Biology subjects

Wang, Q.

Publications and source records attributed to Wang, Q..

At least 289 records · Page 16Linked to original sources

bioRxiv2024

A biodegradable and restorative peripheral neural interface for the interrogation of neuropathic injuries

Monitoring the early-stage healing of severe traumatic nerve injuries is essential to gather physiological and pathological information for timely interventions and optimal clinical outcomes. While implantable peripheral nerve interfaces provide direct access to nerve fibers for precise interrogation and modulation, conventional non-degradable designs pose limited utilization in nerve injury rehabilitation. Here, we introduce a biodegradable and restorative neural interface for wireless real-time tracking and recovery of long-gap nerve injuries. Leveraging machine learning techniques, this electronic platform deciphers nerve recovery status and identifies traumatic neuroma formation at the early phase, enabling timely intervention and significantly improved therapeutic outcomes. The biodegradable nature of the device eliminates the need for retrieval procedures, reducing infection risks and secondary tissue damage. This research sheds light on bioresorbable multifunctional peripheral nerve interfaces for probing neuropathic injuries, offering vital information for early diagnosis and therapeutic intervention.

bioengineering↗

bioRxiv2024

The effect of norepinephrine on ovarian dysfunction by mediating ferroptosis in mice model

Studies shows that stress is associated with ovarian dysfunction. Norepinephrine (NE), a classic stress hormone in the stress response, is less recognized for its role in ovarian function. A NE-treated mouse model is induced by intraperitoneal injection of NE for 4 weeks. Compared with the normal control, we find that NE-treated mice show disturbances in the estrous cycle, decreased levels of anti-Mullerian hormone (AMH) and estradiol (E2), and increased levels of follicle-stimulating hormone (FSH). Additionally, the number of primordial follicles, primary follicles, secondary follicles, and antral follicles decreased, while the number of atretic follicles increased in NE-treated mice, indicating NE-induced ovarian dysfunction. RNA sequencing further reveals that genes associated with ferroptosis are significantly enriched in NE-treated ovarian tissues. Concurrently, the content of reactive oxygen species (ROS), ferrous ion, and malondialdehyde (MDA) increased, while the expression level of glutathione peroxidase 4 (GPX4) decreased. To elucidate the mechanism of NE-induced ferroptosis in ovaries and the potential reversal by Coenzyme Q10 (CoQ10), an antioxidant, we conduct both in vitro and in vivo experiments. In vitro, we observe that the granulosa cell line KGN, when treated with NE, shows decreased cell viability, reduced expression of GPX4, elevated ferrous ion and ROS content, and increased MDA levels. However, these NE-induced changes are rescued by the addition of CoQ10. In the mouse model, we find that NE-treated mice supplemented with CoQ10 increased GPX4 levels and decreased the contents of iron, ROS, and MDA compared with the NE group. Moreover, the differential expression of genes associated with ferroptosis induced by NE is ameliorated by CoQ10 in NE-treated mice. Additionally, CoQ10 improved ovarian function, as evidenced by increased ovarian weight, more regular estrous cycles, and an increase in follicles at various stages of growth in NE-treated mice. In conclusion, NE induces ovarian dysfunction by triggering ferroptosis in ovarian tissues, and CoQ10 represents a promising approach for protecting reproductive function by inhibiting ferroptosis.

molecular biology↗

bioRxiv2024

DNA damage response signatures are associated with frontline chemotherapy response and routes of tumor evolution in extensive stage small cell lung cancer

IntroductionA hallmark of small cell lung cancer (SCLC) is its recalcitrance to therapy. While most SCLCs respond to frontline therapy, resistance inevitably develops. Identifying phenotypes potentiating chemoresistance and immune evasion is a crucial unmet need. Previous reports have linked upregulation of the DNA damage response (DDR) machinery to chemoresistance and immune evasion across cancers. However, it is unknown if SCLCs exhibit distinct DDR phenotypes. MethodsTo study SCLC DDR phenotypes, we developed a new DDR gene analysis method and applied it to SCLC clinical samples, in vitro, and in vivo model systems. We then investigated how DDR regulation is associated with SCLC biology, chemotherapy response, and tumor evolution following therapy. ResultsUsing multi-omic profiling, we demonstrate that SCLC tumors cluster into three DDR phenotypes with unique molecular features. Hallmarks of these DDR clusters include differential expression of DNA repair genes, increased replication stress, and heightened G2/M cell cycle arrest. SCLCs with elevated DDR phenotypes exhibit increased neuroendocrine features and decreased "inflamed" biomarkers, both within and across SCLC subtypes. Treatment naive DDR status identified SCLC patients with different responses to frontline chemotherapy. Tumors with initial DDR Intermediate and DDR High phenotypes demonstrated greater tendency for subtype switching and emergence of heterogeneous phenotypes following treatment. ConclusionsWe establish that SCLC can be classified into one of three distinct, clinically relevant DDR clusters. Our data demonstrates that DDR status plays a key role in shaping SCLC phenotypes, chemotherapy response, and patterns of tumor evolution. Future work targeting DDR specific phenotypes will be instrumental in improving patient outcomes.

cancer biology↗

bioRxiv2024

CIB2 as a Ca2+ Sensor for Auditory Mechano-Electrical Transduction and Linked to Genetic-Heterogeneity of TMC1 in Hearing Loss

Non-syndromic sensorineural hearing loss is characterized by genetic heterogeneity, leading to potential clinical misdiagnosis. TMC1, a unique causative gene associated with deafness, exhibits variants with autosomal dominant and recessive inheritance patterns. TMC1 codes for the transmembrane channel-like 1 (TMC1), a key component of the mechano-electrical transduction (MET) machinery for hearing. However, the molecular mechanism of Ca2+ regulation in MET, which is essential for sound perception, remains unclear. CIB2, another MET component associated with deafness, can bind with calcium and may play a role in MET gating. Our study reveals that the TMC1-CIB2 complex undergoes a Ca2+-induced conformational change, highlighting the crucial role of Ca2+ in MET. We identified a vertebrate-specific binding site on TMC1, named CR3, that interacts with apo CIB2, with the binding interface linked to hearing loss. Using an in-vivo animal model, we demonstrated that disruption of the calcium-sensing site of CIB2 perturbs the MET channel conductivity, confirming its role as a Ca2+ sensor for MET. Additionally, after systematically analyzing the hearing-loss variants, we observed that dominant mutations of TMC1 are often located near the ion pore or at the binding interfaces with the Ca2+ sensor CIB2. This provides a detailed mechanism of the genetic heterogeneity of TMC1 in hearing loss at an atomic level.

molecular biology↗

bioRxiv2024

BCAS2 promotes primitive hematopoiesis by sequestering β-catenin within the nucleus

Breast carcinoma amplified sequence 2 (BCAS2), a core component of the hPrP19 complex, plays crucial roles in various physiological and pathological processes. However, whether BCAS2 has functions other than being a key RNA-splicing regulator within the nucleus remains unknown. Here, we show that BCAS2 is essential for primitive hematopoiesis in zebrafish and mouse embryos. The activation of Wnt/{beta}-catenin signal, which is required for hematopoietic progenitor differentiation, is significantly decreased upon depletion of bcas2 in zebrafish embryos and mouse embryonic fibroblasts (MEFs). Interestingly, BCAS2 deficiency has no obvious impact on the splicing efficiency of {beta}-catenin pre-mRNA, while significantly attenuating {beta}-catenin nuclear accumulation. Moreover, we find that BCAS2 directly binds to {beta}-catenin via its coiled-coil domains, thereby sequestering {beta}-catenin within the nucleus. Thus, our results uncover a previously unknown function of BCAS2 in promoting Wnt signaling by enhancing {beta}-catenin nuclear retention during primitive hematopoiesis.

developmental biology↗

bioRxiv2024

OPUS-BFactor: Predicting protein B-factor with sequence and structure information

Protein B-factor, also known as the Debye-Waller factor, measures the fluctuation of an atom around its average position. It serves as a crucial indicator of protein flexibility and dynamics. However, accurately predicting the B-factor of C atoms remains challenging. In this work, we introduce OPUS-BFactor, a tool for predicting the normalized protein B-factor. OPUS-BFactor operates in two modes: the first mode, OPUS-BFactor-seq, uses sequence information as input, allowing predictions based solely on protein sequence; the second mode, OPUS-BFactor-struct, uses structural information, requiring the 3D structure of the target protein. Evaluation on three test sets, including recently released targets from CAMEO and CASP15, demonstrates that OPUS-BFactor significantly outperforms other B-factor prediction methods. Therefore, OPUS-BFactor is a valuable tool for predicting protein properties related to the B-factor, such as flexibility, thermal stability, and region activity.

bioinformatics↗

bioRxiv2024

HERV-derived epitopes represent new targets for T-cell based immunotherapies in ovarian cancer

BackgroundOvarian cancer represents the most lethal gynecological cancer with poor results of checkpoint inhibitors. Human endogenous retroviruses (HERVs) are aberrantly expressed by tumor cells and may represent a source of shared T cell epitopes for cancer immunotherapy regardless of the tumor mutational burden. MethodsA transcriptomic analysis based on RNA-sequencing (RNA-seq) was developed to quantify the expression of HERV-K sequences containing the selected epitopes. The presence of HERV-K/HML-2 Gag antigen was then assessed by immunohistochemistry (IHC) on tumor microarrays from ovarian cancer samples and normal ovarian tissues. A specific immunopeptidomics approach was developed to detect epitopes on HLA molecules. Epitope-specific CD8+ T cells were quantified by multimer staining and in vitro target cell killing was evaluated using xCELLigence technology. In vivo antitumor efficacy of HERV-specific T cells was assessed in an avian embryo model. ResultsEpitope-containing HERV transcripts were significantly higher in ovarian cancers compared to normal tissues. The presence of HERV-K/HML-2 Gag antigen was confirmed by IHC in 20/40 (50%) ovarian cancers while no Gag expression was found in normal ovarian tissue samples. Immunopeptidomics analysis showed the presence of epitopes on HLA molecules on the surface of ovarian tumor cell lines but not on normal primary cells from critical tissues. HERV-specific T cells were detected among tumor infiltrating lymphocytes (TILs) from ovarian cancers, confirming the immunogenicity of these epitopes in patients. In vitro, HERV-specific T cells specifically killed ovarian cancer cells in an HLA class I-restricted manner while sparing normal HLA-A2-positive primary cells derived from critical tissues. Epitope-specific CD8+ T cells exhibited a strong anti-tumoral activity in vivo, inducing a highly significant decrease in tumor volume in comparison with control groups. ConclusionThese results provide the preclinical rationale for developing T-cell based approaches against HERV-K-derived epitopes in ovarian cancer. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=66 SRC="FIGDIR/small/603392v1_ufig1.gif" ALT="Figure 1"> View larger version (20K): org.highwire.dtl.DTLVardef@1c889b8org.highwire.dtl.DTLVardef@c9b0c5org.highwire.dtl.DTLVardef@1748100org.highwire.dtl.DTLVardef@1c129cc_HPS_FORMAT_FIGEXP M_FIG C_FIG O_LISome HERVs are specifically overexpressed in ovarian cancer compared to normal tissues. C_LIO_LIHERV-K/HML-2 Gag antigen is detected by immunohistochemistry in ovarian cancers but not in normal ovarian tissues. Furthermore, HERV-K-derived epitopes are presented on HLA molecules on the surface of ovarian cancer cells but not on normal cells. C_LIO_LIThese epitopes are immunogenic in patients and induce high-avidity CD8+ T cells that specifically kill ovarian cancer cells in vitro and in vivo while sparing normal cells. C_LI

immunology↗

bioRxiv2024

High-throughput drug screening for inhibition of influenza A virus infection based on human SIRT1 promoter and Genipin suppressing influenza A virus by activation of AMPK-SIRT1-PGC-1α signaling pathway

The energy metabolism crisis is considered an important risk factor for severe influenza A virus (IAV) infection. During virus replication, the host cells "metabolic reprogramming" is beneficial for increasing the energy demand of the virus. SIRT1 plays a major role in altering metabolic reprogramming, and upregulation of SIRT1 expression can defend against viral infection. This study established a high-throughput drug screening method for human SIRT1 promoter. Nine natural medicines were selected from 134 traditional Chinese medicines. Among them, the activity of Gardenia jasminoides Ellis was relatively high. Further research has found that the plant extract and its active compound Genipin and its derivatives can significantly inhibit IAV replication, improve the survival rate of infected mice, and inhibit pneumonia. In addition, Genipin significantly increased the levels of energy metabolism core regulatory factors SIRT1, PPAR {gamma}, PGC-1 , and p-AMPK, inhibited IAV induced activation of MAPKs and NF-{kappa}B, and alleviated inflammatory response. The pharmacological antagonists of SIRT1 and PGC-1 , as well as siRNA, significantly counteracted the effects of Genipin on IAV replication and inflammation. In summary, we found that Genipin and its derivatives could significantly inhibit IAV replication and inflammation, possibly by activating the AMPK-SIRT1-PGC-1 signaling pathway and altering metabolic reprogramming.

pharmacology and toxicology↗

bioRxiv2024

Strawberry COP9 signalosome FvCSN5 regulates plant development and fruit ripening by facilitating polyamine oxidase FvPAO5 degradation to control polyamine and H2O2 homeostasis

Polyamines (PAs), mainly including putrescine, spermidine, and spermine, are essential for plant growth and development. However, the post-translational regulation of PA metabolism remains unknown. Here, we report the COP9 signalosome subunit 5A (FvCSN5A)-mediated degradation of the PA oxidase FvPAO5, which catalyzes the conversion of spermidine/spermine to produce H2O2. FvCSN5A is localized in the cytoplasm and nucleus, ubiquitously expressed in strawberry plants, and rapidly increases during fruit ripening. FvCSN5A RNA interference (RNAi) transgenic strawberries exhibit pleiotropic effects on plant development, fertility, and fruit ripening by regulating PA and H2O2 homeostasis, similar to FvPAO5 overexpression transgenic lines. FvCSN5A interacts with FvPAO5 in vitro and in vivo. The ubiquitination and degradation of FvPAO5 are impaired in FvCSN5A RNAi lines. Additionally, FvCSN5A interacts with cullin 1 (FvCUL1), a core component of the E3 ubiquitin-protein ligase complex. Transient genetic analysis in cultivated strawberry fruits showed that inhibiting FaPAO5 expression could partially rescue the ripening phenotype of FaCSN5A RNAi fruits. Collectively, the CSN5A-CUL1-PAO5 signaling pathway responsible for PA and H2O2 homeostasis is crucial to strawberry vegetative and reproductive growth and, final to fruit ripening. Our findings may open a promising avenue for improving crop yield and quality by manipulating the CSN5-PAO5 pair.

plant biology↗

bioRxiv2024

Charge distribution and helical content tune the binding of septins amphipathic helix domain to lipid membranes

Septins are a class of cytoskeletal proteins that preferentially bind to domains of micron-scale curvature on the cell membrane. Studies have shown that amphipathic helix (AH) domains in septin oligomers are essential for septin curvature sensing. Yet, the underlying mechanochemical interactions that modulate this curvature sensing remain ambiguous. Here we use all-atom molecular dynamics alongside a metadynamics enhanced sampling approach to bridge the gap between time and length scales required to optimize and validate experimental design of amphipathic helices. Simulations revealed that the local charge on the termini of an 18-amino-acid AH peptide impacts its helical content and positioning within lipid membranes. These computational observations are confirmed with experiments measuring the binding of synthetic AH constructs with variable helical content and charged termini to lipid vesicles. Taken together, these results identify the helical content of amphipathic helices as a regulator of septin binding affinity to lipid membranes. Additionally, we examined an extended AH sequence including 8 amino acids upstream and downstream of the minimal 18-amino-acid-long AH domain to more closely mimic the native protein in simulations and experiments. Simulations and experiments show that the extended peptide sequence adopts a strong alpha-helical conformation when free in solution, giving rise to a higher affinity to lipid membranes than that of the shorter AH sequence. Together, these results provide insight into how the native septin proteins interact with membranes, and establish general design principles that can guide the interaction of future synthetic materials with lipid membranes in a programmable manner. STATEMENT OF SIGNIFICANCEUnderstanding how cells sense and react to their shape is necessary for numerous biological processes. Here we explore the interactions between amphipathic helices, a curvature sensing protein motif, and lipid membranes. Using molecular dynamics simulations, enhanced simulation sampling techniques, and experiments, we find that increasing the helical content of the amphipathic helix or adding charged capping sequences yields higher membrane binding affinity. Understanding these parameters for membrane-binding could enable us to interface and regulate native protein functions, as well as guide the design of synthetic curvature-sensing materials that can interact with and deform lipid membranes.

biophysics↗

bioRxiv2024

Cnidaria XIAP activates caspase-mediated cell death

In vertebrate, X-linked inhibitor of apoptosis (XIAP) is a potent inhibitor of apoptosis. XIAP inhibits apoptosis by interacting with proapoptotic caspases via the baculovirus IAP repeat (BIR) domains and mediating caspase ubiquitination via the really interesting new gene (RING) domain and ubiquitin-associated (UBA) domain. In invertebrate, mostly arthropods, XIAP is also known as an apoptosis inhibitor. To date, no study on basal metazoan XIAP has been documented. In the present work, we examined the biological activity of XIAP from jellyfish Aurelia coerulea (AcXIAP) and other non-bilaterians. AcXIAP possesses three BIRs and one RING domain but lacks the UBA domain. AcXIAP augmented the apoptosis-inducing activity of all of the four A. coerulea caspases, of both the initiator and the effector clades, identified in this study. AcXIAP activated caspase via one of the BIRs, which bound and stabilized the caspase, and the RING domain, which mediated ubiquitination on the p20 subunit of the caspase in a lysine-independent manner. Similar caspase-activating properties were also observed in the XIAP of hydra, coral, and sponge. In hydra, XIAP knockdown markedly decreased cell death induced by an apoptosis inducer. Together these results revealed the unconventional function and working mechanism of XIAP in Cnidaria, and shed new light into the functional and structural evolution of XIAP.

cell biology↗

bioRxiv2024

Omicron-specific ultra-potent SARS-CoV-2 neutralizing antibodies targeting the N1/N2 loop of Spike N-terminal domain

A multitude of functional mutations continue to emerge on the N-terminal domain (NTD) of the spike protein in SARS-CoV-2 Omicron subvariants. Understanding the immunogenicity of Omicron NTD and the properties of antibodies elicited by it is crucial for comprehending the impact of NTD mutations on viral fitness and guiding vaccine design. In this study, we find that most of NTD-targeting antibodies isolated from individuals with BA.5/BF.7 breakthrough infection (BTI) are ancestral (wildtype or WT)-reactive and non-neutralizing. Surprisingly, we identified five ultra-potent neutralizing antibodies (NAbs) that can only bind to Omicron but not WT NTD. Structural analysis revealed that they bind to a unique epitope on the N1/N2 loop of NTD and interact with the receptor-binding domain (RBD) via the light chain. These Omicron-specific NAbs achieve neutralization through ACE2 competition and blockage of ACE2-mediated S1 shedding. However, BA.2.86 and BA.2.87.1, which carry insertions or deletions on the N1/N2 loop, can evade these antibodies. Together, we provided a detailed map of the NTD-targeting antibody repertoire in the post-Omicron era, demonstrating their vulnerability to NTD mutations enabled by its evolutionary flexibility, despite their potent neutralization. These results highlighted the importance of considering the immunogenicity of NTD in vaccine design. Author SummaryCOVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to be a major global public health concern four years after its emergence. The N-terminal domain (NTD) is a critical component of the spike glycoprotein, which is pivotal for SARS-CoV-2 cellular entry and serves as a primary target for antibody therapeutics and vaccine development. Characterizing the properties of antibodies elicited by NTD of Omicron sublineages is crucial for understanding viral evolution and guiding vaccine design. Here, we show that Omicron infection after vaccination induces majorly non-neutralizing NTD antibodies. Still, we identified a class of ultra-potent neutralizing antibodies (NAbs) which specifically bind to the NTD of Omicron sublineages. These NAbs neutralize the virus by competing with ACE2 and blocking ACE2-mediated S1 shedding. Structural analyses reveal that these antibodies target a unique epitope on the N1/N2 loop of NTD, and intriguingly interact with the receptor-binding domain (RBD) of spike glycoprotein. This class of NAbs with the special binding pattern, are escaped by BA.2.86 and BA.2.87.1 sublineages, shedding light on the role of recently emerged mutations in the N1/N2 loop of NTD. Our findings provide fresh insights into the immunogenicity of Omicron NTD, highlighting its capacity for antibody evasion due to its evolutionary flexibility. This underscores the importance of carefully considering the NTD component in vaccine design.

immunology↗

bioRxiv2024

Diffusion Basis Spectrum Imaging of White Matter in Schizophrenia and Bipolar Disorder

BackgroundMultiple studies point to the role of neuroinflammation in the pathophysiology of schizophrenia (SCZ), however, there have been few in vivo tools for imaging brain inflammation. Diffusion basis spectrum imaging (DBSI) is an advanced diffusion-based MRI method developed to quantitatively assess microstructural alternations relating to neuroinflammation, axonal fiber, and other white matter (WM) pathologies. MethodsWe acquired one-hour-long high-directional diffusion MRI data from young control (CON, n =27), schizophrenia (SCZ, n =21), and bipolar disorder (BPD, n =21) participants aged 18-30. We applied Tract-based Spatial Statistics (TBSS) to allow whole-brain WM analyses and compare DBSI-derived isotropic and anisotropic diffusion measures between groups. Clinical relationships of DBSI metrics with clinical symptoms were assessed across SCZ and control participants. ResultsIn SCZ participants, we found a generalized increase in DBSI-derived cellularity (a putative marker of neuroinflammation), a decrease in restricted fiber fraction (a putative marker of apparent axonal density), and an increase in extra-axonal water (a putative marker of vasogenic edema) across several WM tracts. There were only minimal WM abnormalities noted in BPD, mainly in regions of the corpus callosum (increase in DTI-derived RD and extra-axonal water). DBSI metrics showed significant partial correlations with psychosis and mood symptoms across groups. ConclusionOur findings suggest that SCZ involves generalized white matter neuroinflammation, decreased fiber density, and demyelination, which is not seen in bipolar disorder. Larger studies are needed to identify medication-related effects. DBSI metrics could help identify high-risk groups requiring early interventions to prevent the onset of psychosis and improve outcomes.

neuroscience↗

bioRxiv2024

A chromosome-level genome assembly of Dracaena cambodiana and comparative genomics analysis highlights the distinct biological features of two resource species of dragon's blood

This study reports a chromosome-level genome for Dracaena cambodiana, one of two typical dracaena species in China. This work will help to deepen the understanding of the dracaena species and the conservation and development of plant resources. The final assembly consisted of 54 scaffolds, spanning 1.08 Gb, with a scaffold N50 size of 52.29 Mb, encoded 36860 predicted protein-coding genes. A total of 1,064,810,157 bp of genome sequences were located on 20 chromosomes (2n = 40), accounting for 98.46%. We investigate the possible mechanisms of the longevity of dracaena, the longest-lived plant in the world, which involve DNA repair and post-translational modification. We also performed comparative genomic analysis of the previously assembled genome of Dracaena cochinchinesis with this genome, and found that the two involved interaction of plant-pathogen interaction and ubiquitin mediated proteolysis, which may reveal why Dracaena has environmental adaptability and longevity characteristics.

genomics↗

bioRxiv2024

Physical constraints and biological regulations underlie universal osmoresponses

Microorganisms constantly transition between environments with dramatically different external osmolarities. However, theories of microbial osmoresponse integrating physical constraints and biological regulations are lacking. Here, we propose such a theory, utilizing the separation of timescales for passive responses and active regulations. We demonstrate that regulations of osmolyte production and cell-wall synthesis assist cells in coping with intracellular crowding effects and adapting to a broad range of external osmolarity. Furthermore, we predict a threshold value above which cells cannot grow, ubiquitous across bacteria and yeast. Intriguingly, the theory predicts a dramatic speedup of cell growth after an abrupt decrease in external osmolarity due to cell-wall synthesis regulation. Our theory rationalizes the unusually fast growth observed in fission yeast after an oscillatory osmotic perturbation, and the predicted growth rate peaks match quantitatively with experimental measurements. Our study reveals the physical basis of osmoresponse, yielding farreaching implications for microbial physiology.

biophysics↗

bioRxiv2024

Unsilenced inhibitory cortical ensemble gates remote memory retrieval

Acquired information can be consolidated to remote memory for storage but persists in a dormant state until its retrieval. However, it remains unknown how dormant memory is reactivated. Using a combination of simultaneous two-photon calcium imaging and holographic optogenetics in the anterior cingulate cortex (ACC) in vivo, we discover a subset of GABAergic neurons that are specifically associated with dormant memory retrieval. These interneurons display persistent activity and inter-neuronal synchronization at the remote memory stage. In the absence of natural contextual cues, directly activating these interneurons reliably recalls cortical ensembles relevant to remote memory retrieval with context specificity. Conversely, targeted volumetric inactivation of these interneurons suppresses context-induced memory retrieval. Our results reveal an unexpected role of unsilenced inhibitory cortical ensembles in causally gating the retrievability of dormant remote memory.

neuroscience↗

bioRxiv2024

Phospholipase Cgamma regulates lacrimal gland branching by competing with PI3K in phosphoinositide metabolism

Although the regulation of branching morphogenesis by spatially distributed cues is well established, the role of intracellular signaling in determining the branching pattern remains poorly understood. In this study, we investigated the regulation and function of phospholipase C gamma (PLC{gamma}) in Fibroblast Growth Factor (FGF) signaling in lacrimal gland development. We showed that deletion of PLC{gamma}1 in the lacrimal gland epithelium leads to ectopic branching and acinar hyperplasia, which was phenocopied by either mutating the PLC{gamma}1 binding site on Fgfr2 or disabling any of its SH2 domains. PLC{gamma}1 inactivation did not change the level of Fgfr2 or affect MAPK signaling, but instead led to sustained AKT phosphorylation due to increased PIP3 production. Consistent with this, PLC{gamma}1 mutant phenotype can be reproduced by elevation of PI3K signaling in Pten knockout and attenuated by blocking AKT signaling. This study demonstrated that PLC{gamma} modulates PI3K signaling by shifting phosphoinositide metabolism, revealing an important role of signaling dynamics in conjunction with spatial cues in shaping branching morphogenesis.

developmental biology↗

bioRxiv2024

Crk mediates Csk-Hippo signaling independently of Yap tyrosine phosphorylation to induce cell extrusion

Src family kinases (SFKs), including Src, Fyn and Yes, play important roles in development and cancer. Despite being first discovered as the Yes-associated protein, the regulation of Yap by SFKs remains poorly understood. Here, through single-cell analysis and genetic lineage tracing, we show that the pan-epithelial ablation of C-terminal Src kinase (Csk) in the lacrimal gland unleashes broad Src signaling but specifically causes extrusion and apoptosis of acinar progenitors at a time when they are shielded by myoepithelial cells from the basement membrane. Csk mutants can be phenocopied by constitutively active Yap and rescued by deleting Yap or Taz, indicating a significant functional overlap between Src and Yap signaling. Although Src-induced tyrosine phosphorylation has long been believed to regulate Yap activity, we find that mutating these tyrosine residues in both Yap and Taz fails to perturb mouse development or alleviate the Csk lacrimal gland phenotype. In contrast, Yap loses Hippo signaling-dependent serine phosphorylation and translocates into the nucleus in Csk mutants. Further chemical genetics studies demonstrate that acute inhibition of Csk enhances Crk/CrkL phosphorylation and Rac1 activity, whereas removing Crk/CrkL or Rac1/Rap1 ameliorates the Csk mutant phenotype. These results show that Src controls Hippo-Yap signaling through the Crk/CrkL-Rac/Rap axis to promote cell extrusion.

developmental biology↗