Biology subjects

Lee, K. S.

Publications and source records attributed to Lee, K. S..

11 recordsLinked to original sources

bioRxiv2025

Profile of proteins involved in iron homeostasis and energy metabolism in multiple organs of leptin-deficient mice

Obesity is a global health problem. Its impacts are even more alarming when consider associated comorbidities, which include iron deficiency. Despite the importance of iron in metabolic function, the relationship between iron deficiency and metabolic dysregulation in obesity has not been fully addressed. Here, we evaluated the proteins involved in iron homeostasis and metabolism in multiple organs of leptin-deficient obese mice, a model that allows investigation of the progression of obesity. In the liver, proteins involved in glycaemia control were altered in both 3- and 5-month-old ob/ob mice (3mOB and 5mOB), but intracellular iron storage was reduced only in 3mOB. In the serum samples, glucose and cholesterol were increased in both 3mOB and 5mOB, with no alterations in iron markers. The pattern of liver proteins and serum metabolites indicate insulin-resistance state and glycemia dysregulation. In adipose tissue, 3mOB showed increased citrate synthase levels, while 5mOB showed increased MTCO2 and reduced ATP synthase levels. Ferritin was increased only in 5mOB. In the hippocampus, one of the most affected brain regions in obesity, increased MTCO2 and reduced ATP synthase levels were observed in 3mOB, while in 5mOB, increased OXCT1, a key enzyme for ketone body utilization, was observed. Reduction of ferritin levels was observed only in 5mOB. Thus, at 5 months, when the animals develop severe obesity, iron accumulates in adipose tissue but shows a reduction in the hippocampus. Our findings suggest that iron homeostasis is disrupted in a tissue-specific manner, with altered protein profiles that indicate metabolic dysregulation in multiple organs.

biochemistry↗

bioRxiv2024

Intratumoral administration of mRNA-1273 vaccine delays melanoma growth in mice

BackgroundImmunotherapies are advantageous for treating cancers; however, their efficacy is limited in unresponsive hosts with "cold" tumor microenvironments. This limitation primarily stems from the lack of infiltrating CD8+ T cells, which are major effectors of the anti-cancer immune response. Here, we demonstrate the effects of intratumoral (IT) injections of the COVID-19 mRNA vaccine on the impairment of tumor growth in mice. MethodsEstablished B16F10 subcutaneous tumor models in wild type mice were used to evaluate the tumor response from IT administration of mRNA-1273. We compared treatment outcomes, immune composition, and transcriptomic effects from mRNA-1273 using survival studies, intravital imaging, flow cytometry, single-cell RNA sequencing, and abscopal studies. The ability of mRNA-1273 to enhance immune checkpoint therapy response was also evaluated. ResultsTumor growth and survival studies following a single IT injection of the COVID-19 mRNA-1273 vaccine showed significant tumor suppression and prolonged survival in tumor-bearing mice. mRNA-1273 treatment resulted in a significant increase in CD8+ T cell infiltration into the tumor microenvironment, as observed using intravital imaging and flow cytometry. Further tumor growth suppression was achieved using additional mRNA-1273 treatments. Combination administration of mRNA-1273 with immune checkpoint therapies demonstrated enhanced effects, further delaying tumor growth and improving the survival time of tumor-bearing mice. ConclusionIT injection of mRNA-1273 significantly reduced tumor growth and enhanced CD8+ T cells in the tumor microenvironment. Tumor suppression was further enhanced following multiple injections of mRNA-1273 or when combined with immune checkpoint therapies. This study demonstrates that mRNA vaccines may be used as adjuvants for immunotherapies. What is already known on this topicO_LIMost cancer patients develop adequate antibody response to vaccination with mRNA-1273 and produce spike-specific T cell responses. However, it is unclear if the mRNA-1273 vaccine can be used to elicit anti-tumor T cell responses. C_LI What this study addsO_LIIntratumoral injection of mRNA-1273 significantly delayed melanoma growth. C_LIO_LITreatment with mRNA-1273 significantly increased CD8+ T cell infiltration into the tumor microenvironment. C_LIO_LIEnhanced effects of combination mRNA-1273 and immune checkpoint therapy in anti-tumor immunity. C_LI How this study might affect research, practice, or policyO_LImRNA vaccine may be an effective adjuvant with immune checkpoint therapy. C_LI

immunology↗

bioRxiv2024

Exploiting WEE1 kinase activity as FUS::DDIT3-dependent therapeutic vulnerability in myxoid liposarcoma

The pathognomonic FUS::DDIT3 fusion protein drives myxoid liposarcoma (MLS) tumorigenesis via aberrant transcriptional activation of oncogenic signaling. Since FUS::DDIT3 has so far not been pharmacologically tractable to selectively target MLS cells, this study investigated the functional role of the cell cycle regulator WEE1 as novel FUS::DDIT3-dependent therapeutic vulnerability in MLS. Here we demonstrate that enhanced WEE1 pathway activity represents a hallmark of FUS::DDIT3-expressing cell lines as well as MLS tissue specimens and that WEE1 is required for MLS cellular survival in vitro and in vivo. Pharmacologic inhibition of WEE1 activity results in DNA damage accumulation and cell cycle progression forcing cells to undergo apoptotic cell death. In addition, our results uncover FUS::DDIT3-dependent WEE1 expression as an oncogenic survival mechanism to tolerate high proliferation and resulting replication stress in MLS. Fusion protein-driven G1/S cell cycle checkpoint deregulation via overactive Cyclin E/CDK2 complexes thereby contributes to enhanced WEE1 inhibitor sensitivity in MLS. These findings identify WEE1-mediated replication stress tolerance as molecular vulnerability in FUS::DDIT3-driven MLS tumorigenesis that could represent a novel target for therapeutic intervention.

cancer biology↗

bioRxiv2024

Mechanism of bacterial predation via ixotrophy

Predation allows bacteria to access alternative substrates in low-nutrient conditions. Ixotrophy has been proposed as a predatory lifestyle of multicellular filamentous bacteria in aquatic environments; however, the molecular mechanism remains unknown. Here we uncover by a multidisciplinary approach that ixotrophy requires the interplay of multiple cellular machineries and a regulatory mechanism. Attacker-prey contacts are established by gliding motility and extracellular grappling hook-like structures that bind prey flagella. Cryo-electron microscopy identifies the grappling hooks as a heptameric assembly of a Type 9 Secretion System substrate. Cryo-electron tomography and functional assays show that killing is mediated by puncturing of the prey cell using a Type 6 Secretion System, possibly triggered by extracellular antennae. Single-cell analyses with stable isotope-labeled prey demonstrate that prey components are taken up by the attacker. Depending on nutrient availability, ixotrophy is switched off by endogenous Insertion Sequence Elements and re-activated through their excision. A marine metagenomic time series provides evidence for coupled dynamics of ixotrophic bacteria and their prey. Our study reveals the complex mechanism of a conserved microbial predatory lifestyle and indicates the need for its regulation in conditions where the expression of costly pathways is dispensable.

microbiology↗

bioRxiv2023

Three-dimensional virtual H&E staining of label-free colon cancer tissue using holotomography and deep learning

In standard histopathology, hematoxylin and eosin (H&E) staining stands as a pivotal tool for cancer tissue analysis. However, this method is limited to two-dimensional (2D) analysis or requires labor-intensive preparation for three-dimensional (3D) inspection of cancer tissues. In this study, we present a method for 3D virtual H&E staining of label-free cancer tissues, employing holotomography and deep learning. Holotomography is used to measure the 3D refractive index (RI) distribution of the label-free cancer slides. A deep learning-based image-to-image translation framework is integrated into the resulting 3D RI distribution, enabling virtual H&E staining in 3D. Our method has been applied to colon cancer tissue slides with thicknesses up to 20 m, with conventional chemical H&E staining providing a direct validation for the method. This framework not only bypasses the conventional staining process but also provides 3D structures of glands, lumens, and individual nuclei. The results demonstrate enhancement in histopathological efficiency and the extension of the standard histopathology into the 3D realm. To validate the repeatability and scalability of the approach, we applied the framework to the gastric cancer slides obtained from different institute and imaging devices.

cancer biology↗

bioRxiv2023

Stratification of enterochromaffin cells by single-cell expression analysis

Dynamic interactions between gut mucosal cells and the external environment are essential to maintain gut homeostasis. Enterochromaffin (EC) cells transduce both chemical and mechanical signals and produce 5-hydroxytryptamine (5-HT) to mediate disparate physiological responses. However, the molecular and cellular basis for functional diversity of ECs remains to be adequately defined. Here, we integrated single-cell transcriptomics with spatial image analysis to identify fourteen EC clusters that are topographically organized along the gut. Subtypes predicted to be sensitive to the chemical environment and mechanical forces were identified that express distinct transcription factors and hormones. A Piezo2+ population in the distal colon was endowed with a distinctive neuronal signature. Using a combination of genetic, chemogenetic and pharmacological approaches, we demonstrated Piezo2+ ECs are required for normal colon motility. Our study constructs a molecular map for ECs and offers a framework for deconvoluting EC cells with pleiotropic functions.

cell biology↗

bioRxiv2023

Intranasal VLP-RBD vaccine adjuvanted with BECC470 confers immunity against Delta SARS-CoV-2 challenge in K18-hACE2-mice

As the COVID-19 pandemic transitions to endemic, seasonal boosters are a plausible reality across the globe. We hypothesize that intranasal vaccines can provide better protection against asymptomatic infections and more transmissible variants of SARS-CoV-2. To formulate a protective intranasal vaccine, we utilized a VLP-based platform. Hepatitis B surface antigen- based virus like particles (VLP) linked with receptor binding domain (RBD) antigen were paired with the TLR4-based agonist adjuvant, BECC 470. K18-hACE2 mice were primed and boosted at four-week intervals with either VLP-RBD-BECC or mRNA-1273. Both VLP-RBD-BECC and mRNA-1273 vaccination resulted in production of RBD-specific IgA antibodies in serum. RBD- specific IgA was also detected in the nasal wash and lung supernatants and were highest in VLP-RBD-BECC vaccinated mice. Interestingly, VLP-RBD-BECC vaccinated mice showed slightly lower levels of pre-challenge IgG responses, decreased RBD-ACE2 binding inhibition, and lower neutralizing activity in vitro than mRNA-1273 vaccinated mice. Both VLP-RBD-BECC and mRNA-1273 vaccinated mice were protected against challenge with a lethal dose of Delta variant SARS-CoV-2. Both vaccines limited viral replication and viral RNA burden in the lungs of mice. CXCL10 is a biomarker of severe SARS-CoV-2 infection and we observed both vaccines limited expression of serum and lung CXCL10. Strikingly, VLP-RBD-BECC when administered intranasally, limited lung inflammation at early timepoints that mRNA-1273 vaccination did not. VLP-RBD-BECC immunization elicited antibodies that do recognize SARS-CoV-2 Omicron variant. However, VLP-RBD-BECC immunized mice were protected from Omicron challenge with low viral burden. Conversely, mRNA-1273 immunized mice had low to no detectable virus in the lungs at day 2. Together, these data suggest that VLP-based vaccines paired with BECC adjuvant can be used to induce protective mucosal and systemic responses against SARS- CoV-2.

immunology↗

bioRxiv2022

Molecular engineering of a cryptic epitope in Spike RBD improves manufacturability and neutralizing breadth against SARS-CoV-2 variants

There is a continued need for sarbecovirus vaccines that can be manufactured and distributed in low- and middle-income countries (LMICs). Subunit protein vaccines are manufactured at large scales at low costs, have less stringent temperature requirements for distribution in LMICs, and several candidates have shown protection against SARS-CoV-2. We previously reported an engineered variant of the SARS-CoV-2 Spike protein receptor binding domain antigen (RBD-L452K-F490W; RBD-J) with enhanced manufacturability and immunogenicity compared to the ancestral RBD. Here, we report a second-generation engineered RBD antigen (RBD-J6) with two additional mutations to a hydrophobic cryptic epitope in the RBD core, S383D and L518D, that further improved expression titers and biophysical stability. RBD-J6 retained binding affinity to human convalescent sera and to all tested neutralizing antibodies except antibodies that target the class IV epitope on the RBD core. K18-hACE2 transgenic mice immunized with three doses of a Beta variant of RBD-J6 displayed on a virus-like particle (VLP) generated neutralizing antibodies (nAb) to nine SARS-CoV-2 variants of concern at similar levels as two doses of Comirnaty. The vaccinated mice were also protected from challenge with Alpha or Beta SARS-CoV-2. This engineered antigen could be useful for modular RBD-based subunit vaccines to enhance manufacturability and global access, or for further development of variant-specific or broadly acting booster vaccines.

bioengineering↗

bioRxiv2022

SARS-CoV-2 Delta variant induces enhanced pathology and inflammatory responses in K18-hACE2 mice

The COVID-19 pandemic has been fueled by novel variants of concern (VOC) that have increased transmissibility, receptor binding affinity, and other properties that enhance disease. The goal of this study is to characterize unique pathogenesis of the Delta VOC strain in the K18-hACE2-mouse challenge model. Challenge studies suggested that the lethal dose of Delta was higher than Alpha or Beta strains. To characterize the differences in the Delta strains pathogenesis, a time-course experiment was performed to evaluate the overall host response to Alpha or Delta variant challenge. qRT-PCR analysis of Alpha- or Delta- challenged mice revealed no significant difference between viral RNA burden in the lung, nasal wash or brain. However, histopathological analysis revealed high lung tissue inflammation and cell infiltration following Delta- but not Alpha-challenge at day 6. Additionally, pro-inflammatory cytokines were highest at day 6 in Delta-challenged mice suggesting enhanced pneumonia. Total RNA-sequencing analysis of lungs comparing infected to uninfected mice revealed that Alpha-challenged mice have more total genes differentially activated, conversely, Delta-challenged mice have a higher magnitude of differential gene expression. Delta-challenged mice have increased interferon-dependent gene expression and IFN-{gamma} production compared to Alpha. Analysis of TCR clonotypes suggested that Delta challenged mice have increased T-cell infiltration compared to Alpha challenged. Our data suggest that Delta has evolved to engage interferon responses in a manner that may enhance pathogenesis. The in vivo and in silico observations of this study underscore the need to conduct experiments with VOC strains to best model COVID-19 when evaluating therapeutics and vaccines. ImportanceThe Delta variant of SARS-CoV-2 is known to be more transmissible and cause severe disease in human hosts due to mutations in its genome that are divergent from previous variants of concern (VOC). Our study evaluates the pathogenesis of Delta in the K18-hACE2 mouse model compared to the Alpha VOC. We observed that relative to Alpha, Delta challenge results in enhanced inflammation and tissue damage with stronger antiviral responses. These observations provide insight into Deltas unique pathogenesis.

immunology↗

bioRxiv2022

Systematic Review and Meta-Analysis: Task-based fMRI Studies in Youths with Irritability

ObjectiveChildhood irritability, operationalized as disproportionate and frequent temper tantrums and low frustration tolerance relative to peers, is a transdiagnostic symptom across many pediatric disorders. Studies using task-dependent functional magnetic resonance imaging (fMRI) to probe neural dysfunction in irritability have increased. However, an integrated review summarizing the published methods and synthesized fMRI results remains lacking. MethodWe conducted a systematic search using irritability terms and task functional neuroimaging in key databases in March 2021, and identified 30 studies for our systematic review. Sample characteristics and fMRI methods were summarized. A subset of 28 studies met the criteria for extracting coordinate-based data for quantitative meta-analysis. Ten activation-likelihood estimations were performed to examine neural convergence across irritability measures and fMRI task domains. ResultsSystematic review revealed small sample sizes (median = 58, mean age range = 8-16 years) with heterogeneous sample characteristics, irritability measures, tasks, and analytical procedures. Meta-analyses found no evidence for neural activation convergence of irritability across neurocognitive functions related to emotional reactivity, cognitive control, and reward processing, nor within each domain. Sensitivity analyses partialing out variances driven by heterogeneous tasks, irritability measures, stimulus types, and developmental ages all yielded null findings. ConclusionThe lack of neural convergence suggests a need for common, standardized irritability assessments and more homogeneous fMRI tasks. Thoughtfully designed fMRI studies probing commonly defined neurocognitive functions may be more fruitful to elucidate the neural mechanisms of irritability. Open science practices, data mining in large neuroscience databases, and standardized analytical methods promote meaningful collaboration in irritability research.

neuroscience↗

bioRxiv2021

SARS-CoV-2 B.1.1.7 and B.1.351 variants of concern induce lethal disease in K18-hACE2 transgenic mice despite convalescent plasma therapy

SARS-CoV-2 variants of concern (VoCs) are impacting responses to the COVID-19 pandemic. Here we present a comparison of the SARS-CoV-2 USA-WA1/2020 (WA-1) strain with B.1.1.7 and B.1.351 VoCs and identify significant differences in viral propagation in vitro and pathogenicity in vivo using K18-hACE2 transgenic mice. Passive immunization with plasma from an early pandemic SARS-CoV-2 patient resulted in significant differences in the outcome of VoC-infected mice. WA-1-infected mice were protected by plasma, B.1.1.7-infected mice were partially protected, and B.1.351-infected mice were not protected. Serological correlates of disease were different between VoC-infected mice, with B.1.351 triggering significantly altered cytokine profiles than other strains. In this study, we defined infectivity and immune responses triggered by VoCs and observed that early 2020 SARS-CoV-2 human immune plasma was insufficient to protect against challenge with B.1.1.7 and B.1.351 in the mouse model.

microbiology↗