RTT neurons, insulation of the methylation edited MECP2 locus by dCpf1-CTCF with target CRISPR RNA enhanced MECP2 reactivation and rescued RTT-related neuronal defects, providing a proof-of-concept study for epigenome editing to treat RTT and potentially other dominant X-linked diseases. One-Sentence SummaryReactivation of MECP2 from the inactive X chromosome by multiplex epigenome editing rescues Rett syndrome neurons in vitro.

physiology↗

bioRxiv2022

Soft and stretchable organic bioelectronics for continuous intra-operative neurophysiological monitoring during microsurgery

Continuous intra-operative neurophysiological monitoring (CINM) that provides precise mapping of neural anatomy through the entire microsurgery process is essential to preserve the structural and functional integrity of the nerve. However, bulky and rigid electrodes used currently in clinics are usually unable to reliably maintain continuous and stable contacts with the vulnerable and complex nerve networks, thus often resulting in detrimental post-operative complications, such as hemiplegia and sensory disturbances. Here, we describe a biomechanically compatible, suture-free, and individually reconfigurable CINM based on soft and stretchable organic electronic materials. Due to both low impedance and modulus of our conducting polymer electrodes, we achieved for the first time continuous recording of near-field action potential with high signal-to-noise ratio and minimal invasiveness during microsurgeries. Utilizing this unprecedented CINM modality, in conjunction with localized neurostimulation, we further demonstrated our approach in enabling optimal post-operative prognosis in preclinical animal models by preserving normal neural functions after a variety of tumor resection surgeries.

bioengineering↗

bioRxiv2022

Electro-acupuncture alleviates ACE-increased anxiety-like behaviors in mice of adulthood by targeting claustrum D1R CaMKII

Adolescent cocaine exposure (ACE) increases risk of developing psychiatric problems such as anxiety, which may drive relapse in later life, however, its underlying molecular mechanism remains poorly understood. Methods: ACE male mice model were established by exposing to cocaine during adolescent period. Elevated plus maze (EPM) were used to assess anxiety-like behaviors in mice. Within claustrum, local injection of SCH-23390, a specific antagonist for dopamine receptor 1 (D1R), or D1R knocking-down virus were used to regulate D1R function or expression on CaMKII-positive neurons (D1RCaMKII) in vivo. Electro-acupuncture (EA) treatment was performed at acupoints of Baihui and Yintang during withdrawal period. Results: We found that ACE mice exhibited anxiety-like behaviors, along with more activated CaMKII-positive neurons and increased D1RCaMKII levels in claustrum during adulthood. Inhibiting D1R function or knocking-down D1RCaMKII levels in claustrum efficiently reduced claustrum activation, and ultimately suppressed anxiety-like behaviors in ACE mice during adulthood. EA treatment alleviated ACE-evoked claustrum activation and anxiety-like behaviors by suppressing claustrum D1RCaMKII. Conclusion: Our findings identified a novel role of claustrum in ACE-induced anxiety-like behaviors, and put new insight into the D1RCaMKII in the claustrum. The claustrum D1RCaMKII might be a promising pharmacological target, such as EA treatment, to treat drugs-induced anxiety-like behaviors. Graphic abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=105 SRC="FIGDIR/small/512685v5_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@1b22744org.highwire.dtl.DTLVardef@12fed83org.highwire.dtl.DTLVardef@1924caforg.highwire.dtl.DTLVardef@1e896ca_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2022

Role of mPFC DUSP1 in regulating the sensitivity to cocaine in adolescent cocaine-exposed mice of adulthood

Adolescent cocaine abuse increases the risk for developing addiction in later life, which remains a big public health concern, but the underlying molecular mechanism is poorly understood. Here, adolescent cocaine-exposed (ACE) male mice models were established by administrating cocaine during adolescent period. When growing to adult age, mice were subjected to conditioned place preference (CPP) to evaluate the sensitivity to cocaine, then potential molecule of dual specificity phosphatase 1 (DUSP1) were screened out by transcriptomic sequencing. Subthreshold dose of cocaine (sdC), that is insufficient to produce CPP, was used to induce CPP in adulthood. The sdC treatment effectively induced CPP in ACE mice during adulthood, accompanied with the more triggered CaMKII-positive neurons, and induced higher Dusp1 gene, lower DUSP1 protein, lower DUSP1 activity and lower DUSP1 expression on CaMKII-positive neurons (DUSP1CaMKII) in medial prefrontal cortex (mPFC). Overexpressing DUSP1CaMKII suppressed CaMKII-positive neuronal activation, and ultimately blocked sdC-induced CPP in ACE mice during adulthood. While, knocking-down DUSP1CaMKII activated more CaMKII-positive neurons, and aggravated sdC-preferred behavior in ACE mice during adulthood. ERK1/2 might be potential subsequent signal for DUSP1 in the process. Collectively, our findings reveal a novel molecular mechanism underlying adolescent drug abuse-induced susceptibility to addiction during adulthood, and mPFC DUSP1CaMKII is a promising pharmacological target to predict or treat addiction, especially caused by adolescent substance use. SummaryAdolescent cocaine exposure causes higher cocaine-preferred behaviors during adulthood, along with evoked mPFC activity in response to cocaine challenge. Locally overexpressing but not knocking-down the dual specificity phosphatase 1 (DUSP1) on CaMKII-positive neurons (DUSP1CaMKII) suppresses mPFC activation, and ultimately rescues the higher sensitivity to cocaine during adulthood.

neuroscience↗

bioRxiv2022

β1-adrenergic receptor on pyramidal neurons of mPFC regulates METH-preferred behaviors in METH-sired male mice

Paternal abuse of drugs, such as methamphetamine (METH), elevates the risk of developing addiction in subsequent generations, however, its underlying molecular mechanism remains poorly understood. Male adult mice (F0) were exposed to METH for 30 days, followed by mating with naive female mice to create the first-generation mice (F1). When growing to adulthood, F1 were subjected to conditioned place preference (CPP) test. Subthreshold dose of METH, insufficient to induce CPP normally, were used in F1 (METHF1). Selective antagonist (betaxolol) for {beta}1-adrenergic receptor (ADRB1) or its knocking-down virus were administrated into mPFC to regulate ADRB1 function and expression on CaMKII-positive neurons. METH-sired male F1 acquired METHF1-induced CPP, indicating that paternal METH exposure induce higher sensitivity to METH in male F1. Compared with saline (SAL)-sired male F1, CaMKII-positive neuronal activity was normal without METHF1, but strongly evoked after METHF1 treatment in METH-sired male F1 during adulthood. METH-sired male F1 had higher ADRB1 levels without METHF1, which was kept at higher levels after METHF1 treatment in mPFC. Either inhibiting ADRB1 function with betaxolol, or knocking-down ADRB1 level on CaMKII-positive neurons (ADRB1CaMKII) with virus transfection efficiently suppressed METHF1-evoked mPFC acyivation, and ultimately blocked METHF1-induced CPP in METH-sired male F1. In the process, the p-ERK1/2 and {Delta}FosB may be potential subsequent signals of mPFC ADRB1CaMKII. The mPFC ADRB1CaMKII mediates paternal METH exposure-induced higher sensitivity to drug addiction in male offspring, raising a promising pharmacological target for predicting or treating transgenerational addiction. HIGHLIGHTSO_LIPaternal methamphetamine (METH) exposure induces higher sensitivity to METH in male F1 during adulthood, accompanied with higher ADRB1 level in mPFC. C_LIO_LIMETH use in F1 (METHF1) evokes more CaMKII-positive neurons in mPFC of METH-sired than saline-sired male F1. C_LIO_LIInhibiting ADRB1 function or knocking-down ADRB1 level on CaMKII-positive neurons (ADRB1CaMKII) efficiently suppresses METHF1-evoked mPFC activation, and ultimately rescues transgenerational susceptibility to addiction in male F1. C_LI

neuroscience↗

bioRxiv2022

Activation of Cerebellar Lobule VI PCTH+boxhMed Pathway Selectively blocks METH-induced Conditioned Place Preference in mice

The cerebellum is implicated in drug addiction. However, the cerebellar neuronal circuitry underlying addiction, especially classic pathway of Purkinje cells (PCs) to deep cerebellar nuclei (DCN), are largely unknown. Here, tracing experiments showed robust projections from the cerebellar lobule VI tyrosine hydroxylase (TH)-positive PCs (PCTH+) to CaMKII-positive glutamatergic neurons in medial cerebellar nucleus (MedCaMKII), forming PCTH+-MedCaMKII pathway. Then, mice were subjected to methylamphetamine (METH)-induced conditioned place preference (CPP), showing that METH exposure excited MedCaMKII and inhibited PCTH+. Silencing MedCaMKII by tettox suppressed the formation and expression of METH-induced CPP, but produced serious motor coordination deficits. Chemogenetic activation of lobule VI PCTH+-Med pathway during METH CPP training blocked the formation and expression of METH-induced CPP without affecting motor coordination, locomotor activity and sucrose reinforcements in mice. Our findings revealed a novel cerebellar lobule VI PCTH+-MedCaMKII pathway and pointed out is critical role in encoding METH-preferred behaviors.

neuroscience↗

bioRxiv2022

Streptococcus suis infection on European farms is associated with an altered tonsil microbiome and resistome

Streptococcus suis is a Gram-positive opportunistic pathogen causing systemic disease in piglets around weaning age. The factors predisposing to disease are not known. We hypothesised that the tonsillar microbiota might influence disease risk via colonisation resistance and/or co-infections. We conducted a cross-sectional case-control study within outbreak farms complemented by selective longitudinal sampling and comparison with control farms without disease occurrence. We found a small but significant difference in tonsil microbiota composition between case and control piglets (n=45+45). Variants of putative commensal taxa, including Rothia nasimurium, were reduced in abundance in case piglets compared to asymptomatic controls. Case piglets had higher relative abundances of Fusobacterium gastrosuis, Bacteroides heparinolyticus, and uncultured Prevotella and Alloprevotella species. Despite case-control pairs receiving equal antimicrobial treatment, case piglets had higher abundance of antimicrobial resistance genes (ARGs) conferring resistance to antimicrobial classes used to treat S. suis. This might be an adaption of disease-associated strains to frequent antimicrobial treatment.

microbiology↗

bioRxiv2022

The GC box at the proximal enhancer of the Hdc gene is critical for Hdc gene transcription and histamine-mediated anaphylaxis

Background: Histamine is a critical mediator of anaphylaxis, a neurotransmitter, and a regulator of gastric acid secretion. Histidine decarboxylase is a rate-limiting enzyme for histamine synthesis. However, in vivo regulation of Hdc, the gene that encodes histidine decarboxylase is poorly understood. Objective: We sought to investigate how enhancers regulate Hdc gene transcription and histamine synthesis in resting conditions and in a mouse model of anaphylaxis. Methods: H3K27 acetylation histone modification and chromatin accessibility were used to identify candidate enhancers; The enhancer activity of candidate enhancers was measured in a reporter gene assay; and the function enhancers were validated using CRISPR deletion. Results: Deletion of the GC box, which binds to zinc finger transcription factors, in the proximal Hdc enhancer, reduced Hdc gene transcription and histamine synthesis in the mouse and human mast cell lines. Mast cells, basophils, brain cells, and stomach cells from GC box-deficient mice transcribed the Hdc gene much less than similar cells from wild-type mice and Hdc GC box-deficient mice failed to develop anaphylaxis. Conclusion: Our results demonstrate that the HDC GC box within the proximal enhancer in the mouse and human HDC gene is essential for Hdc gene transcription, histamine synthesis, and histamine-mediated anaphylaxis in vitro and in vivo. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=104 SRC="FIGDIR/small/495950v3_ufig1.gif" ALT="Figure 1"> View larger version (40K): org.highwire.dtl.DTLVardef@106f99org.highwire.dtl.DTLVardef@10ec8b8org.highwire.dtl.DTLVardef@19bb1ceorg.highwire.dtl.DTLVardef@b663cd_HPS_FORMAT_FIGEXP M_FIG C_FIG Key messages: O_LIThe HDC GC box within the proximal enhancer of the mouse and human HDC gene is essential for Hdc gene transcription and histamine synthesis in mouse and human mast cells. C_LIO_LIThe mouse Hdc GC box is required for histamine-mediated anaphylaxis in vivo. C_LI Capsule summary Our results demonstrate that the Hdc GC box within the proximal enhancer of the mouse and human HDC gene is essential for Hdc gene transcription and histamine synthesis in mast cells. The mouse Hdc GC box is required for histamine-mediated anaphylaxis in the mouse model of anaphylaxis.

immunology↗

bioRxiv2022

A distal enhancer is required for TNF gene transcription in human macrophages in response to TLR3 stimulation

Macrophages play a critical role in inflammatory responses during infections. These cells are activated by infections through stimulation of TLRs expressed on their cell surface and produce pro-inflammatory cytokines, including TNF. However, distal enhancers that regulate TNF gene transcription in human macrophages have not been investigated. This study used an unbiased genomic approach to identify six candidate enhancers in human primary alveolar macrophages within a 131 kb region from the transcription start site (TSS) of the TNF gene, covering 13 genes. Of these candidate enhancers, five showed enhancer activity, with three targeting the TNF gene and two targeting neighboring genes. Deletion of the distal TNF E-16 enhancer led to a 73% reduction in TNF gene transcription in response to poly (I:C) stimulation in the THP-1 human leukemia monocytic cell line. Additionally, deletion of the E-7.1/hHS-8 enhancer resulted in a 41% reduction in TNF mRNA, while deletion of the PE enhancer had a lesser effect, resulting in a 52% reduction in TNF gene transcription. Massively parallel reporter assays (MPRA) indicated that the transcription factor AP-1 and EGR1-binding sites at the distal TNF E-16 enhancer were crucial in mediating enhancer activity. This study shows that both distal and proximal enhancers work together to fully transcribe the TNF gene in human macrophages in response to TLR ligand poly (I:C) stimulation.

immunology↗

bioRxiv2022

Genetic or transcranial magnetic stimulation of B-RAF-MEK signaling promotes CST axon sprouting and functional regeneration

Facilitating axon regeneration in the injured central nervous system remains a challenging task. RAF-MEK signaling plays an important role in axon elongation during nervous system development. Here we show that activation of B-RAF in mature corticospinal neurons elicited the expression of a discrete set of transcription factors previously implicated in the regeneration of zebrafish optic nerve axons. Genetic activation of B-RAF-MEK signaling promoted robust regeneration and sprouting of corticospinal tract axons after injury. Newly sprouting axon collaterals formed synaptic connections with spinal interneurons, correlating with the recovery of skilled motor function. Seeking a non-invasive way to stimulate axon regeneration, we found that suprathreshold high-frequency repetitive transcranial magnetic stimulation activates the B-RAF canonical effectors MEK1/2 and requires MEK1/2 activity to promote corticospinal axon regeneration and sprouting after injury. These data demonstrate a central role of neuron-intrinsic RAF-MEK signaling in enhancing the growth capacity of mature corticospinal neurons and propose HF-rTMS as a potential therapy for spinal cord injury. One Sentence SummaryGenetic or HF-rTMS-mediated activation of B-RAF- MEK signaling promotes CST axon sprouting and functional regeneration after a spinal cord injury.

neuroscience↗