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Chen, X.

Publications and source records attributed to Chen, X..

At least 181 records · Page 10Linked to original sources

Towards building a World Model to simulate perturbation-induced cellular dynamics by AlphaCell

Predicting cellular responses to perturbations is crucial for therapeutic discovery, yet experimental screening is severely constrained by the combinatorial vastness of biological space. While computational simulations offer a scalable alternative, current models are limited by the incomplete latent representation----mainly relying on highly variable genes in feature representation; the poor genome-wide reconstruction fidelity; and the ungeneralizable dynamic laws across diverse contexts. Consequently, they fail to mechanistically transfer learned dynamics to unseen cellular contexts. To address these systemic flaws, we introduce AlphaCell, a generative Virtual Cell World Model that unifies genome-wise representation with continuous state transition modeling. AlphaCell achieves three synergistic innovations: (1) Latent Manifold Rectification, processing the full protein-coding transcriptome to construct a differentiable Virtual Cell Space, effectively filtering noise while preserving intrinsic cellular topology; (2) Biological Reality Reconstruction, utilizing a massive, knowledge-rich decoder to translate abstract latent states back into high-fidelity, genome-wide expression profiles; and (3) Universal State Transition, applying Optimal Transport Conditional Flow Matching to model perturbations as continuous, deterministic vector fields. By abstracting perturbation mechanisms into generalized dynamic laws, AlphaCell makes robust prediction of perturbation responses in a compositional generalization scenario and enables zero-shot prediction of cellular dynamics in entirely unseen cellular contexts, providing a foundational engine for cellular-context-generalizable perturbation prediction and perturbation-induced cellular dynamics simulation.

bioinformatics↗

Single-Nucleus Transcriptomics Reveals Cell Type-Specific Remodeling and Epilepsy-Associated Microglia

Mesial temporal lobe epilepsy (TLE) is the most common form of acquired epilepsy involving the hippocampus and is a frequent sequelae of head trauma. TLE is associated with refractory seizures and significant cognitive deficits. Yet, the gene expression patterns and cell types driving epileptogenesis and the associated cognitive deficits are poorly understood. To address this, we performed single nucleus RNA sequencing on hippocampal tissue from mice at 3 and 6 weeks following pilocarpine-induced status epilepticus, a robust model of TLE. At these early timepoints, epilepsy samples showed reductions in specific Cck and Lamp5-Lhx6 interneuron subclusters, alongside increases in Cajal-Retzius cells, dentate granule (DG) cell precursors, and a mature DG cell subcluster. Among glia, an astrocyte subcluster and a markedly expanded microglia sublcuster were increased. We term this microglia population epilepsy-associated microglia (EAM). The transcriptomic profile of EAM partially overlaps with microglia described in models of Alzheimers disease and traumatic brain injury, with enrichment of genes including Myo1e and Igf1. EAM display amoeboid morphology, can be found in dense clumps around pyramidal and granule cell body layers, and exhibit enlarged vesicles and mitochondria on electron microscopy. Cell-cell interaction analysis predict that DG cells are the main interaction partners of EAM. This dataset recapitulates known cellular alterations in TLE while defining their underlying transcriptomic programs, enabling mechanistic dissection of the key processes driving epileptogenesis.

neuroscience↗

Presymptomatic plant disease detection with PSNet: A low-cost hyperspectral imaging and RGB fusion framework.

Plant pathogens cause yield losses worldwide, threatening food security and livelihoods. Because early infection is difficult to diagnose, management often relies on prophylactic pesticide use, increasing costs and environmental impact. Here we present PSNet, a multimodal framework that fuses hyperspectral imaging with RGB information for presymptomatic plant disease detection, together with a low-cost hyperspectral camera incorporating a 3D-printed housing, costing under {pound}500. We validate PSNet using Arabidopsis thaliana infected with the oomycete Albugo candida. Imaging at 2 and 4 days post inoculation, prior to visible symptoms, revealed spectral signatures that distinguished infected from healthy plants, while imaging at 6 days post inoculation captured the transition toward early symptom emergence. Discriminative spectral regions overlapped wavelengths associated with plant responses to biotic stress, supporting the biological plausibility of these signatures. Performance was evaluated using strict plant-level partitioning, ensuring samples from the same plant were confined to a single split. On a four-class task (healthy, 2 dpi, 4 dpi, 6 dpi), PSNet achieved 90.00% accuracy and 97.50% accuracy for binary classification. Together, these results demonstrate that presymptomatic detection is feasible under controlled conditions using low-cost hardware and multimodal learning, underscoring the potential of scalable multimodal systems for early disease monitoring.

plant biology↗

Exploration of the screening and regulatory mechanisms of biomarkers related to ac4C modification in laryngeal squamous cell carcinoma patients based on single-cell analysis and machine learning

BackgroundN4-acetylcytidine (ac4C) modification plays a critical role in cancer development. Exploring ac4C modification in laryngeal squamous cell carcinoma (LSCC) may help elucidate its pathogenesis. MethodsLSCC-related datasets were obtained from GEO. After preprocessing and annotating single-cell data, malignant cells were identified by CNV scoring and further divided into subpopulations. Malignant epithelial cells (MECs) were identified and subclustered based on ac4C-related gene activity. Prognostic genes were screened using Cox regression and machine-learning approaches, followed by validation in clinical samples using qPCR. The biological and immunological relevance of these genes was further explored through immune infiltration, immunotherapy response, and mutation analyses. ResultsThe 14,465 identified MECs were classified into five subgroups (MEC1-5), among which MEC3 showed the strongest association with the ac4C gene set. Machine-learning analysis of MEC3-derived genes yielded seven prognostic markers, including BARX1, FHL2, NXPH4, PKMYT1, TNFAIP8L1, CRLF1, and CENPP. qPCR confirmed their differential expression between tumor and adjacent normal tissues. These genes were significantly associated with alterations in the tumor immune microenvironment, with high-risk patients showing increased immune infiltration and immune activity. ConclusionSeven ac4C-related prognostic genes were identified that may contribute to LSCC progression by modulating the tumor immune microenvironment, providing potential therapeutic insights.

developmental biology↗

Therapeutic targeting inflammation linking periodontitis and atherosclerotic comorbidities using cell-free DNA-capturing nanomaterials

Periodontitis-associated systemic inflammation makes it a great challenge to explore therapeutic options applicable to periodontitis and atherosclerotic comorbidities. Here, we identify the crucial role of cell-free DNA (cfDNA) that underlies these comorbidities. Hypothesizing cfDNA as a therapeutic target, we engineer polyamidoamine dendrimer-functionalized nanomaterials to modulate such local-systemic inflammatory crosstalk. Periodontium-originated DNA can be systemically captured by cationic nanomaterials, and capturing cfDNA, whether locally or systemically, alleviates both periodontitis and atherosclerosis prior to severe atherosclerotic development in vivo. The transcriptomic and single-cell RNA sequencing analyses together reveal that cfDNA-capturing nanomaterials regulate inflammatory foam cell transformation in macrophages by modulating the expression of lipid-related foamy markers Spp1 and Fabp4. This study provides a proof of concept for cfDNA-driven periodontitis-atherosclerosis crosstalk, and offers a cfDNA-capturing nanoplatform for therapeutic intervention targeting periodontitis and atherosclerotic comorbidities in a holistic fashion.

immunology↗

Cell-type specific impact of opioid use disorder and HIV on the human forebrain and cerebellum

Opioid use disorder (OUD), which frequently co-occurs with HIV infection, causes long-term neurological disease, yet the epigenetic and transcriptomic effects of OUD and HIV on specific cell types and regions of the brain are poorly understood. To assess the cell-type specific impacts of OUD and HIV across the human brain, we measured single cell transcriptomes and epigenomes of 580,353 cells in the prefrontal cortex, amygdala and cerebellum of 44 donors. We cataloged over 750k candidate cis-regulatory elements (cCREs) and identified gene regulatory networks (GRNs) of transcription factor activity across 35 neuronal and non-neuronal cell types. We identified specific neuronal and glial populations whose cCREs were significantly enriched for genetic risk of addiction-related traits. In OUD donors, we found evidence for reduced metabolic function in neurons in the PFC and cerebellum as well as increased gene expression related to voltage-gated calcium channel activity in the cerebellum. Using a cerebellar organoid model, fentanyl treatment reduced metabolic activity while increasing neuronal activity. Across brain regions, HIV activated immune-related pathways in glial populations, while comorbid OUD and HIV exacerbated metabolic changes in cortical glial cells. Cerebellum-specific Bergmann glia, in addition to forebrain microglia and astrocytes, showed expansion of reactive state identity in HIV. These results highlight shared and specific changes to immune, synaptic, and metabolic processes in OUD and HIV across brain regions and reveal that cerebellar cell types are distinctly affected by opioid abuse.

genomics↗

Minimal biophysical rules are sufficient for the emergence of computational intelligence at the neuronal scale

How intelligence emerges from the brains complex microscopic physical system is a central question for neuroscience and artificial intelligence. Constrained by the genomic bottleneck that precludes synapse-by-synapse specification, we propose and validate a microscopic structure-function concise-constraint sufficiency hypothesis. We develop the Neuro-Informed Generative Connectome (NIGC) framework, and show that connectomes generated under a concise set of biophysical constraints (geometric embedding, node propensity modulation, a global energy budget and maximum-entropy selection) closely match the structural statistics of a measured mouse V1 microcircuit (similarities, 0.997). In parallel, using the generated connectome as the fixed reservoir of an echo state network (ESN), training only a linear readout achieves 90% accuracy on an auditory multi-classification task. Moreover, multidimensional biologically consistent functional phenotypes, such as hierarchical transmission delays and low-dimensional spatiotemporal trajectories, are obtained without fitting functional matrices or time courses. Further, by combining single-constraint ablations, pathological perturbations and cross-modal validation, we clarify how specific structural constraints map onto functional consequences. Together, these results delineate sufficient conditions for computational intelligence emergence at the microscopic scale, and provide an auditable benchmark for first-principles understanding of brain construction.

neuroscience↗

Targeting phosphodiesterase 10A disrupts MAPK signaling pathways in the tumor microenvironment to unleash antitumor immunity

Phosphodiesterase 10A (PDE10A), a cyclic nucleotide-degrading enzyme, is overexpressed in various human cancers. While PDE10A inhibition using small-molecule inhibitors or gene silencing suppresses tumor growth in xenograft models, its precise mechanism of action and immunological impact remain unclear. Here, we report that ADT-030, a novel PDE10A inhibitor, exhibits potent cytotoxicity against a broad range of murine tumor cell lines. ADT-030 is orally bioavailable and effectively suppresses tumor growth across multiple syngeneic mouse models. Notably, its efficacy is diminished in immunodeficient mice or upon CD8+ T cell depletion, highlighting a critical dependence on host immunity. The immunostimulatory properties of ADT-030 are further supported by its ability to induce immunogenic tumor cell death and promote dendritic cell (DC) maturation, its reliance on Batf3-expressing DCs to elicit antitumor CD8+ T cell response, and its synergy with anti-PD-1 therapy. Comprehensive immune profiling in the 4T1 breast cancer model, both in orthotopic and metastatic settings, revealed that ADT-030 selectively reduces myeloid-derived suppressor cells (MDSCs) while normalizing the immune landscape within the tumor. Mechanistically, ADT-030 disrupts multiple components of the mitogen-activated protein kinase (MAPK) signaling network in both tumor cells and MDSCs, leading to induction of apoptosis in these populations. These findings highlight the multi-faceted impact of PDE10A inhibition as a therapeutic strategy that not only disrupts tumor-intrinsic oncogenic signaling to inhibit tumor progression but also reshapes the tumor immune microenvironment to unleash antitumor immunity.

immunology↗

The structure and catalytic mechanism of new cellular and viral HDV ribozymes

We have determined the molecular structure and investigated the catalytic mechanism of two new ribozymes of the Hepatitis delta virus family, found in the nematode Caenorhabditis briggsae and virus Ackermannviridae. Crystal structures of both conform to the double-pseudoknot architecture adopted by the viral HDV ribozyme. The C. briggsae ribozyme has been determined both pre- and post-cleavage. In the former both nucleotides flanking the scissile phosphate are observed, along with a metal ion, and cytosine 75 N3 bound to the O5 leaving group. The pH dependence of cleavage rate reveals a pKa of 6.6 and together with the inactivity of a C75U mutant provides evidence for its role as general acid. In contrast to other nucleolytic ribozymes that use catalytic metal ions, reaction rate does not depend on the pKa of the divalent metal ion. Limited adjustment of structure of the active center is consistent with direct bonding of the metal ion to the O2 and non-bridging O, suggesting that the ion acts as a Lewis acid to activate nucleophilic attack. This mechanism appears to be general for the HDV ribozyme class, and distinguishes it from the majority of nucleolytic ribozymes that use general base catalysis.

biochemistry↗

Voltage-gated calcium channel activity of gonadotropin-releasing hormone (GnRH) neurons is altered by age and by prenatal androgen exposure in female mice

Polycystic ovary syndrome (PCOS), a common cause of infertility, is marked by persistently high luteinizing hormone (LH)-pulse frequency, presumably driven by high-frequency GnRH pulses. Prenatally androgenized (PNA) mice mimic neuroendocrine PCOS symptoms including high LH-pulse frequency. GnRH neurons from adult PNA mice have a higher firing rate than those from vehicle (VEH) mice; this is reversed in prepubertal mice despite more excitatory inputs at both ages. We hypothesized voltage-gated Ca2+ currents (ICa) help set intrinsic excitability of GnRH neurons and are altered by development and/or PNA treatment. Whole-cell patch-clamp recordings were used to measure GnRH neuron ICa in 3wk-old and adult VEH and PNA mice. PNA treatment increased ICa density and depolarized the ICa-half inactivation potential at both ages. In VEH but not PNA mice, the Ca2+-half activation potential was depolarized in adults versus 3wks. Age decreased the inactivation rate of a fast ICa regardless of PNA treatment. GnRH neuron firing rate during current injections was higher at 3wks than in adulthood in VEH mice only. Blocking small-conductance Ca{superscript 2}-activated K current with apamin increased GnRH neuron firing rate except in adult PNA mice. Apamin changed the post-spike-train membrane response from hyperpolarization to depolarization; during development, this net effect of apamin became smaller in PNA mice. In summary, while GnRH neurons from PNA mice have increased ICa, they lack some developmental changes in ICa kinetics and intrinsic excitability observed in VEH mice. Ca{superscript 2}-activated K currents are less prominent in GnRH neurons from adult PNA mice, perhaps contributing to increased spontaneous firing. Significance statementHyperactivation of GnRH neurons, which control reproductive endocrine function, can lead to increased LH-pulse frequency and is a hallmark of hyperandrogenemia polycystic ovary syndrome (PCOS). We used a mouse model of prenatal androgenization (PNA) that recapitulates the neuroendocrine aspects of PCOS to test the role of calcium currents (ICa) in the PNA phenotype and the typical pubertal process. PNA treatment increased ICa in GnRH neurons both before and after puberty. Calcium plays a crucial role in neurosecretion thus this may enhance GnRH release. Another role of calcium is activation of calcium-sensitive potassium currents, which tend to decrease action potential firing rate. Despite increased ICa, calcium-activated potassium currents are less effective in adult PNA mice, perhaps contributing to GnRH neuron hyperactivation.

neuroscience↗

Explaining the unexplained admixture mapping signals via rare variants: the HCHS/SOL

In admixed populations, formed by a mixing of two or more previously isolated populations, genomic segments can be traced to their ancestral populations ("ancestries"). Admixture mapping (AM) associates local ancestry with outcomes in admixed populations, detecting signals when causal variants differ in frequency or effect across ancestral populations. Prior work showed that adjusting for nearby GWAS-identified common variants does not fully explain some AM signals. Here, we assessed two approaches to explain the previously unexplained AM signal: (1) including sets of rare variants; (2) increasing the genomic region considered when searching for common variants. We studied these hypotheses comprehensively using a whole-genome sequencing dataset coupled with metabolomics from the Hispanic Community Health Study/Study of Latinos. We detected multiple sets of rare variants with replicated association with metabolite levels. Yet these rare variants appear to explain only a small fraction of the AM signal, while inclusion of common variants from a larger genomic region appears to explain the majority of the AM signals.

genetics↗

Memory T cell rapid recall is driven by memory-specific AP-1 recruitment determined by epigenome and co-factor interactions

CD4 T cell memory is essential for long-lasting protective immunity to repeat infections. Unlike naive T cells, memory cells possess rapid recall ability to quickly produce effector molecules in response to antigen re-exposure. This ability was shown to be associated with epigenetic gene poising. Here, we examine how the activation-inducible transcription factors, AP{square}1 and NF{square}{kappa}B, regulate rapid recall gene expression. We found that AP-1 is required for their induction and that the enhanced induction of rapid recall genes in memory cells is associated with memory-specific binding of AP{square}1. Memory-specific AP{square}1 binding, in turn, is enabled by enhanced chromatin accessibility and reduced DNA methylation at regulatory elements. As the AP-1 DNA-binding motif itself does not contain methylatable CpGs, methylation likely affects the binding of AP-1 co-factors, such as ETS proteins, or accessibility of the region in general. Finally, both common and memory-specific AP{square}1/NF{square}{kappa}B binding sites show strong overlap with autoimmune and inflammatory disease risk variants, highlighting the clinical relevance of memory T cell epigenetic regulation.

immunology↗

SMARCAL1 is a candidate therapeutic target for ALT-positive tumors

A significant subset of tumors, including over 50% of osteosarcomas--an aggressive bone malignancy affecting children, adolescents, and young adults--relies on alternative lengthening of telomeres (ALT), a telomerase-independent, DNA repair-based mechanism for telomere elongation. The overall 5-year survival rate for osteosarcoma patients is [~]65%, underlying the need to develop novel targeted therapies. Through the Cancer Dependency Map, we identify SMARCAL1, a DNA translocase previously shown to remodel stalled replication forks, as a top selective dependency factor in telomerase-negative tumors. Using a panel of ALT-positive and ALT-negative cancer cell lines, as well as osteosarcoma patient-derived xenograft cells, we confirm that ALT-positive cells are uniquely sensitive to the loss of SMARCAL1, whose depletion exacerbates ALT-dependent phenotypes and telomeric DNA damage. Notably, we demonstrate that suppressing ALT abrogates their dependency on SMARCAL1. Mechanistically, we show that SMARCAL1 loss leads to telomeric ssDNA accumulation in ALT-positive cells, dependent in part on DNA repriming mediated by the DNA primase/polymerase PRIMPOL. Moreover, SMARCAL1s ssDNA annealing activity counteracts DNA unwinding by the BLM helicase, limiting telomeric ssDNA accumulation and DNA damage in ALT-positive cells. Importantly, SMARCAL1 depletion induces senescence in ALT-positive cancer cells, rendering them susceptible to treatment with senolytic agents. Together, these findings establish SMARCAL1 as a key regulator of ALT metabolism and highlight SMARCAL1 as a promising therapeutic target for ALT-positive tumors.

cancer biology↗

ADT-030, a novel PDE10 inhibitor, demonstrates potent antitumor activity in pancreatic ductal adenocarcinoma

Phosphodiesterase 10 (PDE10) has been noted to be highly expressed in multiple types of cancer and is crucial for the growth and maintenance of cancer cells found in colon, lung, and ovarian cancers. Here, we studied a novel orally bioavailable PDE10 inhibitor, ADT-030, and found that it potently inhibits the proliferation and clonogenicity of KRAS-mutant pancreatic ductal adenocarcinoma (PDAC) cells at levels that block recombinant PDE10. ADT-030 also inhibited PDAC cell motility and triggered G2/M cell cycle halt and programmed cell death. These impacts were facilitated by raised cAMP/cGMP levels, activation of PKA/PKG, reduced {beta}-catenin and RAS signaling. Notably, ADT-030 diminished the proliferation of PDAC cells with KRASG12D and KRASG12C mutations that were resistant to both allele-specific and pan-RAS inhibitors. When administered orally, ADT-030 markedly decreased tumor growth, lowered the metastasis to the lungs and liver, and enhanced survival rates without causing systemic toxicity in both syngeneic and patient-derived xenograft (PDX) models of PDAC. ADT-030 also increased chemotherapy response in orthotopic PDAC models. Immune phenotyping and single-cell RNA sequencing revealed remodeling of the tumor microenvironment by ADT-030 with a more favorable anti-tumor immune profile. The findings suggest that ADT-030 holds promise as a potential drug development candidate for treating KRAS-mutant PDAC by simultaneously targeting key oncogenic signaling pathways, resulting in tumor-intrinsic and immunomodulatory effects.

cancer biology↗

Coexistent PTEN and PIK3CA alterations hyperactivate mTORC1 signaling in endometrial cancers and cause their selective sensitivity to mTORC1 inhibition

In approximately half of endometrial carcinoma (EC), PTEN loss-of-function and activating PI3K mutants coexist. Unlike cells with either single mutation, PTEN/PIK3CA coexistent alterations result in elevated membrane phosphatidylinositol (3,4,5)-trisphosphate (PIP3) levels and mTORC1 hyperactivation, rendering PI3K or AKT inhibition ineffective in blocking mTORC1 activity and tumor growth. The bi-steric mTORC1 kinase inhibitor, RMC-6272, suppresses mTORC1 activity and cell growth by reducing protein translation and cell cycle progression. In vivo, RMC-6272, but not PI3K inhibitors, effectively suppressed mTORC1 and growth of EC PDXs with coexistent PTEN/PIK3CA lesions. These findings are consistent with a phase I trial of bi-steric mTORC1 inhibitor RMC-5552, showing anti-tumor activity in patients with EC. PDXs with KRAS co-mutations regrew after RMC-6272 treatment, which was prevented by the addition of the RAS(ON) multi-selective inhibitor RMC-7977. Overall, these data suggest that mTORC1 hyperactivation drives ECs with coexistent PTEN/PIK3CA mutations, explain the limited antitumor activity of PI3K and AKT inhibitors, and support clinical evaluation of mTORC1 inhibitors as potential therapy for EC. SignificanceWe have found the mechanistic consequences of PTEN/PIK3CA co-alterations in endometrial tumors and that these mutations result in a profound hyperactivation of mTORC1 signaling. Single mutant tumors are sensitive to PI3K inhibition but those with both mutations are insensitive to PI3K or AKT inhibition but are exquisitely dependent on mTORC1 kinase. This provides strong preclinical rationale for targeting mTORC1, alone or combined with RAS inhibition (in RAS co-mutant tumors), as an effective therapeutic strategy.

cancer biology↗

The genome of an aneuploid cultivar facilitates elucidating the genetic bases of trait polymorphisms in Phalaenopsis orchids

As an important ornamental crop, Phalaenopsis orchids exhibit extraordinary trait diversity with unclear genetic bases. Here, we present a haplotype-resolved, chromosome-level genome for an aneuploid cultivar Santiago. We reveal pervasive variation in the number and sequence among homoeologous genes. When serving as a reference, this genome facilitates the genetic understanding of trait variation in a hybrid population that is highly representative in trait polymorphisms. Specifically, nucleotide polymorphisms in a potential long-distance enhancer and the consequential expression variation of PsAGL6-2, presence/absence of PsMYB12 and b-type homoeologous gene of PsMYB2 determine lip morphology variation, presence/absence of venation-associated stripes and background pink color, respectively. Diverse functions of PsMYBx1 in repressing anthocyanin accumulation across different cultivars further enhances the color patterning diversity in Phalaenopsis. Our study provides a practical framework for using a highly heterogeneous, haplotype-resolved genome to decode phenotypic diversity and has the potential to promote marker-assisted breeding in Phalaenopsis.

genomics↗

MNS induces antiviral protection and suppresses inflammation

BackgroundIdentifying safe and broad-spectrum antiviral and anti-inflammatory agents remains an urgent need in infectious and inflammatory diseases. Here, we demonstrated that MNS (NSC170724), a small-molecule nitrovinyl benzodioxole, enhanced antiviral defense while limiting excessive inflammation. MethodsThe antiviral activity of MNS was evaluated in multiple cell lines and mouse infection models across DNA and RNA viruses. Virus-induced and LPS-induced inflammatory responses were assessed using RT-qPCR, ELISA and western blotting. Bulk RNA-seq and ATAC-seq were performed to define transcriptional and epigenetic mechanisms. ResultsMNS significantly suppressed viral infection in vitro and improved survival in four lethal viral infection models, accompanied by reduced viral loads and attenuated tissue injury. MNS also diminished virus-triggered and LPS-triggered inflammatory cytokine production in macrophages and multiple mouse organs, and protected mice from LPS-induced endotoxic lethality. Multi-omics profiling showed that MNS broadly repressed LPS-induced inflammatory transcriptional programs and reversed chromatin accessibility gains across promoters and transcription start sites. Joint analysis of RNA-seq and ATAC-seq data demonstrated consistent downregulation of pivotal inflammatory pathways, such as NF-{kappa}B, Toll-like receptor, and TNF signaling. ConclusionsWith potent activity against viral replication and inflammation in cellular and animal models, MNS emerges as a promising candidate for the treatment of viral infections and hyperinflammatory conditions.

systems biology↗

Nerve Injury-Induced Protein 2 Is Necessary for the Lysosome Membrane Integrity and Protects Cells from Ferroptosis

Nerve injury-induced protein 1 (NINJ1), a cell adhesion molecule, is oligomerized during lytic cell death and mediates plasma membrane rupture to release large intracellular molecules that propagate the inflammatory response. We and others previously showed that NINJ2, a close relative of NINJ1, does not promote plasma membrane rupture to spread inflammation. Here, we identify that NINJ2 is necessary for the lysosome membrane integrity to protect cells from ferroptosis. Specifically, we found that NINJ2 localizes to lysosomes and interacts with LAMP1, an anchor glycoprotein of the lysosome membranes and a sensor of stressed lysosomes. We also found that loss of NINJ2 exacerbates lysosomal membrane permeabilization (LMP), which allows for selective leakage of lysosomal contents, such as labile iron, into the cytosol. Accordingly, loss of NINJ2 elevates cellular labile iron accumulation and decreases expression of ferritins, the primary intracellular iron storage protein complexes. Mechanistically, we found that loss of NINJ2 promotes ferritin FTH degradation in lysosomes, which can be reversed by knockdown of LAMP1. Moreover, we found that loss of NINJ2 sensitizes cells to ferroptosis induced by RSL3 and Erastin, consistent with a recent study that loss of Ninj2 predisposes mice to chronic inflammation. Together, these findings uncover a previously unrecognized activity of NINJ2 from lysosome homeostasis to ferroptosis, which can be explored as a cancer therapeutic strategy especially considering that NINJ2 and ferritins are found to be overexpressed and positively associated with iron-addicted cancers.

cancer biology↗