Biology subjects

Jing, L.

Publications and source records attributed to Jing, L..

At least 19 recordsLinked to original sources

bioRxiv2026

A Synergistic Terpenoid-Phenolic Defense Network Confers Resistance to Dendrolimus superans in Hybrid Larch

To elucidate the resistance of hybrid larch (Larix spp.) clones to Dendrolimus superans and their chemical defense mechanisms, 46 clones were subjected to field feeding-infestation experiments. Insect resistance was comprehensively evaluated by the membership function method from three perspectives: insect weight change, frass weight and defoliation rate (damage consequences); pre- and post-infestation physiological indices (constitutive and induced resistance). High- and low-resistance materials screened from each perspective were further analyzed by widely targeted LC-MS metabolomics. The three damage indices differed highly significantly among clones (P<0.01) and were positively correlated, indicating abundant genetic variation in resistance. Clones such as -30-C, -35-A and -21-A showed strong overall resistance, whereas -28-E and -20-A showed high constitutive and induced resistance. Defence enzyme activities (POD, SOD, CAT, PPO and PAL) correlated closely with secondary metabolites (total phenolics, tannins and total flavonoids) and nutrients, and rose synergistically after feeding, reflecting synergy between constitutive and induced resistance. In total, 3,577 metabolites were identified, predominantly terpenoids (>90%). The three groups yielded 1,010, 1,086 and 922 differentially accumulated metabolites, and PCA separated high- from low-resistance materials in all groups. These metabolites were significantly enriched in metabolic pathways, biosynthesis of secondary metabolites, monoterpenoid and diterpenoid biosynthesis, and phenylpropanoid biosynthesis. In conclusion, resistance of hybrid larch to D. superans is jointly conferred by the defence enzyme system, secondary metabolite accumulation and a 'terpenoid-phenolic' metabolic network: terpenoids and phenolics act synergistically via the terpenoid and phenylpropanoid pathways, together forming the core of chemical defense and supporting the breeding of insect-resistant clones.

plant biology↗

bioRxiv2026

Myeloid-targeted RNA nanotherapeutics rewire cholesterol metabolism to unleash anti-tumor immunity in glioblastoma

Tumor-associated myeloid cells (TAMCs) dominate the glioblastoma (GBM) microenvironment and suppress anti-tumor immunity. Here, we identify cholesterol efflux via ABCA1 as a targetable metabolic checkpoint controlling TAMC immunosuppression in GBM. Reprogramming TAMC cholesterol metabolism using TAMC-targeting lipid nanoparticle encapsulating ABCA1 siRNA (ABCA1 LNP) converts TAMCs into potent antigen-presenting cells with enhanced pro-inflammatory activity and antigen-presenting capacity, thereby inducing T cell activation, expansion, and tumor infiltration. Mechanistically, ABCA1 blockade induces cholesterol accumulation in TAMC membranes, promoting lipid raft formation and enhancing MHC-I-mediated antigen presentation. In multiple preclinical GBM models, ABCA1 LNP treatment dramatically induces T cell priming, extends animal survival, and overcomes GBM resistance to radiotherapy and immune checkpoint therapy. This efficacy was well-maintained in stem-like and recurrent GBM models, GBM patient specimens, and a renal cell carcinoma model. Altogether, our work identifies cholesterol efflux as a targetable metabolic vulnerability in TAMCs to overcome therapy resistance in myeloid-rich, immunologically "cold" tumors.

immunology↗

bioRxiv2026

A PDMS-based microfluidic platform enabling dual biochemical and electric-field stimulation for modeling sensory neuron-intervertebral disc crosstalk

Inflammation-driven increases in nociception are prominent in pain pathologies associated with intervertebral disc (IVD) degeneration yet are difficult to model in vitro. Since neurons are exposed to multi-modal stimuli in vivo, it is critical for these exposures to be conserved in an in vitro test system. We developed a polydimethylsiloxane (PDMS)-based microfluidic platform to interrogate peripheral sensory neurons (SNs) in the presence of conditioned media from nucleus pulposus cells from the degenerated IVD, to model a potential impact of IVD cells secretome on pain sensing. Our platform enables controlled perfusion of cell-derived biochemical cues alongside a defined homogeneous electric field (EF) and supports real-time optical analysis. Computational modeling, fluid perfusion experiments, and conductivity measurements confirmed stable fluid transport and tunable homogeneous EF generation within the device. As proof of concept for neuronal stimulation, neuroblastoma (N2a) cells loaded with a fluorescent Ca2+ indicator exhibited a 56% increase in Ca2+ transient activity when exposed to media from degenerated IVDs, concomitant with increased IVD-derived IL-1{beta} production. Importantly, EF-stimulated Ca2+ transients increased in SNs derived from human induced pluripotent stem cells when exposed to conditioned media from primary human IVD cells, demonstrating the translation of this model system to human cells. Together, these results establish a versatile platform that enables controlled and simultaneous exposure to biochemical and electrical stimuli to quantify inflammation-driven peripheral neuronal hyperexcitability in tissue-neuron crosstalk.

bioengineering↗

bioRxiv2026

Cytotoxic T cells targeting lytic KSHV gene products infiltrate Kaposi sarcoma tumors

Kaposi sarcoma-associated herpesvirus (KSHV) is the etiologic agent of Kaposi sarcoma (KS), primary effusion lymphoma (PEL), and KSHV-associated multicentric Castlemans disease (MCD), malignancies that predominantly arise in the context of T-cell deficiency. Unlike responses to other human herpesviruses such as EBV and CMV, KSHV-specific T-cell responses detected in blood have been described as heterogeneous and low-intensity. Hypothesizing that KSHV-specific T cells are recruited to KS tumors, we analyzed the T-cell receptor (TCR) repertoire of biopsies from 144 Ugandan adults with KS (106 people living with HIV [PLWH], 38 HIV-seronegative) and identified >4,000 {beta} TCRs with predicted specificity for KSHV- or HIV-encoded peptides presented by specific MHC alleles. We tested 14 putative KSHV- or HIV-specific TCRs for recognition of cells presenting cognate peptides in the predicted MHC context. Three novel HIV-specific TCRs, found only in tumors from PLWH, exhibited high-avidity, MHC-restricted recognition of HIV Vpr and Nef peptides previously identified as CD8+ T-cell targets. Four KSHV-specific TCRs, detected in tumors from both PLWH and HIV-seronegative individuals, recognized peptides encoded by the lytic KSHV genes ORF6, ORF57, and ORF59. The ORF6- and ORF57-specific TCRs were observed in multiple individuals and constitute the first examples of public T-cell responses to KSHV. We then confirmed that these four KSHV-specific TCRs recognized KSHV-infected cells undergoing lytic reactivation. Identification of TCRs specific for KSHV lytic gene products will enable the development of T-cell-based therapies for KS and other KSHV-associated diseases. Author summaryKaposi sarcoma-associated herpesvirus (KSHV) is the only oncogenic human virus for which there is no effective vaccine, antiviral, or immunotherapeutic strategy that directly targets the virus. KSHV is the causative agent of Kaposi sarcoma and primary effusion lymphoma, cancers that primarily affect immunocompromised individuals, most commonly people living with HIV in sub-Saharan Africa, where KSHV is endemic and HIV infection is prevalent. In this study we defined the antigenic specificity of novel, putative KSHV- and HIV-specific T-cell receptors (TCRs) that are carried in T cells commonly infiltrating KS tumor biopsies. We show that T cells engineered to express KSHV-specific TCRs exhibit high-avidity, MHC-restricted recognition of KSHV-infected cells presenting naturally processed peptides encoded by KSHV lytic genes. Our findings provide a blueprint for dissecting KSHV-specific T-cell immunity and advancing the development of immunotherapeutic strategies for the prevention or treatment of KSHV-associated diseases.

immunology↗

bioRxiv2025

Ultra-wide-field, deep, adaptive two-photon microscopy

Observing the activity patterns of large neural populations throughout the brain is essential for understanding brain function. However, capturing neural interactions across widely distributed brain regions from both superficial and deep cortical layers remains challenging with existing microscopy technologies. Here, we introduce a state-of-the-art two-photon microscopy system, ULTRA, capable of single-cell resolution imaging across an ultra-large field of view (FOV) exceeding 50 mm{superscript 2}, enabling deep and very wide field in vivo imaging. To demonstrate its capabilities, we conducted a series of experiments under multiple imaging conditions, successfully visualizing brain structures and neuronal activities spanning a spatial range of over 7 mm from superficial layers to depths of up to 900 m, while covering a volume of 45.24 mm3 in the mouse brain. This versatile imaging platform overcomes traditional spatial constraints, providing a powerful tool for comprehensive exploration of neuronal circuitry over extensive spatial scales with cellular resolution.

neuroscience↗

bioRxiv2025

Ablation of VEGFA following a lumbar intervertebral disc injury attenuates intradiscal neurovascular features and prevents chronic low back pain symptoms

Despite its enormous burden on patients and society, chronic low back pain (LBP) has no effective therapeutic options. Innervation of the degenerating intervertebral disc (IVD) is suspected to cause discogenic LBP, but the mechanisms that orchestrate the IVDs neo-innervation and subsequent symptoms of LBP remain unknown. We hypothesize that Vascular Endothelial Growth Factor-A (VEGFA) critically mediates the neurite invasion in the IVD and contributes to chronic LBP. Initiating IVD degeneration through a mechanical injury, we evaluated the progression of neurovascular features into the IVD, as well as ensuring LBP symptoms and locomotive impairments at acute (3-weeks) and chronic (12-weeks) timepoints following the IVD injury. To determine the role of VEGFA, we utilized a mouse model with ubiquitously inducible recombination of the floxed Vegfa allele (UBC-CreERT2; Vegfafl/fl). The ablation of VEGFA after an IVD injury attenuated de novo neurite and vessel infiltration and impeded the expression of TRPA1, a nociceptive ion channel, in the dorsal root ganglion. The VEGFA-null animals, despite IVD degeneration, exhibited alleviated mechanical allodynia and improved locomotive performance. To determine the effects of IVD-derived VEGFA on endothelial cells and neurons, we co-cultured HMEC-1 endothelial cells and SH-SY5Y neurons with VEGFA-silenced human primary IVD cells. The endothelial cells co-cultured with VEGFA-silenced IVD cells exhibited reduced vessel growth and shifted their transcriptome and secretome from angiogenic to lymphangiogenic. The neurons co-cultured VEGFA-silenced IVD cells showed slowed growth and attenuated transcriptional programs for growth and elongation. These results show that VEGFA directs the growth of intradiscal vessels and neurites that cause low back pain and impaired function, and the inhibition of IVD-derived VEGFA during degeneration may be sufficient to prevent chronic pain behavior and motor impairment associated with discogenic low back pain. One Sentence SummaryVEGFA is a key mediator of neurovascular infiltration in the degenerating intervertebral disc and an essential driver of chronic low back pain, whose ablation prevents pain-related behaviors.

neuroscience↗

bioRxiv2025

The genomic and transcriptional landscape of the spinal cord H3K27-altered diffuse midline glioma suggests the potential therapeutic strategy

Diffuse midline glioma with H3K27-altered (DMG) is a lethal pediatric malignancy that primarily occurs in the brainstem of children. In adults, DMG arising in the spinal cord is rarely reported and remains poorly understood. The cellular architecture and clinical outcomes of DMG vary depending on the tumors location. To dissect the genomic and transcriptional architecture of a cohort of spinal cord DMG patients, we conducted whole-exome sequencing and single-cell RNA sequencing on 19 tumor samples from 7 patients. We identified previously underappreciated stem-like cells associated with hypoxia in malignant tumor cells, which were present in all samples of spinal cord DMG but absent in published intracranial DMG, corroborating cellular heterogeneity based on tumor location. We discovered that tumor-associated myeloid cells constituted the largest population of non-malignant cells in adult spinal cord DMG. Our research revealed a transition from microglia to macrophages, characterized by enhanced cell-to-cell interactions mediated through the VEGF signaling pathway network. Notably, we found that epigenetic agents can repress the expression of hypoxia-related gene programs in patient-derived spinal cord DMG cultures and inhibit cell proliferation in vitro. Collectively, our study reveals a crucial anatomical dimension that DMG exhibits a location-specific genomic and transcriptional landscape despite shared H3K27 alterations, providing the paradigm for developing precision therapeutic strategies that extend beyond DMG to other molecularly defined yet anatomically divergent malignancies.

cancer biology↗

bioRxiv2025

Characterization of PROTAC specificity and endogenous protein interactomes using ProtacID

Here we describe ProtacID, a flexible BioID (proximity-dependent biotinylation)-based approach to identify PROTAC-proximal proteins in living cells. ProtacID analysis of VHL- and CRBN-recruiting PROTACs targeting a number of different proteins (localized to chromatin or cellular membranes, and tested across six different human cell lines) demonstrates how this technique can be used to validate PROTAC degradation targets and identify non-productive (i.e. non-degraded) PROTAC-interacting proteins, addressing a critical need in the field of PROTAC development. We also demonstrate that ProtacID can be used to characterize native, endogenous multiprotein complexes without the use of antibodies, or modification of the protein of interest with epitope tags or biotin ligase tagging.

molecular biology↗

bioRxiv2024

Design and immunogenicity of an HIV-1 clade C pediatric envelope glycoprotein stabilized by multiple platforms

Various design platforms are available to stabilize soluble HIV-1 envelope (Env) trimers, which can be used as antigenic baits and vaccine antigens. However, stabilizing HIV-1 clade C trimers can be challenging. Here, we stabilized an HIV-1 clade C trimer based on an Env isolated from a pediatric elite-neutralizer (AIIMS_329) using multiple platforms, including SOSIP.v8.2, ferritin nanoparticles (NP) and an I53-50 two-component NP, followed by characterization of their biophysical, antigenic, and immunogenic properties. The stabilized 329 Envs showed binding affinity to trimer-specific HIV-1 broadly neutralizing antibodies (bnAbs), with negligible binding to non-neutralizing antibodies (non-nAbs). Negative-stain electron microscopy (nsEM) confirmed the native-like conformation of the Envs. Multimerization of 329 SOSIP.v8.2 on ferritin and two-component I53-50 NPs improved the overall affinity to HIV-1 bnAbs and immunogenicity in rabbits. These stabilized HIV-1 clade C 329 Envs demonstrate the potential to be used as antigenic baits and as components of multivalent vaccine candidates in future.

immunology↗

bioRxiv2024

The progression of infiltrating neurovascular features and chemokine production of the caudal intervertebral disc following injury

Inflammatory cytokine production and de novo neurovascularization have been identified in painful, degenerated intervertebral discs (IVDs). However, the temporal trajectories of these key pathoanatomical features, including the cascade of inflammatory chemokines and neo-vessel and neurite infiltration, and their associations with IVD degeneration, remain relatively unknown. Investigating this process in the caudal mouse IVD enables the opportunity to study the tissue-specific response without confounding inflammatory signaling from neighboring structures. Thus this study aims to define the progression of chemokine production and neurovascular invasion during the IVD degeneration initiated by injury in the caudal spine 3-month-old C57BL6/J mice. Forty-nine IVD-secreted chemokines and matrix metalloproteinases (MMPs) was measured using multiplex ELISA, and the intradiscal infiltrating vessels (endomucin) and nerves (protein-gene-product 9.5) was quantified in the tissue volume using immunohistochemistry. Injury provoked the increase secretion of IL6, CCL2, CCL12, CCL17, CCL20, CCL21, CCL22, CXCL2 and MMP2 proteins. The centrality and structure of inflammatory networks in IVDs evolved over the 12 post-injury weeks, highlighting distinct responses between the acute and chronic phases. Neurites propagated rapidly within 2-weeks post-injury and remained relatively constant until 12-weeks. Vascular vessel length was observed to peak at 4-weeks post-injury and it regressed by 12-weeks. These findings identified the temporal flux of inflammatory chemokines and pain-associated pathoanatomy in a model of IVD degeneration using the mouse caudal spine.

bioengineering↗

bioRxiv2024

IGF-1 Peptide Mimetic-functionalized Hydrogels Enhance MSC Survival and Immunomodulatory Activity

Human mesenchymal stem cells (MSCs) have demonstrated promise when delivered to damaged tissue or tissue defects for their cytokine secretion and inflammation modulation behaviors that can promote repair. Insulin-like growth factor 1 (IGF-1) has been shown to augment MSCs viability and survival and promote their secretion of cytokines that signal to endogenous cells, in the treatment of myocardial infarction, wound healing, and age-related diseases. Biomaterial cell carriers can be functionalized with growth factor-mimetic peptides (i.e. IGF-1 mimicking peptides) to enhance MSC function while promoting cell retention and minimizing off-target effects seen with direct administration of soluble growth factors. Here, we functionalized alginate hydrogels with three distinct IGF-1 peptide mimetics and the integrin-binding peptide, cyclic RGD. One IGF-1 peptide mimetic (IGM-3) in combination with integrin ligand was found to activate Akt and ERK1/2 signaling and support survival of serum-deprived MSCs. MSCs encapsulated in alginate hydrogels that presented both IGM-3 and cRGD showed a significant reduction in pro-inflammatory cytokine secretion when challenged with interleukin-1{beta}. Finally, MSCs cultured within the cRGD/IGM-3 hydrogels were able to blunt pro-inflammatory gene expression of human primary cells from degenerated intervertebral discs. These studies indicate the potential to leverage cell adhesive and IGF-1 growth factor peptide mimetics together to control therapeutic secretory behavior of MSCs. Significance StatementInsulin-like growth factor 1 (IGF-1) plays a multifaceted role in stem cell biology and may promote proliferation, survival, migration, and immunomodulation for MSCs. In this study, we functionalized alginate hydrogels with integrin-binding and IGF-1 peptide mimetics to investigate their impact on MSC function. Encapsulating MSCs in the dual peptide (cRGD/IGM-3) hydrogels enhanced their ability to reduce inflammatory cytokine production and promote anti-inflammatory gene expression in cells from degenerative human intervertebral discs exposed to proteins secreted by the MSC. This approach suggests a new way to retain and augment MSC functionality using IGF-1 peptide mimetics, offering an alternative to co-delivery of cells and high dose soluble growth factors for tissue repair and immune-system modulation.

bioengineering↗

bioRxiv2023

Thermo-Responsive Polymers Targeting Inflammation in Murine Colitis

Targeting the site of inflammation is an ideal approach for treating inflammatory bowel disease (IBD). Inflammation targeting enables maximal drug-on-target effects while minimizing off-target side effects. Negatively charged drug carriers have been shown to facilitate drug delivery to inflamed colon mucosa after local administration. To modulate the negative charges and integrate responsiveness to stimuli, here we describe thermo-responsive, inflammation-targeting (TRIT) hydrogels based on functionalized poly(N-isopropylacrylamide-co-methacrylic acid) (PNIPAM-MAA). We show that both chemical modification types and polymer molecular weights affect the resultant microgels adhesion to the inflamed colon in dextran sulfate sodium (DSS)-induced murine colitis in vivo. Further, we quantified the correlations between microgels adhesion and colitis severity for individual mice, demonstrating that the microgels adhesion correlated directly with weight loss percentage in DSS-treated mice. By exploiting charge-mediated interaction and thermo-responsiveness, TRIT hydrogels represent a promising strategy to target inflamed colon mucosa as a drug delivery platform for colonic IBD treatment. TeaserThis study developed thermo-responsive, inflammation-targeting (TRIT) hydrogels that harness charge-mediated interaction and sol-to-gel transition to target inflamed colon mucosa as a new approach for treating inflammatory bowel disease.

bioengineering↗

bioRxiv2023

Epigenetic Reshaping through Damage: Promoting Cell Fate Transition by BrdU and IdU Incorporation

Thymidine analogs have long been recognized for their ability to randomly incorporate into DNA. However, their significance in the chemical induction of pluripotency (CIP) remains unclear. Here, we investigated the impact of BrdU/IdU incorporation on the transition of cell fate through DNA damage repair (DDR). Our findings reveal a substantial upregulation of reprogramming mediator gene H3K27ac and H3K9ac, as well as global DNA demethylation in response to DDR. This process creates a hypomethylated environment that promotes cell fate transition. We term this mechanism as Epigenetic Reshaping through Damage (ERD). Overall, our study sheds light on the dynamic interplay between thymidine analogs, DDR, and epigenetic modifications, providing valuable insights into the mechanisms underlying cell fate transition.

cell biology↗

bioRxiv2023

Multi-species polyploidization, chromosome shuffling, and genome extraction in Zea/Tripsacum hybrids

By hybridization and special sexual reproduction, we sequentially aggregated Zea mays, Zea perennis, and Tripsacum dactyloides in an allohexaploid, backcrossed it with maize, derived self-fertile allotetraploids of maize and Z. perennis by natural genome extraction, extended their first six selfed generations, and finally constructed amphitetraploid maize using nascent allotetraploids as a genetic bridge. Transgenerational chromosome inheritance, subgenomes stability, chromosome pairings and rearrangements, and their impacts on an organisms fitness were investigated by fertility phenotyping and molecular cytogenetics techniques GISH and FISH. Results showed that diversified sexual reproductive methods produced highly differentiated progenies (2n=35-84) with varying proportions of subgenomic chromosomes, of which one individual (2n=54, MMMPT) overcame self-incompatibility barriers and produced self-fertile nascent near-allotetraploid by preferentially eliminating Tripsacum chromosomes. Nascent near-allotetraploid progenies showed persistent chromosome changes, intergenomic translocations, and rDNA variations for at least up to the first six selfed generations; however, ploidy tended to stabilize at near-tetraploid level (2n=40) with full integrity of 45SrDNA pairs, and a trend of decreasing variations by advancing generations with an average of 25.53, 14.14, and 0.37 maize, Z. perennis, and T. dactyloides chromosomes, respectively. The mechanisms for three genome stabilities and karyotype evolution for formatting new polyploid species were discussed.

genetics↗

bioRxiv2022

Single Cell RNA-Sequence Analyses Reveal Uniquely Expressed Genes and Heterogeneous Immune Cell Involvement in the Rat Model of Intervertebral Disc Degeneration

Intervertebral disc (IVD) degeneration is characterized by a loss of cellularity, and changes in cell-mediated activity that drives anatomic changes to IVD structure. In this study, we use single cell RNA-sequencing analysis of cells extracted from the degenerating tissues of the rat IVD following lumbar disc puncture. Two control, uninjured IVDs (L2-3, L3-4) and two degenerated, injured IVDs (L4-5, L5-6) from each animal were examined either at two- and eight-week post-operative time points. The cells from these IVDs were extracted and transcriptionally profiled at a single-cell resolution. Unsupervised cluster analysis revealed the presence of 4 known cell types in both non-degenerative and degenerated IVDs based on previously established gene markers: IVD cells, endothelial cells, myeloid cells, and lymphoid cells. As a majority of cells were associated with the IVD cell cluster, sub-clustering was used to further identify the cell populations of the nucleus pulposus, inner and outer annulus fibrosus. The most notable difference between control and degenerated IVDs was the increase of myeloid and lymphoid cells in degenerated samples at 2- and 8- weeks post-surgery. Differential gene expression analysis revealed multiple distinct cell types from the myeloid and lymphoid lineages, most notably macrophages and B lymphocytes and demonstrated a high degree of immune specificity during degeneration. In addition to the heterogenous infiltrating immune cell populations in the degenerating IVD, the increased number of cells in the AF sub-cluster expressing Ngf and Ngfr, encoding for p75NTR, suggest that NGF signaling may be one of the key mediators of the IVD crosstalk between immune and neuronal cell populations. These findings provide the basis for future work to understand the involvement of select subsets of non-resident cells in IVD degeneration.

cell biology↗

bioRxiv2021

Engineered Peptide-Functionalized Hydrogels Modulate the RNA Transcriptome of Human Nucleus Pulposus Cells In Vitro

Degeneration and aging of the nucleus pulposus (NP) of the intervertebral disc (IVD) is accompanied by alterations in NP cell phenotype marked by a shift towards a fibroblast-like, catabolic state. We have recently demonstrated an ability to manipulate the phenotype of human adult degenerative NP cells through 2D culture upon poly(ethylene glycol) (PEG) based hydrogels dually functionalized with integrin- and syndecan-binding laminin-mimetic peptides (LMPs). In the present study, we sought to understand the transcriptomic changes elicited through NP cell interactions with the LMP-functionalized hydrogel system (LMP gel) by examining targets of interest a priori and by conducting unbiased analysis to identify novel mechanosensitive targets. The results of gene specific analysis demonstrated that the LMP gel promoted adult degenerative NP cells to upregulate 148 genes including several NP markers (e.g. NOG and ITGA6) and downregulate 277 genes, namely several known fibroblastic markers. Additionally, 13 genes associated with G protein-coupled receptors, many of which are known drug targets, were identified as differentially regulated following culture upon the gel. Furthermore, through gene set enrichment analysis we identified over 700 pathways enriched amongst the up- and downregulated genes including pathways related to cell differentiation, notochord morphogenesis, and intracellular signaling. Together these findings demonstrate the global mechanobiological effects induced by the LMP gel and confirm the ability of this substrate to modulate NP cell phenotype.

cell biology↗

bioRxiv2020

CD4 and CD8 co-receptors modulate functional avidity of CD1b-restricted T cells.

CD4 and CD8 co-receptors define distinct lineages of T cells restricted by major histocompatibility complex (MHC) Class II and I molecules, respectively. Co-receptors interact with the T cell receptor (TCR) at the surface of MHC-restricted T cells to facilitate antigen recognition, thymic selection, and functional differentiation. T cells also recognize lipid antigens presented by CD1 molecules, but the role that CD4 and CD8 play in lipid antigen recognition is unknown. We studied the effect of CD4 and CD8 on the avidity, activation, and function of T cells specific for two CD1b-presented mycobacterial lipid antigens, glucose monomycolate (GMM) and diacylated sulfoglycolipids (SGL). In a human cohort study using SGL-loaded CD1b tetramers, we discovered a hierarchy among SGL-specific T cells in which T cells expressing the CD4 or CD8 co-receptor stain with a higher tetramer mean fluorescence intensity (MFI) than CD4-CD8- T cells. To determine the role of the TCR co-receptor in lipid antigen recognition, we exogenously expressed GMM and SGL-specific TCRs in Jurkat or polyclonal T cells and quantified tetramer staining and activation thresholds. Transduced CD4+ primary T cells bound the lipid-loaded CD1b tetramer with a higher MFI than CD8+ primary T cells, and transduced CD8+ Jurkat cells bound the SGL-CD1b tetramer with higher MFI than CD4-CD8- Jurkat cells. The presence of either co-receptor also decreased the threshold for IFN-{gamma} secretion. Further, co-receptor expression increased surface expression of CD3{varepsilon}, suggesting a mechanism for increased tetramer binding and activation. Finally, we used single-cell sequencing to define the TCR repertoire and ex vivo functional profiles of SGL-specific T cells from individuals with M.tb disease. We found that CD8+ T cells specific for SGL express canonical markers associated with cytotoxic T lymphocytes, while CD4+ T cells could be classified as T regulatory or T follicular helper cells. Among SGL-specific T cells, only those expressing the CD4 co-receptor also expressed Ki67, suggesting that they were actively proliferating at the time of sample collection. Together, these data reveal that expression of CD4 and CD8 co-receptor modulates TCR avidity for lipid antigen, leading to functional diversity and differences in in vivo proliferation during M.tb disease.

immunology↗

bioRxiv2019

Synergism of gut microbiota to double-stranded RNAs in RNA interference of a leaf beetle

RNA interference (RNAi) has emerged as an efficient tool to control insect pests. When lethal double-stranded RNAs (dsRNAs) were ingested by the insects, strong gene silencing and mortality can be induced. To exert their function, dsRNA molecules must pass through insects gut and enter epithelial cells and/or the hemolymph. Gut bacteria are known to inhabit on the epithelial surface to confer host new capabilities to counter both biotic and abiotic stress. Whether there is a crosstalk between gut bacteria and dsRNAs and the effects of the microbiome on RNAi efficiency remains unknown. Here, using a leaf beetle-gut microbiota system, we investigated whether and how gut bacteria interact with dsRNA molecules and its effects on host insects. We firstly showed that the leaf beetle Plagiodera versicolora (Coleoptera) is highly susceptible to RNAi. Then, we found that ingestion of dsRNAs by non-axenic P. versicolora larvae results in (i) significantly accelerated mortality compared to axenic larvae, and (ii) over-growth and dysbiosis of the gut microbiota. The latter is mainly caused by the bacterial utilization of the dsRNA degraded products initiated by the host insect. Furthermore, we found that Pseudomonas putida, a gut bacterium of P. versicolora, was a main commensal-to-pathogen strain that accelerated the death of P. versicolora larvae. Taken together, our findings reveal a synergistic role of gut microbiota to dsRNA-induced mortality of pest insects, which provides new insights in the ecological functions of insect gut bacteria, and also contributes to a better understanding of the RNAi mechanisms in insects.

ecology↗