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Kim, B.

Publications and source records attributed to Kim, B..

At least 55 records · Page 3Linked to original sources

Localized immunomodulation with cytokine-producing cells to mitigate host immune rejection responses in rodents and a non-human primate

The efficacy of cell-based therapeutics is often compromised by host immune recognition of implanted cells and biomaterials, resulting in fibrotic encapsulation and loss of function. Here, we address this challenge with an immunomodulatory cell-based therapy, in which alginate-encapsulated retinal pigment epithelial cells continuously secrete cytokines to locally modulate the implant microenvironment. In a healthy rodent model, the localized production of interleukin-10 (IL-10) or IL-12 from encapsulated cytokine-producing cells prevented host immune rejection and fibrosis of alginate capsules. Mechanistically, treatment was associated with reduced expression of pro-fibrotic genes and immune shifts consistent with macrophage and T-cell regulation, supporting a cytokine-mediated mitigation of foreign body response. In a diabetic murine model (streptozotocin-induced C57BL/6J), co-implantation of human islets with IL-10-producing cells attenuated pericapsular fibrosis, preserved islet viability, and restored normoglycemia for up to 100 days (4.76 times longer than islets alone). Significantly, IL-10-producing cells were also effective in enabling the durability and function of encapsulated cells in a healthy non-human primate, showing translational feasibility. Collectively, these findings suggest that localized cytokine delivery can reduce fibrotic encapsulation and support durable graft function, offering a path to lessen reliance on systemic immunosuppression in islets transplantation and other implantable biomaterial therapies. TeaserEncapsulated IL-10-producing cells locally suppress fibrosis and extend graft function in rodent models and a non-human primate.

bioengineering↗

NGN2 Expression and Regional Patterning Allow Rapid Differentiation from hiPSCs to DRG-Like Neurons Responsive to Type 2 Cytokines

Itch or pruritus, is a sensation that elicits scratching behaviour and is a major symptom and cause of morbidity in skin diseases such as atopic dermatitis (AD), allergic contact dermatitis (ACD), prurigo nodularis (PN), and urticaria. Itch is often triggered by inflammatory stimuli in the skin including type 2 cytokines such as IL-4, IL-13, and/or IL-31. Several therapies targeting type 2 immune pathways have been developed to treat pruritus; however, itch improvement in many patients remains to be improved. Thus, additional approaches to modulate sensory neuron activity are needed. Ex vivo or even in vitro study of the molecular mechanisms underlying primary sensory neuron activation is challenging since harvesting neurons from dorsal root ganglia (DRG) in patients can only be done from cadavers. Herein, we describe rapid human sensory neurons generation (2 days to precursor cells) by in vitro differentiation of human induced pluripotent stem cells (hiPSC) from simultaneous application of patterning factors with NGN2 overexpression. We show that these hiPSC-derived sensory neurons possess key characteristics of primary sensory neurons. They express key neuronal markers, such as TRKA receptors, TRPV1 and TRPA1 channels, and functionally respond to the TRPV1 agonist capsaicin. In addition, they express key type 2 cytokine receptors such as interleukin (IL)-4R and IL31-R, known to promote itch in AD and PN. Moreover, these cells are functional as our sensory neurons respond to IL-4, IL-13 and IL-31 stimulation. Collectively, these data demonstrate that our protocol generates a phenotypic profile consistent with native somatosensory neurons that can facilitate development of novel approaches to model and treat pruritic disease.

neuroscience↗

CRISPR interference in a Streptococcus agalactiae Multi-locus Sequence Type 17 Strain

Group B Streptococcus (GBS), a common colonizer of the human genital and gastrointestinal tracts, is a leading cause of neonatal bacterial meningitis, which can lead to severe neurological complications. The hypervirulent serotype III, sequence type 17 (ST-17) strain COH1 is strongly associated with late-onset disease due to its unique set of virulence factors. However, genetic manipulation of ST-17 strains is notoriously challenging, limiting the ability to study key pathogenic genes. In this study, we developed a CRISPR interference (CRISPRi) system utilizing an endogenous catalytically inactivated Cas9 (dCas9) in the COH1 strain, enabling targeted and tunable gene expression knockdown. We confirmed the efficacy of this system through hemolysis assays, qPCR transcriptional analysis, and in vitro infection models using human brain endothelial cells. The CRISPRi system successfully produced phenotypic knockdowns of essential virulence genes, including pilA, srr2, and iagA, reducing adhesion, invasion, and inflammatory responses at the blood-brain barrier. This platform enables rapid gene knockdowns for functional genomics in ST-17 GBS, enabling high-throughput screening and pathogenesis research. ImportanceGroup B Streptococcus (GBS) remains the worlds leading cause of neonatal meningitis. GBS-host interactions at the blood-brain barrier (BBB) are dependent on bacterial factors, including surface factors and two-component systems. Multi-locus sequence type 17 (ST-17) GBS strains are highly associated with neonatal meningitis, and these strains harbor many virulence factors for infection at the BBB. Historically, these factors have been studied using traditional knockout mutagenesis, which has proven challenging in the most common ST-17 lab strain, COH1. This study utilizes CRISPR interference (CRISPRi) to generate rapid expression knockdown. This study validates a CRISPRi-enabled COH1 dCas9 strain as a versatile tool for probing GBS pathogenesis at the BBB.

microbiology↗

smDeepFLUOR: Single-Molecule Deep Learning Fluorescence Classification

Fluorescence intensity variation has long served as a primary readout for monitoring biological events. However, single-fluorophore signals arising from distinct molecular events often exhibit similar intensity profiles, making further classification challenging using conventional methods. In this study, we introduce smDeepFLUOR, a deep learning-based framework that resolves seemingly homogeneous spatiotemporal fluorescence signals by uncovering latent features imperceptible to conventional analyses. By leveraging a three-dimensional convolutional neural network trained on image sequences captured over 7 x 7 x 10 voxel windows, smDeepFLUOR reliably distinguishes specific from nonspecific protein binding, even across different experimental days, with an accuracy of up to 97%. Remarkably, smDeepFLUOR also captures real-time DNA synthesis kinetics by identifying subtle changes in the spatial distance between the fluorophore and the 3 end of nascent DNA, a feature undetectable by traditional methods. These classifications were achieved without incorporating explicit physical rules or engineered features, implying the presence of intrinsic, previously unrecognized differences in emission patterns. This approach significantly extends the analytical capabilities of single-molecule fluorescence imaging and opens new avenues for minimally labeled and label-free protein activities.

biophysics↗

Human ribomes reveal DNA-embedded ribonucleotides as a new type of epigenetic mark

Ribonucleoside monophosphates (rNMPs) are abundant in DNA, but their distribution and function in human nuclear genomes remain unknown. Here, we mapped nearly one million rNMPs per genome across diverse human cell types, defining a nuclear "ribome" with non-random distribution patterns. rNMPs are enriched in C/G-rich sequences, epigenetically marked regions, and telomeres. Conserved ribonucleotide-enriched zones (REZs) overlap with CpG islands and R-loops. rNMP concentration near transcription start sites (TSSs) correlates positively with gene expression. Wild-type cells display a broader gene-expression range than ribonuclease H2A (RNH2A) knockouts, in which loss of rNMP cleavage causes pronounced retention of embedded rG and strand-biased rC near TSSs, both increasing with gene expression. These findings establish DNA-embedded rNMPs as a novel epigenetic mark that modulates human gene expression.

molecular biology↗

Bazedoxifene rescues sexually dimorphic autistic-like abnormalities in mice carrying a biallelic MDGA1 mutation

In the accompanying study, we describe two pairs of MDGA1 missense mutations (Val116Met/Ala688Val and Tyr635Cys/Glu756Gln) from two patients with autism spectrum disorders (ASDs) and how these mutations exert distinct abnormalities in biological processes during central nervous system development. Here, we generated knockin (KI) mice harboring the murine version of Tyr635Cys/Glu756Gln MDGA1 (Mdga1Y636C/E751Q) and performed extensive behavioral analyses. Male KI mouse pups and adults exhibited impaired ultrasonic vocalizations and sensorimotor gating (ASD-relevant behavioral deficits), and thus exhibited phenotypes different from those of male Mdga1 conditional knockout (cKO) mice. In contrast, adult female KI mice did not exhibit a range of ASD-like behavioral abnormalities. Electrophysiological analyses performed using both juvenile and adult Mdga1Y636C/E751Q mice revealed sexually dimorphic and developmental stage-dependent compromises of GABAergic synaptic inhibition. In addition, proteomics analyses showed that the phospho-proteomic phenotypes differed between Mdga1Y636C/E751Q and Mdga1-cKO mice. Treatment of male Mdga1Y636C/E751Q KI mice with the FDA-approved estrogen receptor modulator, bazedoxifene, restores the KI-related molecular, GABAergic synapse, and behavioral changes. Collectively, our results suggest a novel treatment strategy for ASDs that present developmentally regulated and/or sexually dimorphic features.

neuroscience↗

Adipocytes in tumour microenvironment promote chemoresistance in TNBC through oxysterols

ObjectiveTriple-negative breast cancer (TNBC) patients with excess adipose tissue experience poorer disease-free survival than those with a healthy body mass index. Adipocytes, abundant in mammary tissue, store and release cholesterol, which can be hydroxylated to form oxysterols. These cholesterol derivatives activate the liver X receptor (LXR) pathway. This study tested the hypothesis that adipocytes contribute to an imbalanced tumour-microenvironment by exposing cancer cells to elevated oxysterols, mimicking chemotherapy-exposure conditions and priming for chemoresistance. MethodsTumour tissue microarray from 148 TNBC patients was assessed using immunohistochemistry for expression of CH25H, CYP46A1, CYP27A1 and P-glycoprotein, and survival outcomes assessed. Gene expression was compared between tumours from patients and mouse models with high versus low adiposity. In vitro, cells of the tumour-microenvironment were evaluated for oxysterol content, secretion, expression of relevant enzymes, and their ability to induce P-glycoprotein expression and drug resistance in TNBC cells. ResultsIn patients, expression of oxysterol-synthesizing enzymes in stroma correlated with P-glycoprotein expression in cancer epithelial cells and was associated with shorter disease-free survival. Adipocytes conditioned media contained significantly higher oxysterols levels than that conditioned by other cell types and induced P-glycoprotein expression and drug resistance in MDA.MB.468 cells. Obese mice had elevated levels of P-glycoprotein in tumours compared to lean counterparts. ConclusionsAdipocytes secrete oxysterols that promote drug resistance in vitro and correlate with oxysterol:Pgp axis and survival in vivo. SignificanceThis study reveals a mechanism by which adipose tissue contributes to drug resistance in ER-negative breast cancers, identifying the oxysterol-Pgp axis as potential therapeutic target.

cancer biology↗

Comparative gene annotation of 304 species of Drosophilidae

High-quality genome annotations are essential if we are to address central questions in comparative genomics, such as the origin of new genes, the drivers of genome size variation, and the evolutionary forces shaping gene content and structure. Here, we present protein-coding gene annotations for 301 species of the family Drosophilidae, generated using the Comparative Annotation Toolkit (CAT) and BRAKER3, and incorporating available RNA-seq and protein evidence. We take a comparative phylogenetic approach to annotation, with the aim of improving consistency and accuracy, and to generate a robust set of gene annotations and orthology assignments. We analyze our annotations using a phylogenetic mixed-model approach and find that gene number and CDS length exhibit moderate phylogenetic heritability (40% and 9.7%, respectively). For comparison, we also present analyses using a subset of the 215 highest quality genomes, although the findings were not markedly different. Our work suggests that while evolutionary history contributes to variation in these traits, species-specific factors--including assembly error--play a substantial role in shaping observed differences. To illustrate the utility of our annotations for comparative analyses, we investigate codon usage bias and amino acid composition across Drosophilidae. We find that codon usage is correlated with overall GC content and evolves slowly, but that it is also strongly shaped by selection--such that, in general, species with the strongest selection on synonymous codon usage show the lowest GC bias in third codon positions. This comparative annotation dataset forms part of an on-going collaborative project to sequence and annotate all species of Drosophilidae, with data and annotations being made rapidly and freely available on an on-going basis. We hope that this effort will serve as a foundation for studies in evolutionary and functional genomics and comparative biology across Drosophilidae.

genomics↗

Mapping human cerebral blood flow with high-density, multi-channel speckle contrast optical spectroscopy

Recently, speckle contrast optical spectroscopy (SCOS) enabled non-invasive, high signal-to-noise-ratio (SNR) human cerebral blood flow (CBF) measurements, relevant for both neuroscience and clinical monitoring of diseases with CBF dysregulation. Single channel SCOS measurements limit the information obtained to only one location on the head. In this work, we develop a multi-channel SCOS system to map spatial heterogeneity in CBF changes during human brain activation. Using a galvanometer, we temporally multiplexed a free-space laser to 7 source fibers positioned at different locations on the head. Diffuse light collected from the tissue is captured by fiber bundles projecting to 17 complementary metal-oxide semiconductor (CMOS) cameras, resulting in 50 source-detector channels measuring optical density (OD) and relative CBF changes covering an area of 7.6 cm by 6.6 cm on the head. We validated the spatial specificity and stability of the system using a liquid flow phantom. We then measured brain activity during a word-color Stroop task in 15 subjects and obtained brain activation maps. The average signal changes in the channel showing the largest activation were 1.7 x 10-2 in {Delta}OD and 6.6% in CBF.

bioengineering↗

The graphene-based affinity cryo-EM grid for the endogenous protein structure determination

Following recent advancements in cryo-electron microscopy (cryo-EM) instrumentation and software algorithms, the next bottleneck in achieving high-resolution cryo-EM structures arises from sample preparation. To overcome this, we developed a graphene-based affinity cryo-EM grid, the Graffendor (GFD) grid, to target low-abundance endogenous protein complexes. To maintain grid quality and consistency within a single batch of 36 grids, we established a one-step crosslinking batch-production method using genetically modified ALFA nanobody as affinity probe (GFD-A grid). Using low concentrations of {beta}-galactosidase-2xALFA, we demonstrated the GFD-A grids efficiency in capturing tagged proteins and resolving its cryo-EM structure at 2.71 [A]. To test its application for endogenous proteins, we engineered yeast cells with a C-terminal tandem affinity tag (3xALFA-Tev-3xFlag: ATF) at Pop6, a shared component of RNase MRP and RNase P. Cryo-EM structures of RNase MRP and RNase P were resolved at 3.3 [A] and 3.0 [A] from cell lysates, and 3.6 [A] and 3.9 [A] from anti-flag elution, respectively. Notably, additional densities were observed in the structures obtained from cell lysates, which were absent in those from the anti-FLAG eluate. These findings establish the GFD-A grid as a robust platform for investigating endogenous proteins, capable of capturing transient interactions and enhancing the resolution of challenging cryo-EM structures with greater efficiency.

biochemistry↗

Combinatorial effects of Zingiber officinale and Citrus limon juices: Hypolipidemic and antioxidant insights from in vivo, in vitro, and in silico investigations

The combined use of Zingiber officinale (ginger) and Citrus limon (lemon) has long been valued in traditional medicine for their significant therapeutic properties, particularly in supporting cardiovascular health. However, their synergistic effects on hyperlipidemia and oxidative stress, both critical risk factors for cardiovascular diseases, remain underexplored. This study employed a multidisciplinary approach including in vivo (mice model with triton WR-1339-induced hyperlipidemia), in vitro (antioxidant assays such as DPPH and ABTS), and in silico (molecular docking targeting HMG-CoA reductase) to evaluate the hypolipidemic and antioxidant potential of ginger and lemon juices. Phytochemical analysis identified high concentrations of bioactive compounds, with ginger juice containing 6-gingerol (15.54% peak area) and lemon juice featuring hesperidin (13.85% peak area) and rutin (5.57% peak area). These compounds were instrumental in the observed pharmacological effects. The combined formulation significantly improved lipid profiles, reducing total cholesterol by 54.3%, triglycerides by 49.8%, and LDL by 58.1% while increasing HDL by 47.6% compared to hyperlipidemic controls (p < 0.05). Antioxidant assays revealed high free radical scavenging activity, with IC50 values of 30.92 {+/-} 2.00 {micro}g/mL for ABTS and 44.94 {+/-} 1.02 {micro}g/mL for DPPH in the combined formulation. Molecular docking confirmed strong binding affinities, with hesperidin and 6-gingerol showing binding energies of -10.4 kcal/mol and -9.6 kcal/mol, respectively, against HMG-CoA reductase. In conclusion, combining Zingiber officinale and Citrus limon juices demonstrates robust hypolipidemic and antioxidant effects, significantly outperforming the individual juices. These results support their potential as natural therapeutic agents for managing hyperlipidemia and oxidative stress. Further clinical studies are recommended to validate these promising findings and explore their application in nutraceutical development.

pharmacology and toxicology↗

Light-activated tetanus neurotoxin for conditional proteolysis and inducible synaptic inhibition in vivo

The light chain of tetanus neurotoxin (TeNT) is a 52 kD metalloprotease that potently inhibits synaptic transmission by cleaving the endogenous vesicle fusion protein VAMP2. To mitigate the toxicity of TeNT and harness it as a conditional tool for neuroscience, we engineered Light-Activated TeNT (LATeNT) via insertion of the light-sensitive LOV domain into an allosteric site. LATeNT was optimized by directed evolution and shown to have undetectable activity in the dark mammalian brain. Following 30 seconds of weak blue light exposure, however, LATeNT potently inhibited synaptic transmission in multiple brain regions. The effect could be reversed over 24 hours. We used LATeNT to discover an interneuron population in hippocampus that controls anxiety-like behaviors in mouse, and to control the secretion of endogenous insulin from pancreatic beta cells. Synthetic circuits incorporating LATeNT converted drug, Ca2+, or receptor activation into transgene expression or reporter protein secretion. Due to its large dynamic range, rapid kinetics, and highly specific mechanism of action, LATeNT should be a robust tool for conditional proteolysis and spatiotemporal control of synaptic transmission in vivo.

biochemistry↗

LIN28-mediated gene regulatory loops synchronize developmental transitions throughout organogenesis

Precise control of the intervals between self-renewal, proliferation, and differentiation of stem/progenitor cells are coordinated by developmental regulators, comprised of both microRNAs (miRNAs) and proteins, termed heterochronic genes. These heterochronic factors make up a unique subset of evolutionarily conserved genes that regulate the developmental rate and timing of metazoans from worms to mammals. We and others have shown critical roles for the RNA-binding proteins (RBPs) Lin28 during pluripotency, reprogramming, and organogenesis. There has been much investigation into the negative feedback loop between the Lin28-RBPs and the miRNAs-Let-7 during development and disease. Albeit there are fewer investigations into how positive feedback loops between mammalian Lin28-RBPs and mRNAs order mammalian spatiotemporal transitions of progenitors from specification to organogenesis. Screening for factors that activate luciferase reporters of the human LIN28A and LIN28B promoters, in combination with genetic mouse models, we demonstrate positive feedforward loops between key developmental transcription factors such as B-Catenin, Sox2, Sox9, and Lin28-RBPs. Furthermore, we demonstrate heterochronic regulation of morphogenesis and ultimately differentiation is not only genetically moderated but also molecularly fine-tuned via position-dependent sequences in the 5 and/or 3 untranslated regions.

developmental biology↗

Biofabrication of spatially organized temporo-mandibular fibrocartilage assembloids

The combination of mesenchymal stem cell (MSC) spheroids and polymeric scaffolds has been actively explored for engineering organized hyaline cartilage; however, its application to other types of cartilage remains under-explored. The temporo-mandibular joint (TMJ) fibrocartilage is a highly stratified tissue whose recapitulation remains challenging. In this study, the shape and growth orientation of assembloids were controlled by seeding early mature human adipose-derived MSC spheroids into polymeric scaffolds with a dual architecture of micron-scale fibers. This results in flattened asymmetric tissues with a single-sided articular surface. Structurally, the engineered fibrocartilage mimicked the histotypical organization observed in the native human condylar fibrocartilage, notably featuring a thick fibrous zone with flattened cells. Native-like distribution of general extracellular matrix (ECM) components, including glycosaminoglycans and total collagens, and ECM-specific components, such as type I and II collagens, aggrecan core protein, and fibronectin, were observed. Collagen organization, as demonstrated by polarized light microscopy and scanning electron microscopy at the fibril level, was also found to be similar to that of native human tissue. Zonal-dependent micromechanical properties were identified in both the engineered and native tissues, although lower mechanical properties were observed in the fibrous zone of the engineered tissue. This work provides further evidence that the combination of MSC spheroids and micron-sized fiber polymeric scaffolds is a versatile approach for engineering stratified cartilage and a promising strategy for engineering biomimetic fibrocartilage grafts for TMJ reconstruction.

bioengineering↗

Investigating the potential role of capsaicin in facilitating the spread of coxsackievirus B3 via extracellular vesicles

Coxsackievirus B3 (CVB3) is a non-enveloped picornavirus that can cause systemic inflammatory diseases including myocarditis, pericarditis, pancreatitis, and meningoencephalitis. We have previously reported that following infection, CVB3 localizes to mitochondria, inducing mitochondrial fission and mitophagy, while inhibiting lysosomal degradation by blocking autophagosome-lysosome fusion. This results in the release of virus-laden mitophagosomes from the host cell as infectious extracellular vesicles (EVs) which allow non-lytic viral egress. Transient receptor potential vanilloid 1 (TRPV1/TRPV1) is a heat and capsaicin-sensitive cation channel that regulates mitochondrial dynamics by inducing mitochondrial membrane depolarization and fission. In this study, we found that treating cells with the TRPV1 agonist capsaicin dramatically enhances CVB3 egress via EVs. Analysis of the released EVs revealed increased levels of viral capsid protein VP1/VP1, mitochondrial protein TOM70/TOMM70, and fission protein phospho-DRP1/DNM1L (Ser 616). Moreover, these EVs exhibited increased levels of heat shock protein HSP70/HSPA1A, suggesting a potential role of these chaperones in facilitating infectious EV release from cells. Furthermore, TRPV1 inhibition with capsazepine significantly reduced viral infection in vitro. We previously observed similar effects in vitro with another TRPV1 inhibitor SB-366791. Our current in vivo studies found that SB-366791 significantly mitigates pancreatic damage and reduces viral titers in mouse model of CVB3 pancreatitis. Given the lack of understanding regarding the factors that contribute to diverse clinical manifestations of CVB3, our study highlights capsaicin and TRPV1 as potential exacerbating factors that facilitates CVB3 dissemination via mitophagy-derived EVs. IMPORTANCECVB3 is a prevalent pathogen responsible for a range of severe diseases, including myocarditis, pericarditis, pancreatitis, and meningoencephalitis. Despite its clinical significance, factors that determine the severity of CVB3 infection and why some individuals experience life-threatening manifestations while others have mild, cold-like symptoms remain poorly understood. This study provides new insights into the molecular mechanisms underlying CVB3 dissemination and pathogenesis. By investigating the role of capsaicin, a common dietary component, in modulating viral spread, we demonstrate that activation of TRPV1 by capsaicin enhances release of infectious CVB3 via mitophagy-derived EVs. Our results offer novel evidence that modulating TRPV1 activity could influence the clinical outcomes of CVB3 infection, opening new avenues for therapeutic interventions. Given the widespread consumption of capsaicin, this study highlights an important dietary factor that could play a role in shaping CVB3 pathogenesis and its clinical manifestations, underscoring the potential for targeted strategies to mitigate severe disease outcomes.

microbiology↗

DNA Hanger: Surface Free Single-Molecule Blotting Platform

Immunoblotting typically requires protein immobilization onto a membrane surface for quantification. Particularly, in real-time single-molecule blotting, stringent surface passivation is essential to prevent false-positive signals from nonspecific binding. In this study, we introduce a novel surface-free single-molecule blotting platform, termed the DNA Hanger. This platform employs a 3D structure of a quartz slide. Modified{lambda} -phage DNA molecules are randomly biotinylated along their bases and suspended between 4 m-high thin barriers, positioned away from the quartz slide surface. A light sheet, produced within the 3D structure, illuminates fluorophore-conjugated proteins bound to the biotinylated DNA, enabling single-molecule detection. The DNA Hanger assay significantly reduces nonspecific binding and enhances sensitivity to sub-picomolar concentrations, suggesting that this platform provides a novel, surface-condition-independent, and real-time approach in a wide range of single-molecule blotting.

biophysics↗

PPARγ downregulation in colonic CD8+ T cells results in epithelial barrier disruption in people with HIV on antiretroviral therapy

A hallmark of HIV infection is disruption of intestinal barrier integrity that persists in people with HIV (PWH) despite treatment with antiretroviral therapy (ART). This disruption is central to HIV disease progression, yet the causes remain incompletely understood. We report a novel mechanism by which immunometabolic defects in colon resident CD8+ T cells in PWH lead to intestinal epithelial apoptosis and disruption of intestinal barrier integrity. We show that in PWH, these cells downregulate the lipid sensor peroxisome proliferator-activated receptor-{gamma} (PPAR{gamma}), which results in reduced intracellular lipid droplets, impaired fatty acid oxidation, and acquisition of lipids by CD8+ T cells from intestinal epithelial cells, which then contributes to epithelial cell death. Our findings indicate that HIV-associated immunometabolic dysregulation of colon CD8+ T cell leads to loss of intestinal epithelial homeostasis. These results identify potential new strategies to reduce comorbidities in PWH and other disorders with disrupted intestinal barrier integrity.

immunology↗

Characterization of newly isolated bacteriophages targeting carbapenem-resistant Klebsiella pneumoniae

Klebsiella pneumoniae, a Gram-negative opportunistic pathogen, is increasingly resistant to carbapenems in clinical settings. This growing problem necessitates the development of alternative antibiotics, with phage therapy being one promising option. In this study, we investigated novel phages targeting carbapenem-resistant Klebsiella pneumoniae (CRKP) and evaluated their lytic capacity against clinical isolates of CRKP. First, 23 CRKP clinical isolates were characterized using Multi-locus Sequence Typing (MLST), carbapenemase test, string test, and capsule typing. MLST classified the 23 K. pneumoniae isolates into 10 sequence types (STs), with the capsule types divided into nine known and one unknown type. From sewage samples collected from a tertiary hospital, 38 phages were isolated. Phenotypic and genotypic characterization of these phages was performed using Random Amplification of Polymorphic DNA-PCR (RAPD-PCR), transmission electron microscopy (TEM), and whole genome sequencing (WGS) analysis. Host spectrum analysis revealed that each phage selectively lysed strains sharing the same STs as their hosts, indicating ST-specific activity. These phages were subtyped based on their host spectrum and RAPD-PCR, identifying nine and five groups, respectively. Fourteen phages were selected for further analysis using TEM and WGS, revealing 13 Myoviruses and one Podovirus. Genomic analysis grouped the phages into three clusters: one closely related to Alcyoneusvirus, one to Autographiviridae, and others to Straboviridae. Our results showed that the host spectrum of K. pneumoniae-specific phages corresponds to the STs of the host strain. These 14 novel phages also hold promise as valuable resources for phage therapy against CRKP.

microbiology↗