Biology subjects

Lu, D.

Publications and source records attributed to Lu, D..

At least 73 records · Page 4Linked to original sources

bioRxiv2024

Microvilli regulate the release modes of alpha-tectorin to organize the domain-specific matrix architecture of the tectorial membrane.

The tectorial membrane (TM) is an apical extracellular matrix (ECM) in the cochlea essential for auditory transduction. The TM exhibits highly ordered domain-specific architecture. Alpha-tectorin/TECTA is a glycosylphosphatidylinositol (GPI)-anchored ECM protein essential for TM organization. Here, we identified that TECTA is released by distinct modes: proteolytic shedding by TMPRSS2 and GPI-anchor-dependent release from the microvillus tip. In the medial/limbal domain, proteolytically shed TECTA forms dense fibers. In the lateral/body domain produced by the supporting cells displaying dense microvilli, the proteolytic shedding restricts TECTA to the microvillus tip and compartmentalizes the collagen-binding site. The tip-localized TECTA, in turn, is released in a GPI-anchor-dependent manner to form collagen-crosslinking fibers, required for maintaining the spacing and parallel organization of collagen fibrils. Overall, we showed that distinct release modes of TECTA determine the domain-specific organization pattern, and the microvillus coordinates the release modes along its membrane to organize the higher-order ECM architecture. O_FIG O_LINKSMALLFIG WIDTH=146 HEIGHT=200 SRC="FIGDIR/small/574255v1_ufig1.gif" ALT="Figure 1"> View larger version (36K): org.highwire.dtl.DTLVardef@10479c6org.highwire.dtl.DTLVardef@d6cb33org.highwire.dtl.DTLVardef@1b6b4fdorg.highwire.dtl.DTLVardef@2477f4_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical AbstractC_FLOATNO C_FIG

developmental biology↗

bioRxiv2024

The Interpretable Multimodal Machine Learning (IMML) framework reveals pathological signatures of distal sensorimotor polyneuropathy

Distal sensorimotor polyneuropathy (DSPN) is a common neurological disorder in elderly adults and people with obesity, prediabetes and diabetes and is associated with high morbidity and premature mortality. DSPN is a multifactorial disease and not fully understood yet. Here, we developed the Interpretable Multimodal Machine Learning (IMML) framework for predicting DSPN prevalence and incidence based on sparse multimodal data. Exploiting IMMLs interpretability further empowered biomarker identification. We leveraged the population-based KORA F4/FF4 cohort including 1,091 participants and their deep multimodal characterisation, i.e. clinical data, genomics, methylomics, transcriptomics, proteomics, inflammatory proteins and metabolomics. Clinical data alone is sufficient to stratify individuals with and without DSPN (AUROC = 0.752), whilst predicting DSPN incidence 6.5{+/-}0.2 years later strongly benefits from clinical data complemented with two or more molecular modalities (improved {Delta}AUROC >0.1, achieved AUROC of 0.714). Important and interpretable features of incident DSPN prediction include up-regulation of proinflammatory cytokines, down-regulation of SUMOylation pathway and essential fatty acids, thus yielding novel insights in the disease pathophysiology. These may become biomarkers for incident DSPN, guide prevention strategies and serve as proof of concept for the utility of IMML in studying complex diseases.

bioinformatics↗

bioRxiv2023

General Anesthesia Activates a Central Anxiolytic Center in the BNST

Low doses of general anesthetics like ketamine and dexmedetomidine have anxiolytic properties independent of their sedative effects. How these different drugs exert these anxiolytic effects is not well understood. We discovered a population of GABAergic neurons in the oval division of the bed nucleus of the stria terminalis that is activated by multiple anesthetics and the anxiolytic drug diazepam (ovBNSTGA). A majority of ovBNSTGA neurons express neurotensin receptor 1 (Ntsr1) and innervate brain regions known to regulate anxiety and stress responses. Optogenetic activation ovBNSTGA or ovBNSTNtsr1 neurons significantly attenuated anxiety-like behaviors in both naive animals and mice with inflammatory pain, while inhibition of these cells increased anxiety. Notably, activation of these neurons decreased heart rate and increased heart rate variability, suggesting that they reduce anxiety through modulation of the autonomic nervous system. Our study identifies ovBNSTGA/ovBNSTNtsr1 neurons as one of the brains endogenous anxiolytic centers and a potential therapeutic target for treating anxiety-related disorders. HIGHLIGHTSO_LIGeneral anesthetics and anxiolytics activate a population of neurons in the ovBNST C_LIO_LIAnesthesia-activated ovBNST neurons bidirectionally modulate anxiety-like behavior C_LIO_LIMost anesthesia-activated ovBNST neurons express neurotensin receptor 1 C_LIO_LIovBNSTNtsr1 neuron activation shifts autonomic responses to an anxiolytic state C_LI

neuroscience↗

bioRxiv2023

Computational divergence analysis reveals the existence of regulatory degeneration and supports HDAC1 as a potential drug target for Alzheimer's disease

Epigenetic dysregulation has been widely reported in patients of Alzheimers disease (AD) and epigenetic drugs are gaining particular interest as a potential candidate therapy target. However, it is less clear how epigenetic dysregulation contributes to AD development. In this work, we performed regulatory divergence analysis using large-scale AD brain RNA-seq data and reported a widespread existence of regulatory degeneration among AD patients. It seems that transcription factor (TF)-mediated regulations get weakened or lost during AD development, resulting in disruption of normal neuronal function, especially including protein degradation, neuroinflammation, mitochondria and synaptic dysfunction. The regulatory degeneration burden (RDB) is well correlated with the detrimental clinical manifestations of AD patients. Studies of epigenetic marks, including histone modification, open chromatin accessibility and three TF binding sites supported the existence of regulatory degeneration. It suggested that epigenetic dysregulation contributed to regulatory degeneration, which also explained the consequence of epigenetic dysregulation. Among the epigenetic regulators, HDAC1 was proposed as a potential participator in such a process. Overall, our computational analysis suggested a novel causal mechanism of AD development and proposed HDAC1 as a drug target to treat AD.

systems biology↗

bioRxiv2023

A conserved ion channel function of STING mediates non-canonical autophagy and cell death

The cGAS/STING pathway triggers inflammation in response to diverse cellular stresses such as infection, cellular damage, senescence, normal aging, and age-related disease. Besides inflammation, STING also triggers non-canonical autophagy and cell death, the former of which requires the proton pump V-ATPase- mediated LC3 lipidation to single membrane STING vesicles. V-ATPase is known to sense organelle de- acidification in other contexts and recruits the ATG16L1 complex for direct conjugation of LC3/ATG8 to single membranes (CASM). However, it is unclear how STING activates V-ATPase for non-canonical autophagy. Here we report that upon STING activation, the transmembrane domain (TMD) of STING significantly reorganizes and forms an electron-sparse pore in the center. Cellular imaging and in vitro ion flux assays revealed that STING is critical for proton efflux and pH neutralization of Golgi-derived STING vesicles. A chemical ligand of STING, C53, which binds to and blocks the channel of STING strongly inhibited STING-mediated proton flux in vitro and vesicular de-acidification in cells. C53 also abolished STING-dependent LC3 lipidation and cell death. Thus, the ion channel function of STING activates non-canonical autophagy and cell death through vesicle de-acidification.

biochemistry↗

bioRxiv2023

Antagonism of kappa opioid receptors worsens the development of L-DOPA-induced dyskinesia in a preclinical model of moderate dopamine depletion

Levels of the opioid peptide dynorphin, an endogenous ligand selective for kappa-opioid receptors (KORs), its mRNA and pro-peptide precursors are differentially dysregulated in Parkinsons disease (PD) and following the development of L-DOPA-induced dyskinesia (LID). It remains unclear whether these alterations contribute to the pathophysiological mechanisms underlying PD motor impairment and the subsequent development of LID, or whether they are part of compensatory mechanisms. We sought to investigate nor-BNI, a KOR antagonist, 1) in the dopamine (DA)-depleted PD state, 2) during the development phase of LID, and 3) via measuring of tonic levels of striatal DA. While nor-BNI (3 mg/kg; s.c.) did not lead to functional restoration in the DA-depleted state, it affected the dose-dependent development of abnormal voluntary movements (AIMs) in response to escalating doses of L-DOPA in a rat PD model with a moderate striatal 6-hydroxdopamine (6-OHDA) lesion. We tested five escalating doses of L-DOPA (6, 12, 24, 48, 72 mg/kg; i.p.), and nor-BNI significantly increased the development of AIMs at the 12 and 24 mg/kg L-DOPA doses. However, after reaching the 72 mg/kg L-DOPA, AIMs were not significantly different between control and nor-BNI groups. In summary, while blocking KORs significantly increased the rate of development of LID induced by chronic, escalating doses of L-DOPA in a moderate-lesioned rat PD model, it did not contribute further once the overall severity of LID was established. While we observed an increase of tonic DA levels in the moderately lesioned dorsolateral striatum, there was no tonic DA change following administration of nor-BNI. HighlightsO_LIMild L-DOPA-induced dyskinesia develops in moderately lesioned parkinsonian rats C_LIO_LIIn the moderately-lesioned dorsolateral striatum tonic dopamine is increased C_LIO_LIAntagonizing dynorphin does not affect parkinsonian motor symptoms in rodents C_LIO_LIAntagonizing dynorphin increases rate of development of L-DOPA-induced dyskinesia C_LIO_LITonic dopamine in dorsolateral striatum is unchanged after antagonizing dynorphin C_LI

neuroscience↗

bioRxiv2023

Quantification of glutathione with high throughput live-cell imaging

Reduction oxidation (redox) reactions are central in life and altered redox state is associated with a spectrum of human diseases. Glutathione (GSH) is the most abundant antioxidant in eukaryotic cells and plays critical roles in maintaining redox homeostasis. Thus, measuring intracellular GSH level is an important method to assess the redox state of organism. The currently available GSH probes are based on irreversible chemical reactions with glutathione and cant monitor the real-time glutathione dynamics. Our group developed the first reversible reaction based fluorescent probe for glutathione, which can measure glutathione levels at high resolution using a confocal microscope and in the bulk scale with a flow cytometry. Most importantly it can quantitatively monitor the real-time GSH dynamics in living cells. Using the 2nd generation of GSH probe, RealThiol (RT), this study measured the GSH level in living Hela cells after treatment with varying concentrations of DL-Buthionine sulfoximine (BSO) which inhibits GSH synthesis, using a high throughput imaging system, Cytation 5 cell imaging reader. The results revealed that GSH probe RT at the concentration of 2.0 {micro}M accurately monitored the BSO treatment effect on GSH level in the Hela cells. The present results demonstrated that the GSH probe RT is sensitive and precise in GSH measurement in living cells at a high throughput imaging platform and has the potential to be applied to any cell lines.

biochemistry↗

bioRxiv2023

A Highly Efficient Aorta-Gonad-Mesonephros-Like Definitive Hemogenic Endothelium From Human Pluripotent Stem Cells

Summary/AbstractHuman pluripotent stem cells are a tremendous tool to model early human development and disease including their use in the in vitro generation of blood cell fates. Hematopoietic progenitors and stem cells are the primary source of blood and the immune system from early development to adulthood and arise through successive waves of hemogenic mesoderm either in the yolk sac or embryo proper. Researchers have long sought a tractable human model for observing and distinguishing these waves of hematopoiesis in the dish for human developmental and disease modeling. Here we report a high-efficiency method for differentiating human pluripotent stem cells into an aorta-gonad-mesonephros-like definitive hemogenic mesoderm capable of giving rise to definitive hematopoietic progenitor and stem cells. The hematopoietic progenitor and stem cells exhibit robust multilineage in vitro colony forming potential. Gene expression analysis and single cell sequencing strongly support the developmental timing and notion that the pluripotent stem cell derived hematopoietic stem and progenitors are strikingly like bone fide hematopoietic stem cells. The hematopoietic progenitors can be subsequently differentiated into polarized macrophage and T-cells in vitro. Minimal silencing was observed upon differentiation of the pluripotent stem cells to hematopoietic lineages when conducting gene editing. Finally, upon engraftment into immunodeficient animals the hematopoietic progenitors and stem cells differentiate into multiple lineages including B-cells, T-cells, NK-cells, and monocytes.

developmental biology↗

bioRxiv2023

MSModDetector: A Tool for Detecting Mass Shifts and Post-Translational Modifications in Individual Ion Mass Spectrometry Data

MotivationPost-translational modifications (PTMs) on proteins regulate protein structures and functions. A single protein molecule can possess multiple modification sites that can accommodate various PTM types, leading to a variety of different patterns, or combinations of PTMs, on that protein. Different PTM patterns can give rise to distinct biological functions. To facilitate the study of multiple PTMs, top-down mass spectrometry (MS) has proven to be a useful tool to measure the mass of intact proteins, thereby enabling even widely separated PTMs to be assigned to the same protein molecule and allowing determination of how many PTMs are attached to a single protein. ResultsWe developed a Python module called MSModDetector that studies PTM patterns from individual ion mass spectrometry (I MS) data. I MS is an intact protein mass spectrometry approach that generates true mass spectra without the need to infer charge states. The algorithm first detects and quantifies mass shifts for a protein of interest and subsequently infers potential PTM patterns using linear programming. The algorithm is evaluated on simulated I MS data and experimental I MS data for the tumor suppressor protein p53. We show that MSModDetector is a useful tool for comparing a proteins PTM pattern landscape across different conditions. An improved analysis of PTM patterns will enable a deeper understanding of PTM-regulated cellular processes. AvailabilityThe source code is available at https://github.com/marjanfaizi/MSModDetector together with the scripts used for analyses and to generate the figures presented in this study.

bioinformatics↗

bioRxiv2023

Analysis of the heterogeneity and complexity of murine extraorbital lacrimal gland via single-cell RNA sequencing

PurposeThe lacrimal gland is essential for maintaining ocular surface health and avoiding external damage by secreting the aqueous layer of the tear film. However, a healthy lacrimal glands inventory of cell types and heterogeneity remains understudied. MethodsHere, 10X genome-based single-cell RNA sequencing was used to generate an unbiased classification of cellular diversity in the extraorbital lacrimal gland (ELG) of C57BL/6J mice. From 48,077 high-quality cells, an atlas of cell heterogeneity was produced, and cell types were defined by classic marker genes. The possible functions of these cells and the pseudotime trajectories for certain cell populations were analyzed through bioinformatics. In addition, a preliminary analysis of the cell-cell communication network in ELG was performed. ResultsOver 41 subclasses of cells were identified, including 9 kinds of glandular epithelial cells, 7 kinds of fibroblasts, 10 kinds of myeloid-derived immune cells, at least 10 kinds of lymphoid-derived immune cells, 3 kinds of vascular-associated cell subsets, and 2 kinds of Schwann cells. Analysis of cell-cell communication networks revealed that innate lymphoid cells were closely associated with other cells. ConclusionsThis study provides the first comprehensive transcriptome atlas and related database of mouse ELG. This resource can aid in a deeper understanding of lacrimal gland biology and pathophysiology of its related diseases.

bioinformatics↗

bioRxiv2023

The histone demethylase KDM5C controls female bone mass by promoting energy metabolism in osteoclasts

Women experience osteoporosis at higher rates than men. Aside from hormones, the mechanisms driving sex-dependent bone mass regulation are not well-understood. Here, we demonstrate that the X-linked H3K4me2/3 demethylase KDM5C regulates sex-specific bone mass. Loss of KDM5C in hematopoietic stem cells or bone marrow monocytes (BMM) increases bone mass in female but not male mice. Mechanistically, loss of KDM5C impairs the bioenergetic metabolism resulting in impaired osteoclastogenesis. Treatment with the KDM5 inhibitor reduces osteoclastogenesis and energy metabolism of both female mice and human monocytes. Our report details a novel sex-dependent mechanism for bone homeostasis, connecting epigenetic regulation to osteoclast metabolism, and positions KDM5C as a target for future treatment of osteoporosis in women. One-Sentence SummaryKDM5C, an X-linked epigenetic regulator, controls female bone homeostasis by promoting energy metabolism in osteoclasts.

cell biology↗

bioRxiv2023

Neurovascular Coupling is Required for Amygdala Neuronal Activation and Associated Emotional Behaviors in Mice, Depending on NMDA Receptor Subunit 2D-expressing Cerebral Arteriolar Smooth Muscle Cells

Emotion induces changes in regional cerebral blood flow (CBF), a manifestation of neurovascular coupling (NVC), yet whether NVC might feed back to modulate emotion actively remains unexplored. Here, we demonstrate that NVC actively and bidirectionally modulates stress-induced negative emotions. We established bidirectional manipulations of NVC in freely moving mice by employing integrated pharmacological, genetic, and arteriolar optogenetic approaches. Our results showed that both systemic and basolateral amygdala (BLA) region-specific NVC deficiencies heightened emotional responses when mice transitioned from a safe, familiar environment to anxiogenic environments, and local restoration of NVC in the BLA normalized these responses. Mechanistically, NVC dysfunction impairs the capacity of BLA neuronal scaling during state transitions, manifesting as a characteristic biphasic pattern of c-Fos topology. Namely, the NVC-deficient animal aberrantly adopts high-stress configurations under mild stress but regresses to low-stress templates during high-demand survival threats, thereby compromising defensive sustainability. Notably, the genetic NVC-enhancement model counteracts NVC impairments caused by chronic stress, thereby alleviating stress-driven emotional distress. These findings established NVC in the BLA as an allostatic program that fine-tunes neural circuit activity for emotional responses, with implications for understanding and treating emotional disorders.

neuroscience↗

bioRxiv2022

Searching across-cohort relatives via encrypted genotype regression

Explicitly sharing individual level data in genomics studies has many merits comparing to sharing summary statistics, including more strict QCs, common statistical analyses, relative identification and improved statistical power in GWAS, but it is hampered by privacy or ethical constraints. In this study, we developed encG-reg, a regression approach that can detect relatives of various degrees based on encrypted genomic data, which is immune of ethical constraints. The encryption properties of encG-reg are based on the random matrix theory by masking the original genotypic matrix without sacrificing precision of individual-level genotype data. We established a connection between the dimension of a random matrix, which masked genotype matrices, and the required precision of a study for encrypted genotype data. encG-reg has false positive and false negative rates equivalent to sharing original individual level data, and is computationally efficient when searching relatives. We split the UK Biobank into their respective centers, and then encrypted the genotype data. We observed that the relatives estimated using encG-reg was equivalently accurate with the estimation by KING, which is a widely used software but requires original genotype data. In a more complex application, we launched a finely devised multi-center collaboration across 5 research institutes in China, covering 9 cohorts of 54,092 GWAS samples. encG-reg again identified true relatives existing across the cohorts with even different ethnic backgrounds and genotypic qualities. Our study clearly demonstrates that encrypted genomic data can be used for data sharing without loss of information or data sharing barrier. Author SummaryEstimating pairwise genetic relatedness within a single cohort is straightforward. However, in practice, related samples are often distributed across different cohorts, making it challenging to estimate inter-cohort relatedness. In this study, we propose a method called encrypted genotype regression (encG-reg), which provides an unbiased estimation of inter-cohort relatedness using encrypted genotypes. The genotype matrix of each cohort is masked by a random matrix, which acts similarly to a private key in a cryptographic scheme. This masking process produces encrypted genotypes, which are a projection of the original genotype matrix. We derive the expectation and particularly the sampling variance for encG-reg, the latter involves eighth-order moments calculation. encG-reg allows us to accurately identify relatedness across cohorts, even for large-scale biobank data. To demonstrate the efficacy of encG-reg, we verified it in a multi-ethnicity UK Biobank dataset comprising 485,158 samples. For this case, we successfully tracked down to the 1st-degree relatedness (such as full sibs and parent-offspring). Furthermore, we used encG-reg in a collaboration involving 9 Chinese cohorts, encompassing a total of 54,092 samples from 5 genomic centers. It is worth noting that if the number of effective markers is sufficient encG-reg has the potential to detect even more distant degrees of relatedness beyond what we demonstrated.

genetics↗

bioRxiv2022

SREBP1 activation contributes to fatty acid accumulations in necroptosis

Necroptosis is a type of programmed cell death. It is characterized by membrane permeabilization and is associated with a strong inflammatory response due to the release of intracellular components due to compromised membrane integrity. We recently showed that the accumulation of very long chain fatty acids (VLCFAs) contributes to membrane permeabilization during necroptosis. However, the mechanisms that result in the accumulation of these cytotoxic lipids remain unknown. Using comparative transcriptomics, we found that sterol regulatory element-binding protein 1 (SREBP1) is activated and that its downstream gene targets result in the accumulation of VLCFAs during necroptosis. We demonstrated that activation of SREBP1 during necroptosis exacerbates cell death. On the contrary, inactivation of SREBP1 reversed the accumulation of VLCFAs, and restored cell death and membrane permeabilization during necroptosis. Collectively, our results highlight a role for SREBP1 in regulating lipid changes during necroptosis and suggest SREBP1 as a potential target for therapeutics to reduce membrane permeabilization during necroptosis.

cell biology↗

bioRxiv2022

The role and mechanism of NRF2 in endothelial cells and smooth muscle cells of pulmonary artery

Pulmonary hypertension (PH) is a kind of fatal disease. There are no existing drugs that could reverse the diseas. NF-E2-related factor 2 (NRF2) is one of the most important moleculars in the range of cell protection. We examined the expression of NRF2 in PH models and explored the role of NRF2 in regulating abnormal phenotypes in pulmonary artery cells. We determined the expression level of NRF2 in lung tissues of PH model decreased significantly. We found that NRF2 was reduced in rat pulmonary artery endothelial cells (rPAEC) under hypoxia, while it was overexpressed in rat pulmonary artery smooth muscle cells (rPASMC) under hypoxia. Next, the results showed that knockdown NRF2 in rPAEC promoted endothelial-mesenchymal transformation and upregulated reactive oxygen species level. After the rPASMC was treated with siRNA or activator, we found that NRF2 could promote cell proliferation by regulating PDGFR/ERK1/2 and mTOR/P70S6K pathways, and accelerate cell migration by affecting MMP2/3/7. Therefore, the study suggests that the combination of NRF2 activators should be considered to eliminate the promoting effect of NRF2 activators on proliferation and migration of rPASMC. Summary statementHypoxia regulates NRF2 in PAECs and PASMCs differently. We found that NRF2 could promote cell proliferation by regulating PDGFR/ERK1/2 and mTOR/P70S6K pathways, and accelerate cell migration by affecting MMP2/3/7.

cell biology↗

bioRxiv2022

Human iPSC-derived neuron of 16p11.2 deletion reveals haplotype-specific expression of MAPK3 and its contribution to variable NDD phenotypes

Recurrent proximal 16p11.2 deletion (16p11.2del) is risk factor of diverse neurodevelopmental disorders (NDDs) with variable penetrance. Although previous human induced pluripotent stem cell (hiPSC) models of 16p11.2del confirmed disrupted neuron development, it is not known which gene(s) at this interval are mainly responsible for the abnormal cellular phenotypes and how the NDD penetrance is regulated. After haplotype phasing of 16p11.2 region, we generated hiPSCs for two 16p11.2del families with distinct residual haplotypes and variable NDD phenotypes. We also differentiated the hiPSCs to cortical neural cells and demonstrated MAPK3 as a driver signal of 16p11.2 region contributing to the dysfunctions in multiple pathways related to neuron development, which leads to altered morphological or electrophysiological properties in neuron cells. Furthermore, residual haplotype-specific MAPK3 expression was identified in 16p11.2del neuron cells, associating MAPK3 down-expression with the minor allele of the residual haplotype. Ten SNPs of the residual haplotype are mapped as enhancer SNPs (enSNPs) of MAPK3, eight enSNPs were functionally validated by luciferase assays, implying enSNPs contribute to residual haplotype-specific MAPK3 expression via cis-regulation. Finally, the analyses of three different patient cohorts showed that the residual haplotype of 16p11.2del is associated with variable NDD phenotypes.

genetics↗

bioRxiv2022

Respiratory mucosal vaccination of peptide-poloxamine-DNA nanoparticles provides complete protection against lethal SARS-CoV-2 challenge

The ongoing SARS-CoV-2 pandemic represents a brutal reminder of the continual threat of mucosal infectious diseases. Mucosal immunity may provide robust protection at the predominant sites of SARS-CoV-2 infection. However, it remains unclear whether respiratory mucosal administration of DNA vaccines could confer protective immune responses against SARS-CoV-2 challenge due to the insurmountable barriers posed by the airway. Here, we applied self-assembled peptide-poloxamine nanoparticles with mucus-penetrating properties for pulmonary inoculation of a COVID-19 DNA vaccine (pSpike/PP-sNp). Not only displays the pSpike/PP-sNp superior gene-transfection and favorable biocompatibility in the mouse airway, but pSpike/PP-sNp promotes a tripartite immunity consisting of systemic, cellular and mucosal immune responses that are characterized by mucosal IgA secretion, high levels of neutralizing antibodies, and resident memory phenotype T-cell responses in the lungs of mice. Most importantly, pSpike/PP-sNp completely eliminates SARS-CoV-2 infection in both upper and lower respiratory tracts and enables 100% survival rate of mice following lethal SARS-CoV-2 challenge. Our findings indicate PP-sNp might be a promising platform in mediating DNA vaccines to elicit all-around mucosal immunity against SARS-CoV-2.

immunology↗

bioRxiv2022

MEK inhibitor resistance in lung cancer cells associated with addiction to sustained ERK suppression

MEK inhibitors have yielded limited efficacy in KRAS-mutant lung adenocarcinoma (LUAD) patients due to drug resistance. We established trametinib-resistant KRAS-mutant LUAD cells and describe a state of "drug addiction" in a subset of resistant cases where cells are dependent on trametinib for survival. Dependence on ERK2 suppression underlies this phenomenon whereby trametinib removal hyperactivates ERK and results in ER stress and apoptosis. Amplification of KRASG12C occurs in drug-addicted cells and blocking mutant specific activity with AMG 510 rescues the lethality after trametinib withdrawal. Furthermore, increased KRASG12C expression is lethal to other KRAS mutant LUAD cells, consequential to ERK hyperactivation. Our study represents the first instance of this phenotype associated with KRAS amplification and demonstrates that acquired genetic changes that develop in the background of MAPK suppression can have unique consequence. We suggest that the presence of mutant KRAS amplification in patients may identify those that may benefit from a "drug holiday" to circumvent drug resistance. These findings demonstrate the toxic potential of hyperactive ERK signaling and highlight potential therapeutic opportunities in patients bearing KRAS mutations.

cancer biology↗