Biology subjects

Li, X.-M.

Publications and source records attributed to Li, X.-M..

14 recordsLinked to original sources

bioRxiv2026

Single-cell spatial transcriptomics and snRNA-seq decoding the organizational principles of functional modules in the mouse amygdala

The amygdala is a functionally heterogeneous nuclear complex comprising multiple subnuclei that orchestrate diverse behaviors, making it essential for survival and reproduction. However, the precise neural mechanisms underlying these heterogeneous functions remain elusive, primarily due to limited knowledge of the amygdalas cellular heterogeneity, developmental origins, spatial organization, and gene expression profiles. Here, we integrate single-cell-resolution spatial transcriptomics with precise anatomical dissection and single-nucleus RNA sequencing to systematically map the subnuclear enrichment patterns of amygdalar cell types. We further demonstrate that developmental origin determines subnuclear positioning and propose a novel functional modular architecture based on cellular composition and gene expression signatures. Furthermore, we reveal that the central amygdala (CEA) exhibits developmental heterogeneity, with Isl1+ neurons in its medial subdivision (CEAm) predominantly originating from hypothalamic progenitors. Our findings establish a spatially resolved cellular and molecular framework for investigating amygdalar functions at cellular type resolution and understanding amygdala-related neuropsychiatric disorders.

neuroscience↗

bioRxiv2025

Transcriptomic and spatial GABAergic neuron subtypes in zona incerta mediate distinct innate behaviors

Understanding the anatomical connection and behaviors of transcriptomic neuron subtypes is critical to delineating cell type-specific functions in the brain. Here we integrated single-nucleus transcriptomic sequencing, in vivo circuit mapping, optogenetic and chemogenetic approaches to dissect the molecular identity and function of heterogeneous GABAergic neuron populations in the zona incerta (ZI) in mice, a region involved in modulating various behaviors. By microdissecting ZI for transcriptomic and spatial gene expression analyses, our results revealed two non-overlapping Ecel1- and Pde11a-expressing GABAergic neurons with dominant expression in the rostral and medial zona incerta (ZIrEcel1 and ZImPde11a), respectively. The GABAergic projection from ZIrEcel1 to periaqueductal gray mediates self-grooming, while the GABAergic projection from ZImPde11a to the oral part of pontine reticular formation promotes transition from sleep to wakefulness. Together, our results revealed the molecular markers, spatial organization and specific neuronal circuits of two discrete GABAergic projection neuron populations in segregated subregions of the ZI that mediate distinct innate behaviors, advancing our understanding of the functional organization of the brain.

neuroscience↗

bioRxiv2025

Comprehensive Infectome Analysis Reveals Diverse Infectious Agents with Zoonotic Potential in Wildlife

Understanding wildlife-pathogen interactions is crucial for mitigating zoonotic risk. Through meta-transcriptomic sequencing we profiled the infectomes of 1,922 samples from 67 mammalian species across China, uncovering a remarkable diversity of viral, bacterial, fungal, and parasitic pathogens. Of the 195 pathogens identified, 62 were novel, including a bi- segmented coronavirus in diseased lesser pandas, which we propose represents a new genus - Zetacoronavirus. The orders Carnivora and Rodentia exhibited the highest pathogen diversity and were implicated in numerous host-jumping events. Comparative analysis of diseased versus healthy animals revealed a trend of higher pathogen loads in the former, with possible differences in tissue tropisms. In total, 48 zoonotic and 17 epizootic pathogens were identified, with frequent cross-species transmission, emphasizing the potential for emerging public health threats. This study highlights the urgent need for wildlife pathogen surveillance to inform proactive disease management strategies.

microbiology↗

bioRxiv2024

Male Mice Have no Sugar-preference Behavior

Sugar-preference behavior is considered to be universally innate among humans and animals. Current research on the detection and mechanisms of sugar-preference behavior largely adopts the "two-bottle choice assay", and most experiments use male mice as the model, which has serious methodological flaws, leading to questionable conclusions. As expected, through adopting our improved experimental method, we discovered distinct sugar preferences between male and female mice: females possess an innate preference, while males do not. However, the innate sugar preference in female mice can be lost due to their long-term normal diet. Even after "training" with high-sugar food for a long time, the results still show differences between males and females. Female mice retain a significant preference for sugar, while male mice are not influenced by the training of high-sugar food and still do not evolve a sugar preference. From this, we conclude that gender determines the emergence and development of sugar preference in mice. Our results can provide researchers with a new understanding of sugar preference, which will help them fill in or even correct the gaps in the original experimental design methods to obtain more reliable conclusions.

animal behavior and cognition↗

bioRxiv2024

Multimodal single-cell analyses reveal molecular markers of neuronal senescence in human drug-resistant epilepsy

The histopathological neurons in the brain tissue of drug-resistant epilepsy exhibit aberrant cytoarchitecture and imbalanced synaptic circuit function. However, the gene expression changes of these neurons remain unknown, making it difficult for the diagnosis or to dissect the mechanism of drug-resistant epilepsy. By integrating whole-cell patch clamp recording and single-cell RNA sequencing approaches, we identified a transcriptionally distinct subset of cortical pyramidal neurons. These neurons highly expressed genes CDKN1A (P21), CCL2 and NFKBIA that associated with mTOR pathway, inflammatory response and cellular senescence. We confirmed the expression of senescent marker genes in a subpopulation of cortical pyramidal neurons with enlarged soma size in the brain tissue of drug-resistant epilepsy. We further revealed the expression of senescent cell markers P21, P53, COX2, {gamma}-H2AX, {beta}-Gal and reduction of nuclear integrity marker Lamin B1 in histopathological neurons in the brain tissue of drug-resistant epilepsy patients with different pathologies, but not in control brain tissue with no history of epilepsy. Additionally, chronic, but not acute, epileptic seizures induced senescent markers expression in cortical neurons in mouse models of drug-resistant epilepsy. These results provide important molecular markers for histopathological neurons and new insights into the pathophysiological mechanisms of drug-resistant epilepsy.

neuroscience↗

bioRxiv2024

HCN1 channels in GABAergic amygdalar neurons underpin male-biased aggressive behaviors

Aggression behaviors typically vary between sexes, but the molecular mechanisms driving these disparities in neural coding are unclear. We found that aggression selectively activates GABAergic neurons in the posterior substantia innominata (pSI), an extend amygdala region critical for aggressive behaviors in both sexes of mice, with males exhibiting higher neuronal activity during the attack. Utilizing single-nucleus RNA sequencing, we characterized the diverse molecular landscape of pSI neurons, revealing significant differences in ion channels and hormone regulator genes that may underpin sex-specific aggression. Male GABAergic pSI neurons exhibited remarkable hyperexcitability due to increased Ih currents. Strikingly, modulating HCN1 expression not only adjusted this hyperexcitability but also influenced sexual dimorphism in aggression: silencing HCN1 in the GABAergic pSI neurons reduced male aggression, while its overexpression markedly heightened aggression in females. Furthermore, testosterone was shown to intensify aggression by upregulating HCN1 and remodeling pSI circuits. These findings provide detailed sex-specific molecular mechanisms underlying social behaviors.

neuroscience↗

bioRxiv2024

Berberine: A dual anti-HIV and anti- cervical cancer compound

We report the effects of berberine (BBR), a benzylisoquinoline alkaloid small molecule on inhibition of HIV infection of cervical cancer cells. We used HeLa cell-derived TZM-bl cell line as a model of cervical cancer and HIV infection. BBR significantly inhibits viral and cancer processes, including expression of cell-associated HIV RNA, secretion of HIV reverse transcriptase, and HIV Tat-mediated LTR promoter transactivation. BBR significantly inhibits HIV-induced cancer cell viability and cell clustering. Besides its ability to inhibit HIV-induced cancer cell viability, BBR inhibits migration and matrix invasion of cervical cancer cells that are infected with HIV or treated with HIV Tat protein. The ability of BBR to inhibit cell clustering, collective cell migration, and cell invasion may have an effect in controlling progression of cervical cancer and HIV since collective migration and invasion are strategies for local tissue infiltration, as well as metastatic invasion in epithelial cancers. Interestingly, molecular docking and dynamic stimulation show that BBR binds HIVIIIB Tat amino acid residues through non-covalent interactions that occurs at multiple sites including LYS71, providing mechanistic insights into BBR regulation HIV infection. The results of the present study suggest that BBR has the potential to inhibit HIV infection and comorbid cervical cancer progression. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=67 SRC="FIGDIR/small/624212v1_ufig1.gif" ALT="Figure 1"> View larger version (20K): org.highwire.dtl.DTLVardef@1b88635org.highwire.dtl.DTLVardef@17311d8org.highwire.dtl.DTLVardef@19881c7org.highwire.dtl.DTLVardef@170483a_HPS_FORMAT_FIGEXP M_FIG C_FIG Berberine (BBR), a benzylisoquinoline alkaloid small molecule, inhibits HIV infection of cervical cancer cells, suppresses HIV-induced migration and invasion of the cancer cells. Mechanistically, BBR interferes with Tat-mediated HIV LTR promoter transactivation and expression of different HIV RNA species, expression of early genes (multiply spliced Tat-Rev) and late genes (unspliced Gag-Pol).

molecular biology↗

bioRxiv2024

Age-associated growth control modifies leaf proximodistal symmetry and enables leaf shape diversification

Biological shape diversity is often manifested in modulation of organ symmetry and modification of the patterned elaboration of repeated shape elements.1-5 Whether and how these two aspects of shape determination are coordinately regulated is unclear.5-7 Plant leaves provide an attractive system to investigate this problem, because they usually show asymmetries along their proximodistal axis, along which they can also produce repeated marginal outgrowths such as serrations or leaflets.1 One case of leaf shape diversity is heteroblasty, where the leaf form in a single genotype is modified with progressive plant age.8-11 In Arabidopsis thaliana, a plant with simple leaves, SQUAMOSA PROMOTER BINDING PROTEIN-LIKE9 (SPL9) controls heteroblasty by activating CyclinD3 expression, thereby sustaining proliferative growth and retarding differentiation in adult leaves.12 However, the precise significance of SPL9 action for leaf symmetry and marginal patterning is unknown. By combining genetics, quantitative shape analyses, and time-lapse imaging, we show that, in A. thaliana, proximodistal symmetry of the leaf blade decreases in response to an age-dependent SPL9 expression gradient, and that SPL9 action coordinately regulates the distribution and shape of marginal serrations and overall leaf form. Using comparative analyses, we demonstrate that heteroblastic growth reprogramming in Cardamine hirsuta, a complex-leafed relative of A. thaliana, also involves prolonging the duration of cell proliferation and delaying differentiation. We further provide evidence that SPL9 enables species-specific action of homeobox genes that promote leaf complexity. In conclusion, we identify an age-dependent layer of organ proximodistal growth regulation that modulates leaf symmetry and has enabled leaf shape diversification. In BriefAge-dependent regulation of proliferative growth and differentiation along the proximodistal axis of leaves modulates organ symmetry and marginal patterning in heteroblasty, and enabled the action of homeobox genes in complex leaf shape evolution. HighlightsO_LIAn age-dependent growth gradient underpins regulation of A. thaliana leaf symmetry C_LIO_LISPL9-mediated heteroblastic growth control potentiates leaf histogenic capacity C_LIO_LIA common growth framework underlies heteroblasty in complex and simple leaves C_LIO_LISPL9 enables the action of homeobox genes that promote leaf complexity C_LI

developmental biology↗

bioRxiv2023

MdMYB44-like positively regulates salt and drought tolerance via the MdPYL8-MdPP2CA module in apple

Abscisic acid (ABA) is involved in salt and drought stress responses, but the underlying molecular mechanism remains unclear. Here, we demonstrated that the overexpression of MdMYB44-like, an R2R3-MYB transcription factor (TF), significantly increases the salt and drought tolerance of transgenic apple and Arabidopsis. MdMYB44-like inhibits the transcription of MdPP2CA, which encodes a type 2C protein phosphatase that acts as a negative regulator in ABA response, thereby enhancing ABA signaling-mediated salt and drought tolerance. Furthermore, we found that MdMYB44-like and MdPYL8, an ABA receptor, form a protein complex that further enhances the transcriptional inhibition of the MdPP2CA promoter by MdMYB44-like. Significantly, we discovered that MdPP2CA can interfere with the physical association between MdMYB44-like and MdPYL8 in the presence of ABA, partially blocking the inhibitory effect of the MdMYB44-like-MdPYL8 complex on the MdPP2CA promoter. Thus, MdMYB44-like, MdPYL8, and MdPP2CA form a regulatory loop that tightly controls ABA signaling homeostasis under salt and drought stress. Our data revealed a previously unidentified mechanism by which MdMYB44-like precisely modulates ABA-mediated salt and drought tolerance in apple through the MdPYL8-MdPP2CA module.

plant biology↗

bioRxiv2022

Super-resolution imaging reveals dynamic skeletal cytoophidia

CTP synthase (CTPS) can form filamentous structures termed cytoophidia in cells from all three domains of life. In order to study the mesoscale structure of cytoophidia, we perform fluorescence recovery after photobleaching (FRAP) and stimulated emission depletion (STED) microscopy in human cells. By using EGFP dimeric tag, as a tool to explore the physical properties of cytoophidia, we find that cytoophidia are dynamic and reticular. The reticular structure of CTPS cytoophidia may provide space for other components such as IMPDH. In addition, we observe CTPS granules with tentacles.

biophysics↗

bioRxiv2022

Induction of Anxiety-Like Phenotypes by Knockout of Cannabinoid Type-1 Receptor in Amygdala of Marmosets

The amygdala is an important hub for the regulation of emotions, which is crucial for elucidating cellular and molecular mechanisms of many mental diseases. In the central nervous system, the endocannabinoid system plays a key role in the regulation of emotions and mainly functions through the cannabinoid type-1 receptor (CB1R), which is encoded by the Cnr1 gene. Although CB1R is highly expressed in the amygdala of non-human primates, little is known about its function. Here, we investigated the function of CB1R by knocking out the CB1R in the amygdala of adult marmosets through regional delivery of AAV-SaCas9-gRNA. We found that CB1R knockout in the amygdala of marmosets induced anxiety-like behaviors, including disrupted night sleep, agitated psychomotor activity in new environments, and reduced social desire, but had no effect on hedonic state and fear response. Moreover, CB1R-knockout marmosets exhibited up-regulated plasma cortisol levels, suggesting increased stress. These results showed that knockout of CB1R in the amygdala induced anxiety-like phenotypes in marmosets and shed new light on the mechanisms underlying the regulation of anxiety by CB1R in the amygdala of non-human primates.

neuroscience↗

bioRxiv2022

Two-photon patterned photostimulation with low-power, high-efficiency and reliable single-cell optogenetic control

Two-photon optogenetics enables selectively stimulating individual cells for manipulating neuronal ensembles. As the general photostimulation strategy, the patterned two-photon excitation has enabled millisecond-timescale activation for single or multiple neurons, but its activation efficiency is suffered from high laser power due to low beam-modulation efficiency. Here, we develop a high- efficiency beam-shaping method based on the Gerchberg-Saxton (GS) algorithm with spherical-distribution initial phase (GSSIP) to reduce the patterned two-photon excitation speckles and intensity. It can well control the phase of shaped beams to attain speckle-free accurate patterned illumination with an improvement of 44.21% in the modulation efficiency compared with that of the traditional GS algorithm. A combination of temporal focusing and the GSSIP algorithm (TF-GSSIP) achieves patterned focusing through 500-m-thickness mouse brain slices, which is 2.5 times deeper than the penetration depth of TF-GS with the same signal-to-noise ratio (SNR). With our method, the laser power can be reduced to only 55.56% of that with traditional method (the temporal focusing with GS, TF-GS) to reliably evoke GCaMP6s response in C1V1-expressing cultured neurons with single-cell resolution. Besides, the photostimulation efficiency is remarkably increased by 80.19% at the same excitation density of 0.27 mW/m2. This two-photon stimulation method with low-power, reliable and patterned illumination may pave the way for analyzing neural circuits and neural coding and decoding mechanism.

neuroscience↗

bioRxiv2020

Study on β-Chitosan against the binding of SARS-CoV-2S-RBD/ACE2

SARS-CoV-2 invades human respiratory epithelial cells via an interaction between its spike RBD protein (SARS-CoV-2 S-RBD) and the host cell receptor angiotensin converting enzyme II (ACE2). Blocking this interaction provides a potent approach to preventing and controlling SARS-CoV-2 infection. In this work, the ability of {beta}-chitosan to block the binding interaction between SARS-CoV-2 S-RBD and ACE2 was investigated. The inhibitory effect of {beta}-chitosan on inflammation induced by the SARS-CoV-2 S-RBD was also studied. Native-PAGE analysis indicated that {beta}-chitosan could bind with ACE2 and the SARS-CoV-2 S-RBD and a conjugate of {beta}-chitosan and ACE2 could no longer bind with the SARS-CoV-2 S-RBD. HPLC analysis suggested that a conjugate of {beta}-chitosan and the SARS-CoV-2 S-RBD displayed high binding affinity without dissociation under high pressure (40 MPa) compared with that of {beta}-chitosan and ACE2. Furthermore, immunofluorescent staining of Vero E6 cells and lungs from hACE2 mice showed that the presence of {beta}-chitosan prevented SARS-CoV-2 S-RBD from binding to ACE2. Meanwhile, {beta}-chitosan could dramatically suppress the inflammation caused by the presence of the SARS-CoV-2 S-RBD both in vitro and vivo. Moreover, the decreased expression of ACE2 caused by {beta}-chitosan treatment was restored by addition of TAPI-1, an inhibitor of the transmembrane protease ADAM17. Our findings demonstrated that {beta}-chitosan displays an antibody-like function capable of neutralizing the SARS-CoV-2 S-RBD and effectively preventing the binding of the SARS-CoV-2 S-RBD to ACE2. Moreover, ADAM17 activation induced by {beta}-chitosan treatment can enhance the cleavage of the extracellular domain of ACE2, releasing the active ectodomain into the extracellular environment, which can prevent the binding, internalization, and degradation of ACE2 bound to the SARS-CoV-2 S-RBD and thus diminish inflammation. Our study provides an alternative avenue for preventing SARS-CoV-2 infection using {beta}-chitosan.

cell biology↗

bioRxiv2018

ErbB4 deletion in noradrenergic neurons in the locus coeruleus induces mania-like behavior via elevated catecholamines

Dysfunction of the noradrenergic (NE) neurons is implicated in the pathogenesis of manic-depressive psychosis (MDP). ErbB4 is highly expressed in NE neurons, and its genetic variation has been linked to MDP; however, how ErbB4 regulates NE neuronal function and contributes to MDP pathogenesis is unclear. Here we find that conditional deletion of ErbB4 in locus coeruleus (LC) NE neurons increases neuronal spontaneous firing through NMDA receptor hyperfunction, and elevates catecholamines in the cerebrospinal fluid (CSF). Furthermore, ErbB4-deficient mice present mania-like behaviors, including hyperactivity, reduced anxiety and depression, and increased sucrose preference. These behaviors are completely rescued by the anti-manic drug lithium or antagonists of catecholaminergic receptors. Our study demonstrates the critical role of ErbB4 signaling in regulating LC-NE neuronal function, reinforcing the view that dysfunction of the NE system may contribute to the pathogenesis of mania-associated disorder.

neuroscience↗