Biology subjects

Tu, L.

Publications and source records attributed to Tu, L..

11 recordsLinked to original sources

bioRxiv2026

Paternal behavior is controlled by preoptic Trpc5 neurons

Male parenting behavior is highly conserved and activated only after offspring are born. Here we show that the behavioral switch from infanticide in virgin male mice to caregiving in wild-type sires is associated with enhanced expression and activation of Transient receptor potential channel 5 (Trpc5) in estrogen receptor (Esr1)-expressing neurons in the hypothalamic medial preoptic area (MPOA). While selective deletion of Trpc5 from Esr1MPOA neurons diminishes paternal behavior in sires, overexpression of Trpc5 in these neurons converts the otherwise infanticidal virgin males to exhibit care to pups. Mechanistically, Trpc5-dependent changes in neuronal excitability underlie fatherhood-associated Esr1MPOA neuron plasticity. Notably, Trpc5 overexpression also enhances escape behavior and elicits exploratory diving behavior, suggesting that these neurons control a broader adaptive parenting response in males. These findings establish a Trpc5-dependent MPOA neural signal as a critical regulator of paternal behavior.

neuroscience↗

bioRxiv2026

THIK-1 channel mediates microglial glucose sensing and modulates AgRP neurons

Microglia play essential roles in maintaining energy homeostasis, and their dysfunction contributes to metabolic disease. Although high-fat diet (HFD) exposure induces microglial activation, the underlying mechanisms remain poorly defined. Here, we identified a previously unrecognized role for THIK-1 channel in mediating glucose sensing of microglia in arcuate nucleus of the hypothalamus (ARH), during HFD-induced obesity. Pharmacological inhibition of THIK-1 channel with tetrapentylammonium (TPA) suppresses feeding and attenuates body-weight gain in diet induced obese mice. Mechanistically, inhibition of agouti-related peptide (AgRP) neurons is indispensable for TPA-induced hypophagia. Moreover, THIK-1 inhibition promotes microglial phagocytosis of perineuronal nets (PNNs), leading to reduced AgRP neuronal activity and feeding suppression. Together, these findings establish THIK-1 as a critical glucose sensor in hypothalamic microglia and uncover a microglia-dependent pathway through which overnutrition modulates AgRP neuronal activity via PNN remodeling to regulate energy balance, highlighting THIK-1 as a potential therapeutic target for treatment of diet-induced obesity.

neuroscience↗

bioRxiv2025

Early-stage determinants of T1-S1 conformations in Kv1.3 channels

Early-stage biogenesis of voltage-gated potassium channels (Kv) remains remarkably understudied yet is key to defining co- and post-translational acquisition of Kv secondary, tertiary, and quaternary conformations. Thus, we have studied nascent folding events and their determinants in Kv1.3, a tetrameric ion channel highly expressed in nerve and immune cells. We explore how folding of T1, an intersubunit recognition domain that ensures correct isoform assembly, is modulated by molecular determinants in the Kv subunit. Specifically, we focus on the T1-S1 linker and its highly conserved C-terminal sequence, S0. Using pegylation, a mass-tagging strategy, inter- and intrasubunit crosslinking, we define the molecular determinants of T1-S1 linker accessibility and location. Our findings show that i) dynamic protein-lipid and protein-protein linker interfaces exist, ii) the presence of a T1 domain and its conformation (monomer versus tetramer) impact linker properties, iii) helical formation of S0 occurs in early biogenic stages and does not require the presence of membranes, iv) a core recognition domain (T2) increases T1 dimerization efficiency and promotes tetramer formation, and v) as few as 12 native linker residues enable T1 tetramerization. These findings differ from canonical models and suggest that domain plasticity for Kv1.3 contributes to biogenesis and may underlie domain-domain communication in Kv function.

physiology↗

bioRxiv2024

5-HT Neurons Integrate GABA and Dopamine Inputs to Regulate Meal Initiation

Obesity is a growing global health epidemic with limited effective therapeutics. Serotonin (5-HT) is one major neurotransmitter which remains an excellent target for new weight-loss therapies, but there remains a gap in knowledge on the mechanisms involved in 5-HT produced in the dorsal Raphe nucleus (DRN) and its involvement in meal initiation. Using a closed-loop optogenetic feeding paradigm, we showed that the 5-HTDRN{lozenge}arcuate nucleus (ARH) circuit plays an important role in regulating meal initiation. Incorporating electrophysiology and ChannelRhodopsin-2-Assisted Circuit Mapping, we demonstrated that 5-HTDRN neurons receive inhibitory input partially from GABAergic neurons in the DRN, and the 5-HT response to GABAergic inputs can be enhanced by hunger. Additionally, deletion of the GABAA receptor subunit in 5-HT neurons inhibits meal initiation with no effect on the satiation process. Finally, we identified the instrumental role of dopaminergic inputs via dopamine receptor D2 in 5-HTDRN neurons in enhancing the response to GABA-induced feeding. Thus, our results indicate that 5-HTDRN neurons are inhibited by synergistic inhibitory actions of GABA and dopamine, which allows for the initiation of a meal.

neuroscience↗

bioRxiv2021

A human monoclonal antibody potently pan-neutralizes SARS-CoV-2 VOCs by targeting RBD invariant sites

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global pandemic of novel corona virus disease (COVID-19). The neutralizing monoclonal antibodies (mAbs) targeting the receptor binding domain (RBD) of SARS-CoV-2 are among the most promising strategies to prevent and treat COVID-19. However, SARS-CoV-2 variants of concern (VOCs) profoundly reduced the efficacies of most of mAbs and vaccines approved for clinical use. Herein, we demonstrated mAb 35B5 efficiently neutralizes both wild-type (WT) SARS-CoV-2 and VOCs, including B.1.617.2 (delta) variant, in vitro and in vivo. Cryo-electron microscopy (cryo-EM) revealed that 35B5 neutralizes SARS-CoV-2 by targeting a unique epitope that avoids the prevailing mutation sites on RBD identified in circulating VOCs, providing the molecular basis for its pan-neutralizing efficacy. The 35B5-binding epitope could also be exploited for the rational design of a universal SARS-CoV-2 vaccine.

immunology↗

bioRxiv2021

microRNA Expression Levels Change in Neonatal Patients During and After Exposure to Cardiopulmonary Bypass

ObjectivesThe systemic inflammation that occurs after exposure to cardiopulmonary bypass (CPB), which is especially severe in neonatal patients, is associated with poorer outcomes and is not well understood. In order to gain deeper insight into how exposure to bypass activates inflammatory responses in circulating leukocytes, we studied changes in microRNA (miRNA) expression during and after exposure to bypass. miRNAs are small non-coding RNAs that have important roles in modulating protein levels and function of cells. MethodsWe performed miRNA-Sequencing on leukocytes isolated from neonatal cardiopulmonary bypass patients (N=5) at 7 timepoints during the process of CPB, including prior to the initiation of bypass, during bypass, and at three time points during the first 24 hours after weaning from bypass. We identified significant differentially expressed miRNAs using generalized linear regression models, and miRNAs were defined as statistically significant using an FDR adjusted p <0.05. We identified gene targets of these miRNAs using the Targetscan database, and identified significantly enriched biological pathways for these gene targets. ResultsWe identified 54 miRNAs with differential expression during and after CPB. These miRNAs clustered into 3 groups, including miRNAs that were increased during and after CPB (3 miRNAs), miRNAs that decreased during and after CPB (10 miRNAs), and miRNAs that decreased during CPB but then increased 8-24 hours after CPB. 38.9% of the target genes of these miRNAs were significantly differentially expressed in our previous study. miRNAs with altered expression levels are predicted to significantly modulate pathways related to inflammation and signal transduction. ConclusionsThe unbiased profiling of the miRNA changes that occur in the circulating leukocytes of bypass patients provides deeper insight into the mechanisms that underpin the systemic inflammatory response that occurs in patients after exposure to cardiopulmonary bypass. These data will help the development of novel treatments and biomarkers for bypass associated inflammation.

developmental biology↗

bioRxiv2021

Hypothalamic perineuronal nets are regulated by sex and dietary interventions

Perineuronal nets (PNNs) are widely present in the hypothalamus, and are thought to provide physical protection and ion buffering for neurons, and regulate their synaptic plasticity and intracellular signaling. Recent evidence indicates that PNNs in the mediobasal hypothalamus plays an important role in the regulation of glucose homeostasis. However, whether and how hypothalamic PNNs are regulated are not fully understood. In the present study, we examined whether PNNs in various hypothalamic regions in mice can be regulated by sex, gonadal hormones, dietary interventions, or their interactions. We demonstrated that gonadal hormones are required to maintain normal PNNs in the arcuate nucleus of hypothalamus in both male and female mice. In addition, PNNs in the terete hypothalamic nucleus display a sexual dimorphism with females higher than males, and high-fat diet feeding increases terete PNNs only in female mice but not in male mice. On the other hand, PNNs in other hypothalamic regions are not influenced by sex, gonadal hormones or dietary interventions. In summary, we demonstrated that hypothalamic PNNs are regulated in a region-specific manner and these results provide a framework to further investigate the potential functions of PNNs in regulating energy/glucose homeostasis at the interplay of sex, gonadal hormones and diets.

neuroscience↗

bioRxiv2021

TAK1: a potential therapeutic target for retinal neovascularization

Retinal neovascularization, or pathological angiogenesis in the retina, is a leading cause of blindness in developed countries. Transforming growth factor-{beta}-activated kinase 1 (TAK1) is a mitogen-activated protein kinase kinase kinase (MAPKKK) activated by TGF-{beta}1 and other pro-inflammatory cytokines. TAK1 is also a key mediator of inflammation, innate immune responses, apoptosis and tissue homeostasis and plays an important role in physiological angiogenesis. Its role in pathological angiogenesis, particularly in retinal neovascularization, remains unclear. We investigated the regulatory role of TAK1 in pathological angiogenesis in the retina. Transcriptome analysis of human retina featuring retinal neovascularization revealed enrichment of known TAK1-mediated signaling pathways. Selective inhibition of TAK1 activation by 5Z-7-oxozeaenol attenuated aberrant retinal angiogenesis in rats following oxygen-induced retinopathy. Transcriptome profiling revealed that TAK1 activation in human microvascular endothelial cells under TNF stimulation led to increase the gene expression related to cytokines and leukocyte-endothelial interaction, mainly through nuclear factor kappa B (NF{kappa}B) signaling pathways. These results reveal that inhibition of TAK1 signaling may have therapeutic value for the treatment of pathological angiogenesis in the retina.

biochemistry↗

bioRxiv2020

Predicting heterogeneity in clone-specific therapeutic vulnerabilities using single-cell transcriptomic signatures

While understanding heterogeneity in molecular signatures across patients underpins precision oncology, there is increasing appreciation for taking intra-tumor heterogeneity into account. Single-cell RNA-seq (scRNA-seq) technologies have facilitated investigations into the role of intra-tumor transcriptomic heterogeneity (ITTH) in tumor biology and evolution, but their application to in silico models of drug response has not been explored. Based on large-scale analysis of cancer omics datasets, we highlight the utility of ITTH for predicting clinical outcomes. We then show that heterogeneous gene expression signatures obtained from scRNA-seq data can be accurately analyzed (80%) in a recommender system framework (CaDRReS-Sc) for in silico drug response prediction. Patient-derived cell lines capturing transcriptomic heterogeneity from primary and metastatic tumors were used as in vitro proxies for validating monotherapy predictions (Pearson r>0.6), as well as optimal drug combinations to target different subclonal populations (>10% improvement). Applying CaDRReS-Sc to the increasing number of publicly available tumor scRNA-seq datasets can serve as an in silico screen for further in vitro and in vivo drug repurposing studies. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=191 SRC="FIGDIR/small/389676v1_ufig1.gif" ALT="Figure 1"> View larger version (32K): org.highwire.dtl.DTLVardef@1aa5795org.highwire.dtl.DTLVardef@5c2323org.highwire.dtl.DTLVardef@106e074org.highwire.dtl.DTLVardef@7a0834_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LILarge-scale analysis to establish the impact of transcriptomic heterogeneity within tumors on clinical outcomes C_LIO_LICalibrated recommender system for drug response prediction based on single-cell RNA-seq data (CaDRReS-Sc) C_LIO_LIPrediction of drug response in patient-derived cell lines with transcriptomic heterogeneity C_LIO_LIIn silico identification of drug combinations that work based on clonal vulnerabilities C_LI

bioinformatics↗

bioRxiv2019

MicroRNA-143 plays a protective role in ischemia-induced retinal neovascularization

Retinal neovascularization is a severe complication of proliferative diabetic retinopathy. MicroRNAs (miRNAs) are master regulators of gene expression that play important roles in retinal neovascularization. Here, we investigated the retinal miRNA expression profile in a rat model of oxygen-induced retinopathy (OIR) through miRNA-Seq. We found that miR-143-3p, miR-126-3p, miR-150-5p and miR-145-5p were significantly down-regulated in the retina of OIR rats, and directly involved in the development of retinal neovascularization. Of these identified miRNAs, miR-143 is enriched in retina and was first reported being associated with pathological retinal angiogenesis. Our RNA-Seq data further suggested that miR-143 alleviates retinal neovascularization by mediating the inflammation/stress pathways via Fos. Moreover, the computational analysis indicated that Transforming Growth Factor-beta Activated Kinase 1 (TAK1) is involved in several key pathways associated with the dysregulated miRNAs. The pharmacological inhibition of TAK1 suppressed angiogenesis in vitro and retinal neovascularization in vivo. Our data highlight the utility of next-generation sequencing in the development of therapeutics for ocular neovascularization and further suggest that therapeutic targeting the dysregulated miRNAs or TAK1 may be a feasible adjunct therapeutic approach in patients with retinal neovascularization.

molecular biology↗

bioRxiv2018

Efficacy and dynamics of self-targeting CRISPR/Cas constructs for gene editing in the retina.

Safe delivery of CRISPR/Cas endonucleases remains one of the major barriers to the widespread application of in vivo genome editing including the anticipatory treatment of monogenic retinal diseases. We previously reported the utility of adeno-associated virus (AAV)-mediated CRISPR/Cas genome editing in the retina; however, with this type of viral delivery system, active endonucleases will remain in the retina for an extended period, making genotoxicity a significant consideration in clinical applications. To address this issue, we have designed a self-destructing \"kamikaze\" CRISPR/Cas system that disrupts the Cas enzyme itself following expression. Four guide RNAs (sgRNAs) were designed to target Streptococcus pyogenes Cas9 (SpCas9), after in situ validation, the selected sgRNAs were cloned into a dual AAV vector. One construct was used to deliver SpCas9 and the other delivered sgRNAs directed against SpCas9 and the target locus (yellow fluorescent protein, YFP), in the presence of mCherry. Both constructs were packaged into AAV2 vector and intravitreally administered in C57BL/6 and Thy1-YFP transgenic mice. After 8 weeks the expression of SpCas9, the efficacy of YFP gene disruption was quantified. A reduction of SpCas9 mRNA was found in retinas treated with AAV2-mediated-YFP/SpCas9 targeting CRISPR/Cas compared to those treated with YFP targeting CRISPR/Cas alone. We also show that AAV2-mediated delivery of YFP/SpCas9 targeting CRISPR/Cas significantly reduced the number of YFP fluorescent cells among mCherry-expressing cells (~85.5% reduction compared to LacZ/SpCas9 targeting CRISPR/Cas) in transfected retina of Thy1-YFP transgenic mice. In conclusion, our data suggest that a self-destructive \"kamikaze\" CRISPR/Cas system can be used as a robust tool for refined genome editing in the retina, without compromising on-target efficiency.

genetics↗