Biology subjects

Wong, J.

Publications and source records attributed to Wong, J..

At least 55 records · Page 3Linked to original sources

bioRxiv2025

Expression and Characterization of SARS-CoV-2 Spike Protein in Thermothelomyces heterothallica C1

The COVID-19 pandemic demonstrated a pressing need for rapid, adaptive, and scalable manufacturing of vaccines and reagents. With the transition into an endemic disease and rising threats of other emerging pandemics, production of these biologicals requires a stable and sustainable supply chain and accessible distribution methods. In this study, we demonstrate the strength of an engineered filamentous fungal platform, Thermothelomyces heterothallica C1, for high volumetric productivity of the full-length spike glycoprotein. Spike protein produced in this system is highly thermostable and immunization of mice with spike made in C1 or mammalian platforms resulted in a similar humoral response. Additionally, it was shown that the native N-glycan profile can be redecorated with complex sialylated structures, if necessary, resulting in a more human-like glycan profile, without impacting binding characteristics as shown experimentally and in simulations. Through extensive physicochemical analysis, the C1 produced spike performs similarly to spike proteins produced in other commercially available systems. The data presented is evidence that C1 can be a strong platform for production of complex glycosylated recombinant proteins such as subunit antigen vaccines.

bioengineering↗

bioRxiv2025

Validation of bronchial airway gene expression associated with bronchiectasis in nasal epithelium

ObjectivesExamination of bronchial epithelium-derived gene expression signature of bronchiectasis (BE) in nasal epithelium. MethodsWe studied 220 participants from the Detection of Early Lung Cancer Among Military Personnel study with bulk RNA-seq of nasal epithelium brushings. Gene set enrichment analysis (GSEA) was used to examine whether genes previously identified as increased or decreased in the bronchial epithelium of individuals with radiologic BE are significantly enriched among the genes most significantly altered in the nasal epithelium. GSEA and cell-type specific gene expression signatures were used to examine changes in the cellular composition of nasal epithelium associated with radiologic BE. ResultsGenes previously found to have significantly altered expression in bronchial epithelium in radiologic BE are concordantly enriched among the genes most increased or decreased in nasal epithelium in radiologic BE in this validation set (p = 3x10-7, increased; p = 6x10-8, decreased). GSEA performed using cell-type signatures demonstrates that in nasal epithelium, BE is associated with increased multiciliated and deuterosomal cell-related gene expression and decreased expression of basal cell- related gene expression, consistent with our previous findings in bronchial epithelium. ConclusionOur work validates our bronchial signature of BE in an independent dataset and demonstrates that similar gene expression changes are associated with radiologic BE in the bronchial and nasal epithelium. These findings support considering nasal epithelium brushing as a less invasive tool for screening and monitoring BE. SummaryThis study validates a previously reported bronchial signature of bronchiectasis (BE) in nasal epithelium. Changes in gene expression and cell-type composition associated with radiologic BE are similar across both bronchial and nasal epithelium.

bioinformatics↗

bioRxiv2025

Capsule-mediated O-antigen masking protects hypervirulent Klebsiella pneumoniae from neutrophil killing

Klebsiella pneumoniae is listed as a critical priority pathogen by the WHO due to prevalent extended-spectrum {beta}-lactamase and carbapenem resistance and high mortality rates Hypervirulent K. pneumoniae (hvKp) causes life-threatening infections in immunocompetent individuals, while classical K. pneumoniae (cKp) causes nosocomial infections in immunosuppressed patients. The convergence of hypervirulence with antibiotic resistance is now a major global health threat. Using a murine pulmonary infection model, we show that hvKp resisted clearance despite significant neutrophil recruitment. Using clinical hvKp and cKp isolates, bone marrow derived neutrophils, cell biology, pharmacology and imaging (both light and electron microscopy) in ex vivo assays revealed that the hvKp hypermucoviscous capsule prevents bacterial recognition and neutrophil activation, blocking ROS production, degranulation, and neutrophil extracellular traps (NETs) formation. In the absence of capsule ({Delta}wcaJ) or hypermucoid capsule determinants ({Delta}rmpADC), hvKp activates neutrophils, leading to degranulation, NET formation and bacterial killing. While superimposing the absence of O-antigen ({Delta}rfb) on the {Delta}wcaJ abrogates degranulation, neutrophils still elaborate NETs that eliminate the {Delta}wcaJ/{Delta}rfb mutant at high efficiency. This suggests that O-antigen is a double-edged sword, functioning as a PAMP triggering neutrophil degranulation yet assisting the pathogen to evade NET-mediated destruction. These findings shed light on the mechanism underpinning immune evasion by the hypervirulent capsule in hvKp.

microbiology↗

bioRxiv2025

Glucosylceramide induced ectosomes propagate pathogenic α-synuclein in Parkinson's disease

Intercellular transmission of -synuclein contributes to Parkinsons disease pathology. Yet, the mechanisms of -synuclein spread are not fully understood. Here, we used live-cell microscopy to examine the impact of Parkinsons disease associated lipid alterations on -synuclein release. We discovered that increased glucosylceramides induce ectosome shedding from primary neurons, and from dopaminergic neurons derived from Parkinsons disease patient iPSCs harboring mutations in GBA1 (N370S, L444P and W378G) and LRRK2 (G2019S and R1441H) compared to their isogenic control. We show that elevated glucosylceramide similarly increases vesicle release and uptake by other neurons in living mouse brains using 2-photon microscopy. Finally, we show that ectosomes are loaded with pathogenic -synuclein and lead to the transmission of -synuclein pathology to neighbouring neurons. These data reveal ectosomes as the predominant route for -synuclein transmission that can only be appreciated by live-cell imaging technologies.

cell biology↗

bioRxiv2025

Experimental conditions to retrieve intrinsic cooperativity α directly from single binding assay data exemplified by the ternary complex formation of FKBP12, MAPRE1 and macrocyclic molecular glues

The incorporation of disease-relevant targets in a compound-dependent manner into ternary complexes with an assisting chaperone protein has become a common modality. Among the various types of ternary complex-forming compounds, molecular glues are of particular interest because they do not require significant binary (independent) target affinity. Instead, ternary complexes formed by molecular glues retrieve a significant part of their thermodynamic stability through newly induced chaperone-target or glue-target interactions that occur only in the ternary complex. These interactions lead to enhanced ligand binding - termed intrinsic cooperativity - which can be retrieved via the apparent cooperativity either by monitoring ligand binding through the chaperone or through the target protein. In this publication, the advantage of measuring the apparent cooperativity to determine the cooperativity by the weaker binding protein is discussed and illustrated using the example of ternary complexes between FKBP12, MAPRE1 and macrocyclic molecular glues derived from the rapamycin binding motif for FKBP12. Furthermore, the impact of the following three parameters on the apparent cooperativity is illustrated: 1.) the concentration of the monitoring protein, 2.) the excess of the counter protein, 3.) the affinity of the glue to the weaker binding protein in combination with the degree of intrinsic cooperativity . From this, experimental conditions to determine the intrinsic cooperativity with only one binding assay and without the need for a comprehensive mathematical model covering all simultaneous events under non-saturating conditions are highlighted. However, this framework requires a binding assay capable of measuring or at least estimating very weak binary affinities. If this is not possible for experimental reasons, but binding assays for both proteins are available within a normal bandwidth and the affinity to the stronger binding protein is not too high, it is discussed how the binding curve for the weaker binding protein in the presence of an excess of the weaker binding protein can be used to overcome the missing binary Kd for the weakly binding protein.

biochemistry↗

bioRxiv2024

Thyroid hormones act as a timer for the postnatal maturation of parvalbumin neurons in mouse neocortex

Thyroid hormones (THs) are required for proper maturation of parvalbumin-expressing GABAergic interneurons in the mouse neocortex, which function is essential to maintain a proper balance between neuronal excitation and inhibition. However, the timeline of this TH action has yet to be elucidated. Here, we used several mouse models expressing dominant negative mutations of the TH nuclear receptor 1 (TR1), to better define the time window during which THs promote the maturation of parvalbumin neurons. The action of THs during the first three postnatal weeks appears to be necessary to initiate the elaboration of a specialized extracellular matrix called the perineuronal net. Transcriptome analysis identified a small set of putative target genes for TR1, which are at the origin of the postnatal remodeling of the repertoire of ions channels and the elaboration of perineuronal nets. These data suggest that THs act as a timer to define the temporal boundaries of the critical period of heightened cortical plasticity, which plays a fundamental role in the development of neuronal circuits. Significance statementThyroid hormones exert a major influence on late neurodevelopment, acting directly on gene expression by binding to nuclear receptors present in all cell types. This study reports the discovery of a direct link between the transcriptional regulation exerted by the thyroid hormones in GABAergic neurons and the timing of the critical period of heightened plasticity. This provides a general framework to understand the pathology associated with altered thyroid hormone signaling.

developmental biology↗

bioRxiv2024

Control of spatiotemporal activation of organ-specific fibers in the vagus nerve by intermittent interferential current stimulation

Vagus nerve stimulation (VNS) is emerging as potential treatment for several chronic diseases, however, limited control of fiber activation to promote desired effects over side effects restricts clinical translation. Here we describe a new VNS method that relies on intermittent, interferential sinusoidal current stimulation (i2CS) through implanted, multi-contact epineural cuffs. In swine, i2CS elicits specific nerve potentials and end organ responses, distinct from equivalent non-interferential sinusoidal stimulation. Comparing experimental results with anatomical trajectories of nerve fascicles from end organs to the stimulation electrode indicates that i2CS activates organ-specific fascicles rather than the entire nerve. Experimental results and anatomically realistic, physiologically validated biophysical models of the vagus nerve demonstrate that i2CS reduces fiber activation at the focus of interference. Current steering and repetition frequency determine spatiotemporal pattern of vagal fiber activation, allowing tunable and precise control of neural and organ responses. In experiments in a cohort of anesthetized swine, i2CS has improved selectivity for a desired effect, mediated by smaller bronchopulmonary fibers, over a side effect, mediated by larger laryngeal fibers, compared to non-interferential sinusoidal or square pulse VNS.

neuroscience↗

bioRxiv2024

Polymorphisms in rs2069845 are associated with IL-6 and soluble IL-6 receptor levels during total joint replacement

As the number of patients undergoing total joint replacement (TJR) surgery increases, so does the number of revision surgeries. One driver of implant failure and subsequent revision surgery is peri-implant osteolysis, which is driven by inflammation-mediated bone loss. IL-6 is an inflammatory marker that is elevated during the peri-operative period. Early elevations in IL-6 levels have been linked to osteolysis development. The current study asked whether there is genetic contribution to the IL-6-related peri-operative inflammatory reaction to TJR surgery. Patients undergoing primary TJR (total hip or total knee) provided pre-operative and post-operative blood samples for measurement of the circulating levels of IL-6 and the soluble IL-6 receptor (sIL-6r) and evaluation of allele status of three single nucleotide polymorphisms (SNPs) linked to IL-6 or sIL-6r levels - rs2069845, rs228145, and rs4537545. Circulating sIL-6r levels were associated with allele status in the rs2228145 SNP. More interestingly, allele status in the rs2069845 SNP was associated with the change in circulating IL-6 levels following TJR surgery. Specifically, patients with the A,A allele had increasing levels of IL-6, while those harboring the G,A allele had decreasing levels of IL-6. Although the study was not designed to follow implant survival, due to the critical role of IL-6 in driving peri-implant osteolysis development, the results may suggest that the rs2069845 allele has a role in the success of orthopedic implants. rs2069845 polymorphisms may be a useful patient-specific marker of inflammatory response to TJR surgery.

genetics↗

bioRxiv2024

Discovery of broad-spectrum bacterial polyamine detoxification inhibitors as potential antivirulence agents and antibiotic adjuvants

The alarming rise in antimicrobial resistance reinforces an urgent need for new antimicrobial strategies. Host- or bacteria-derived chemicals, such as polyamines, present at infection sites often influence microbial virulence and antibiotic response. Polyamines are cationic small molecules overproduced by the host during infection, modulating immune responses. Polyamine detoxification by several pathogens correlates with increased virulence. We sought to uncover inhibitors of polyamine detoxification through a high-throughput whole-cell screen against the community-acquired methicillin-resistant Staphylococcus aureus (MRSA) USA300, identifying the polyamine analog OES2-0017 and the catechol derivative isoproterenol (OES1-1087), which synergized with polyamines in the low-micromolar range. Chemical genomics and enzymatic assays combined with computational studies revealed that both compounds prevented polyamine detoxification by spermine/spermidine acetyltransferase SSAT (SpeG) and another previously uncharacterized S. aureus SSAT (denoted PaiASa herein). OES2-0017 directly inhibited the enzymes, whereas OES1-1087 reduced intracellular levels of acetyl-CoA required for SSAT activity. OES2-0017 perturbed the bacterial membrane at higher concentrations, likely causing the observed growth-inhibitory effects, whereas OES1-1087 increased membrane fluidity, likely increasing susceptibility to spermine-mediated membrane perturbation. The inhibitors showed broad-spectrum activity against various Gram-positive and Gram-negative bacteria, as well as Candida albicans. OES2-0017 abolished the spermine-mediated protection of MRSA USA300 from antibiotics, including vancomycin, phenocopying the {Delta}speG mutant and suggesting its potential utility as an antibiotic adjuvant. OES2-0017 eradicated SpeG-expressing Salmonella Typhimurium inside murine macrophages, whereas OES1-1087 reduced the S. Typhimurium burden in the liver and spleen in a murine gastrointestinal infection model, demonstrating their potential as antivirulence agents. Neither inhibitor exhibited cytotoxic activity against eukaryotic cells at their respective antimicrobial ranges. Small-scale structure-activity relationship experimental and computational analyses identified OES2-0017 analogs with improved specificity for the bacterial enzyme compared to the human SAT1 and no toxicity. This study provides novel antimicrobial compounds with broad-spectrum activity and a novel mode of action for multidrug-resistant priority pathogens.

microbiology↗

bioRxiv2024

Odorant receptors tuned to isothiocyanates in Drosophila melanogaster and their evolutionary expansion in herbivorous relatives

Plants release defense volatile compounds that can deter herbivores. Among them are electrophilic toxins, such as isothiocyanates from mustard plants, that activate pain receptors by contact (i.e. taste) in many animals, including Drosophila melanogaster. While specialist insects have evolved strategies to tolerate toxicity and use mustard plants as hosts, it is unclear whether non-specialist insects detect and avoid electrophilic toxins via olfaction. To address this, and to understand if specialized insects co-opted these toxic compounds as hostplant olfactory cues, we leveraged closely related drosophilid species, including the microbe-feeding D. melanogaster and Scaptomyza pallida, and the mustard-feeding specialist S. flava. In olfactory assays, D. melanogaster exposed to allyl isothiocyanate volatiles were rapidly immobilized, demonstrating the high toxicity of this wasabi-derived compound to non-specialists. Through single sensillum electrophysiological recordings from olfactory organs and behavioral assays, we identified an Olfactory receptor (Or) necessary for volatile detection and behavioral aversion to allyl isothiocyanate in D. melanogaster. RNA sequencing and heterologous expression revealed that S. flava possess lineage-specific, triplicated homologs of this Or, and that each paralog exhibited broadened and distinct sensitivity to isothiocyanate compounds. Using AlphaFold2 modeling, site-directed mutagenesis and electrophysiological recordings, we identified two critical amino acid substitutions that changed the sensitivity of these paralogs from fruit-derived odors to isothiocyanates in the mustard specialist S. flava. Our findings show that non-specialists can detect electrophiles via olfaction, and that their olfactory systems can rapidly adapt to toxic hostplant niches through co-option and duplication of ancestral chemosensory genes with few amino acid changes.

evolutionary biology↗

bioRxiv2024

GoldPolish-Target: Targeted long-read genome assembly polishing

BackgroundAdvanced long-read sequencing technologies, such as those from Oxford Nanopore Technologies and Pacific Biosciences, are finding a wide use in de novo genome sequencing projects. However, long reads typically have higher error rates relative to short reads. If left unaddressed, subsequent genome assemblies may exhibit high base error rates that compromise the reliability of downstream analysis. Several specialized error correction tools for genome assemblies have since emerged, employing a range of algorithms and strategies to improve base quality. However, despite these efforts, many genome assembly workflows still produce regions with elevated error rates, such as gaps filled with unpolished or ambiguous bases. To address this, we introduce GoldPolish-Target, a modular targeted sequence polishing pipeline. Coupled with GoldPolish, a linear-time genome assembly algorithm, GoldPolish-Target isolates and polishes user-specified assembly loci, offering a resource-efficient means for polishing targeted regions of draft genomes. ResultsExperiments using Drosophila melanogaster and Homo sapiens datasets demonstrate that GoldPolish-Target can reduce insertion/deletion (indel) and mismatch errors by up to 49.2% and 53.4% respectively, achieving base accuracy values upwards of 99.9% (Phred score Q>30). This polishing accuracy is comparable to the current state-of-the-art, Medaka, while exhibiting up to 36-fold shorter run times and consuming 94% less memory, on average. ConclusionGoldPolish-Target, in contrast to most other polishing tools, offers the ability to target specific regions of a genome assembly for polishing, providing a computationally light-weight and highly scalable solution for base error correction. Availabilityhttps://github.com/bcgsc/goldpolish

genomics↗

bioRxiv2024

The exopolysaccharide Poly-N-Acetyl-Glucosamine (PNAG) coats Klebsiella pneumoniae in vivo

The conserved bacterial polysaccharide Poly-N-Acetyl-Glucosamine (PNAG) is a potential broad-spectrum vaccine candidate. While the immunogenicity of PNAG-based vaccine candidates has been established, characterisation of PNAG production across clinically relevant bacteria remains largely unknown. In particular, PNAG production in the Gram-negative pathogen Klebsiella pneumoniae (KP) is not well understood. Here, we demonstrate that PNAG production is prevalent in clinical KP isolates, where it is secreted as extracellular networks during adherent growth conditions. However, during severe KP pulmonary infection, KP PNAG production undergoes a switch to a cell-associated phenotype, coating the bacterial cell surface. By screening a panel of isogenic KP mutants in prominent cell surface components ({Delta}wcaJ,{Delta} rmpADC,{Delta} rfb,{Delta} ompA and{Delta} ompk36), we identified KP capsular polysaccharide as a key determinant underpinning the phenotype. Deleting genes involved in capsule synthesis ({Delta}wcaJ) and regulation ({Delta}rmpADC) resulted in cell-associated PNAG during adherent growth and infection of alveolar epithelial cells in vitro. Taken together, we describe a novel interaction between KP surface polysaccharides and detect for the first time, cell-associated PNAG in KP during lung infection, highlighting PNAG as an attractive KP vaccine antigen. Author summaryThe Gram-negative pathogen Klebsiella pneumoniae (KP) is a leading cause of hospital-associated lung and bloodstream infections worldwide. As KP exhibits resistance to most frontline antibiotics, there is a growing demand for immune-based strategies to treat KP infections. Poly-N-Acetyl-Glucosamine (PNAG) is a surface sugar produced by most clinically relevant bacteria, including KP. However, relatively little is known about PNAG production in KP. Therefore, we set out to characterise PNAG production in KP during in vitro growth and following lung infection in a pulmonary mouse model. During in vitro growth, KP produces extracellular PNAG networks. In contrast, during an in vivo severe lung infection, PNAG is found cell-associated, coating the bacterial surface. We propose that the visible change in KP PNAG between in vitro and in vivo environments is due to crosstalk with capsule, another polysaccharide on the KP surface. Together, this supports PNAG as an attractive KP antigen.

microbiology↗

bioRxiv2024

Synergistic DNA and RNA binding of the Hox transcription factor Ultrabithorax coordinates splicing and shapes in vivo homeotic functions

The dual interaction of many transcription factors (TFs) with both DNA and RNA is an underexplored issue that could fundamentally reshape our understanding of gene regulation. We address this central issue by investigating the RNA binding activity of the Drosophila Hox TF Ultrabithorax (Ubx) in alternative splicing and morphogenesis. Relying on molecular and genetic interactions, we uncover a homodimerization-dependent mechanism by which Ubx regulates splicing. Notably, this mechanism enables the decoupling of Ubx-DNA and -RNA binding activity in splicing. We identify a critical residue for Ubx-RNA binding and demonstrate the essential role of Ubx-RNA binding ability for its homeotic functions. Overall, we uncover a unique mechanism for Ubx-mediated splicing and underscore the critical contribution of synergistic DNA/RNA binding for its morphogenetic functions. These findings advance our understanding of co-transcriptional regulation and highlight the significance of TF-DNA/RNA synergistic function in shaping gene regulatory networks in living organisms. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/612310v1_ufig1.gif" ALT="Figure 1"> View larger version (65K): org.highwire.dtl.DTLVardef@6b3f84org.highwire.dtl.DTLVardef@116f353org.highwire.dtl.DTLVardef@1c0ceb4org.highwire.dtl.DTLVardef@142906c_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIUbx homodimerization enables decoupling of DNA- and RNA-dependent splicing regulation C_LIO_LIThe homeodomain K58 amino acid is critical for Ubx-RNA binding ability C_LIO_LIUbx-RNA binding ability is essential for splicing regulation C_LIO_LIDual DNA/RNA binding activities shape Ubx homeotic functions C_LI

molecular biology↗

bioRxiv2024

Selective regulation of IFN-γ and IL-4 co-producing unconventional T cells by purinergic signalling

Unconventional T cells, including mucosal-associated invariant T (MAIT), natural killer T (NKT), and gamma-delta T ({gamma}{delta}T) cells, comprise distinct T-bet+, IFN-{gamma}+ and ROR{gamma}t+, IL-17+ subsets which play differential roles in health and disease. NKT1 cells are susceptible to ARTC2-mediated P2X7 receptor (P2RX7) activation, but the effects on other unconventional T-cell types are unknown. Here, we show that MAIT, {gamma}{delta}T, and NKT cells express P2RX7 and are sensitive to P2RX7-mediated cell death. Mouse peripheral T-bet+ MAIT1, {gamma}{delta}T1, and NKT1 cells, especially in liver, co-express ARTC2 and P2RX7, which can be further upregulated by retinoic acid. Blocking ARTC2 or inhibiting P2RX7 protected MAIT1, {gamma}{delta}T1, and NKT1 cells from cell death, enhanced their survival in vivo, and increased the number of IFN-{gamma}-secreting cells without affecting IL-17 production. Importantly, this revealed the existence of IFN-{gamma} and IL-4 co-producing unconventional T-cell populations normally lost upon isolation due to ARTC2/P2RX7-induced death. Administering extracellular NAD in vivo activated this pathway, depleting P2RX7-sensitive unconventional T cells. Our study reveals ARTC2/P2RX7 as a common regulatory axis modulating the unconventional T-cell compartment, affecting the viability of IFN-{gamma}- and IL-4-producing T cells, offering important insights to facilitate future studies into how these cells can be regulated in health and disease.

immunology↗

bioRxiv2024

Addressing Underestimation of Waterborne Disease Risks Due to Fecal Indicator Bacteria Bound in Aggregates

Microbiological water quality monitoring is critical for managing waterborne disease risk; currently, regulations rely on quantifying culturable fecal indicator bacteria using traditional culture-based methods. These approaches cannot distinguish between planktonic forms and aggregates harboring higher loads of bacteria and associated pathogens, potentially underestimating exposure risks. By using size fractionation and ALERT, an automated rapid method for comprehensive quantification of culturable bacteria, we reveal widespread and substantial presence of aggregate-bound indicator bacteria across a variety of water matrices and geographies. We observe comprehensive bacteria counts exceeding traditional method counts by significant multiples (e.g., 3.4x on average at the Seine River 2024 Olympic venue, occasionally 100x in irrigation canals and wastewater plant effluent). The results, corroborated by microscopic and molecular analyses, highlight a major systematic bias in global water safety regulatory frameworks. Automated comprehensive culture-based rapid quantification methods could provide higher-accuracy risk assessments, enabling effective monitoring, including in remote and resource-limited settings.

microbiology↗

bioRxiv2024

Thyroid hormones maintain parvalbumin neuron functions in mouse neocortex

Parvalbumin-expressing GABAergic interneurons play a key role in maintaining the excitation-inhibition balance in the mammalian neocortex. While postnatal maturation of parvalbumin neurons is highly sensitive to thyroid hormone deficiency, the role of these hormones in mature parvalbumin neurons remains poorly understood. Here, we addressed the possibility that thyroid hormones are also required to maintain the function of mature parvalbumin neurons in the mouse neocortex. To this end, Cre/loxP recombination system was used to express a dominant-negative mutated receptor of thyroid hormones to selectively eliminate thyroid hormone signaling in parvalbumin neurons after the onset of parvalbumin expression. We analyzed the neocortical phenotype of these mice by combining genomics, histology, electrophysiology, sleep recordings and behavioral analysis. In the mutant mice, gene expression analysis revealed a decreased expression of key perineuronal net components. parvalbumin neuron excitability was decreased and mice displayed behavioral hyperactivity and increased susceptibility to epileptic seizures. Additionally, sleep analysis revealed that mutant mice spent more time awake, and had a delayed transition to sleep. Electrophysiological recordings further demonstrated altered gamma oscillations in the somatosensory cortex. The findings of this study underscore that thyroid hormones are essential not only for the differentiation of parvalbumin interneurons, but also for the maintenance of their inhibitory function after the onset of parvalbumin expression. As a consequence, alterations in thyroid hormone signaling, during development or in adulthood, may contribute to the occurrence of neurological and psychiatric disorders involving altered cortical oscillations.

neuroscience↗

bioRxiv2024

Disruption of Immune Responses By Type I Diabetes Exacerbates SARS-CoV-2 Mediated Lung Injury

COVID-19 commonly presents as pneumonia, with those most severely affected progressing to respiratory failure. Patient responses to SARS-CoV-2 infection are varied, with comorbidities acting as major contributors to varied outcomes. Focusing on one such major comorbidity, we assessed whether pharmacological induction of Type I Diabetes Mellitus (T1DM) would increase the severity of lung injury in a murine model of COVID-19 pneumonia utilizing wild type mice infected with mouse-adapted SARS-CoV-2. Hyperglycemic mice exhibited increased weight loss and reduced blood oxygen saturation in comparison to their euglycemic counterparts, suggesting that these animals indeed experienced more severe lung injury. Transcriptomic analysis revealed a significant impairment of the adaptive immune response in the lungs of diabetic mice compared to those of control. In order to expand the limited options available for tissue analysis due to biosafety restrictions, we also employed a novel technique to digest highly fixed tissue into a single cell suspension, which allowed for flow cytometric analysis as well as single cell RNA sequencing. Flow immunophenotyping and scRNA-Seq confirmed impaired recruitment of T cells into the lungs of T1DM animals. Additionally, scRNA-Seq revealed a distinct, highly inflammatory macrophage profile in the diabetic cohort that correlates with the more severe infection these mice experienced clinically, allowing insight into a possible mechanism for this phenomenon. Recognizing the near certainty that respiratory viruses will continue to present significant public health concerns for the foreseeable future, our study provides key insights into how T1DM results in a much more severe infection and identifies possible targets to ameliorate comorbidity-associated severe disease. NEW AND NOTEWORTHYWe define the exacerbating effects of Type I Diabetes Mellitus (T1DM) on COVID-19 pneumonia severity in mice. Hyperglycemic mice experienced increased weight loss and reduced oxygen saturation. Transcriptomic analysis revealed impaired immune responses in diabetic mice, while flow cytometry and single-cell RNA sequencing confirmed reduced T cell recruitment and an inflammatory macrophage profile. Additionally, we introduced a novel technique for tissue analysis, enabling flow cytometric analysis and single-cell RNA sequencing on highly fixed tissue samples.

immunology↗

bioRxiv2024

Caspase-11 drives macrophage hyperinflammation in models of Polg-related mitochondrial disease

Mitochondrial diseases (MtD) represent a significant public health challenge due to their heterogenous clinical presentation, often severe and progressive symptoms, and lack of effective therapies. Environmental exposures, such bacterial and viral infection, can further compromise mitochondrial function and exacerbate the progression of MtD. Infections in MtD patients more frequently progress to sepsis, pneumonia, and other detrimental inflammatory endpoints. However, the underlying immune alterations that enhance immunopathology in MtD remain unclear, constituting a key gap in knowledge that complicates treatment and increases mortality in this vulnerable population. Here we employ in vitro and in vivo approaches to clarify the molecular and cellular basis for innate immune hyperactivity in models of polymerase gamma (Polg)-related MtD. We reveal that type I interferon (IFN-I)-mediated upregulation of caspase-11 and guanylate-binding proteins (GBPs) increase macrophage sensing of the opportunistic microbe Pseudomonas aeruginosa (PA) in Polg mutant mice. Furthermore, we show that excessive cytokine secretion and activation of pyroptotic cell death pathways contribute to lung inflammation and morbidity after infection with PA. Our work sheds new light on innate immune dysregulation in MtD and reveals potential targets for limiting infection- and inflammation-related complications in Polg-related MtD.

immunology↗