Biology subjects

Saeed, M.

Publications and source records attributed to Saeed, M..

At least 19 recordsLinked to original sources

bioRxiv2026

Male and female mice achieve equivalent protection against heterologous SARS-CoV-2 infection through divergent immune mechanisms

Biological sex is a major determinant of antiviral immunity, yet how it shapes lung-resident antiviral immunity remains poorly understood. We report that prior mild SARS-CoV-2 BA.1 infection protects mice from lethal heterologous Delta challenge through distinct sex-biased immune mechanisms. Although heterologous protection is clinically equivalent between sexes, T- and B-cell depletions before BA.1 exposure abrogate protection only in males. Depletion with anti-CD4, but not anti-CD8, abolishes protection in both sexes, but co-depletion with anti-CD4/anti-CD8 partially restores protection in females only. Further, females exhibit enhanced IFN-gamma-associated myeloid inflammation upon secondary Delta infection. Using lymphoid-deficient mice that display female-biased resistance to Delta infection, IFN-gamma treatment provides partial protection to naive males against Delta. Female resistance is lost after previous BA.1 exposure, highlighting the importance of lymphoid-mediated inflammatory regulation. Together, equivalent antiviral protection against heterologous respiratory viral infection is governed by sexually dimorphic mechanisms, with significant implications for designing mucosal vaccines and immunotherapies.

immunology↗

bioRxiv2026

eIF4E3 drives translation of viral mRNAs with short 5' UTRs

Eukaryotic cells express three paralogs of the cap-binding protein eIF4E, yet the functions of the less-studied family members remain poorly understood. Here we demonstrate that eIF4E3, a paralog whose expression is tissue-restricted and whose activity is insensitive to inhibition by eIF4E-binding proteins (4EBPs), drives efficient translation of viral mRNAs with short 5 untranslated regions (UTRs). Many negative-strand RNA viruses (NSVs), including vesicular stomatitis virus (VSV), respiratory syncytial virus (RSV), and influenza A virus (IAV), produce mRNAs with extremely short 5UTRs that are incompatible with canonical cap-dependent scanning translation initiation. Using an auxin-inducible degron (AID) system to acutely deplete endogenous eukaryotic initiation factors during active viral infection, we demonstrate that translation of these short-UTR viral mRNAs occurs independently of eIF4E1, the canonical cap-binding protein, while remaining dependent on eIF4E3. In contrast, Ebola virus (EBOV), whose mRNAs bear long, structured 5UTRs, remains eIF4E1-dependent, implicating 5UTR length and structural complexity as cis determinants of eIF4E paralog selectivity. During VSV infection, 4EBP dephosphorylation sequesters eIF4E1 and broadly suppresses host cap-dependent translation. Because eIF4E3 escapes 4EBP-mediated regulation and preferentially engages short, unstructured 5UTRs, it is uniquely positioned to sustain viral protein synthesis under these conditions. These findings reveal that VSV exploits a cellular paralog-switching mechanism by co-opting eIF4E3 to maintain viral translation when canonical eIF4F activity is suppressed and establish eIF4E3 as a proviral factor whose tissue-restricted expression in the lung may influence susceptibility to clinically important respiratory pathogens.

molecular biology↗

bioRxiv2026

The enteroviral protease target LSM14A operates outside of P-bodies to augment antiviral innate immunity

Antiviral innate immune networks in human cells comprise core components that serve as central signaling hubs and several context-dependent modulators whose role may be virus- or tissue-specific. One such modulator is LSM14A, which potentiates innate immune response but is not essential. We recently showed that enteroviruses deploy their protease activity to cleave LSM14A, thereby disabling its antiviral function. In this study, we probe the molecular mechanism by which LSM14A contributes to innate immunity. We show that although LSM14A predominantly localizes to processing bodies (P-bodies; PBs), this localization is not essential for its innate immune function. Likewise, association with peroxisomes does not contribute to its immune activity. Instead, an unbiased systems-level interactomic analysis reveals a distinct cohort of LSM14A-associated proteins that assemble outside canonical PBs and peroxisomes following infection with Sendai virus, a robust inducer of innate immunity. Functional interrogation of these interactors demonstrate that several are essential for LSM14A-dependent amplification of antiviral signaling. Together, these findings uncover a functional axis of LSM14A that operates independently of its canonical subcellular localizations and is mediated through a specialized interaction network, improving our understanding of how this protein reinforces the antiviral innate immune system.

microbiology↗

bioRxiv2026

Proteolytic dissection of eIF4G reveals the closed-loop mRNP as an architecture for translation repression.

Formation of a "closed-loop" mRNP, in which the 5' cap and 3' poly(A) tail are bridged by eIF4E-eIF4G-PABP interactions, has long been proposed to drive efficient translation initiation. Direct tests of this model in mammalian cells have remained elusive. Using auxin-inducible degron (AID) technology to acutely deplete eIF4G1, we find that global translation is only partially reduced and recovers without restoration of eIF4G1 levels. We identify eIF4G3 as an underappreciated contributor to basal translation that buffers translational output upon eIF4G1 loss without increased protein expression, explaining the modest defects observed in prior RNAi-based studies. Systematic replacement of eIF4G1 with defined cleavage products and interaction mutants reveals that PABP binding by eIF4G1 is dispensable for bulk translation initiation: the central caspase-3 cleavage fragment of eIF4G1 (casp3-cpM), which lacks the PABP-interaction domain, fully rescues global protein synthesis, and acute depletion of both major cytoplasmic PABP paralogs primarily destabilizes mRNAs rather than impairing initiation. In contrast, the N-terminal enteroviral 2A cleavage product (2A-cpN) is a potent, dominant translational repressor that requires simultaneous eIF4E and PABP engagement to form a dead-end closed-loop mRNP that sequesters initiation factors without enabling 43S recruitment. These findings reveal that the eIF4G-PABP closed-loop architecture is not required for productive initiation but can be actively co-opted for translational silencing. This explains why viral eIF4G cleavage, but not factor depletion, produces near-complete translational shutoff. The modular architecture of eIF4G enables diametrically opposing translational outcomes through selective proteolytic processing.

molecular biology↗

bioRxiv2026

Integrating GlycoSHIELD Modeling and DNA-PAINT SMLM to Map the Glycosylation-Dependent Distri-bution of the Na,K-ATPase

The cell surface localization of the Na,K-ATPase (sodium pump) is required for maintaining transmembrane electrochemical gradients. While glycosylation of the {beta}1 subunit facilitates trafficking from the endoplasmic reticulum to the plasma membrane, its role in nanoscale surface organization is not characterized. This study employed GlycoSHIELD computational modeling and DNA-PAINT single-molecule localization microscopy (SMLM) to evaluate how N-glycans influence pump distribution. In-silico simulations indicated that N-glycans sequester the protein core, providing a steric shield that increases with structural complexity. To investigate this experimentally, glycosylation-deficient mutants (3NQ) were generated and confirmed via immunoblotting. Quantitative SMLM analysis of A498 cells demonstrated that wild-type pumps exhibit higher localization density and form larger (144 nm) and more frequent clusters than 3NQ mutants (109 nm). These results indicate that N-glycosylation promotes stable enzyme clustering, supporting a galectin-lattice mechanism of organization rather than steric repulsion.

cell biology↗

bioRxiv2026

CNOT6 deadenylase safeguards postnatal growth and metabolic transition via Fgf21 mRNA decay

Postnatal growth and development require precise coordination of growth and metabolism to meet the biosynthetic and energetic demands of rapidly expanding organs. Fibroblast growth factor 21 (FGF21) serves as a key endocrine regulator linking nutrient availability to systemic growth control in early life and metabolic homeostasis in adulthood. Here, we identify the CCR4-NOT deadenylase complex subunit CNOT6, but not its paralog CNOT6L, as an essential post-transcriptional regulator of neonatal growth and metabolism. Loss of Cnot6 results in severe growth retardation, multi-organ hypoplasia, and increased perinatal mortality. Surviving Cnot6 knockout mice display markedly reduced body and organ size that gradually normalizes by adulthood, indicating developmental compensation. Mechanistically, Cnot6 deficiency elevates hepatic Fgf21 mRNA expression, suppresses the IGF1-IGFBP1 axis, and reprograms liver transcriptional networks controlling lipid and glucose metabolism and apoptosis. These changes are accompanied by increased ketone body production, suggesting enhanced fatty acid oxidation. Together, our findings uncover a previously unrecognized role of CNOT6 in limiting FGF21 expression to preserve anabolic metabolism during the neonatal period. This work establishes the CNOT6-FGF21 axis as a molecular checkpoint that couples mRNA decay with hormonal and metabolic coordination required for healthy postnatal growth.

molecular biology↗

bioRxiv2025

Domain-specific decoupling of co-chaperone and ligase functions in STUB1 underlies biochemical and clinical heterogeneity in SCA48

AO_SCPLOWBSTRACTC_SCPLOWThe carboxyl terminus of HSC70-interacting protein (CHIP, encoded by STUB1) integrates co-chaperone and E3 ubiquitin ligase activities to maintain proteostasis. Heterozygous STUB1 mutations cause the dominant cerebellar ataxia SCA48 through incompletely understood mechanisms. We characterized 13 SCA48-associated variants in the TPR and U-box domains using recombinant protein and cellular assays. TPR mutations retained intrinsic ligase activity but lost HSC70 binding, substrate ubiquitination efficiency, and protein stability. Conversely, U-box mutations abolished ligase function, induced aberrant high-molecular-weight oligomerization, and frequently elevated steady-state CHIP levels while only partially impairing co-chaperone activity. Many variants exhibited temperature-sensitive defects and stress-induced nuclear mislocalization. Principal component analysis revealed robust domain-specific biochemical clustering. RNA-seq following STUB1 knockdown demonstrated preserved HSF1-dependent transactivation but a loss of CHIP-dependent amplification of ubiquitination, chaperone, and transcriptional pathways under heat stress. Meta-analysis of 87 SCA48 patients linked TPR-like biochemical profiles to upper motor neuron involvement and U-box profiles to prominent dysarthria. Collectively, SCA48 mutations decouple CHIPs dual functions in a domain-dependent manner, exerting dominant-negative or gain-of-toxic effects that drive the observed clinical heterogeneity. These findings establish a direct biochemical-clinical correlation in SCA48 and provide a framework for domain-targeted therapeutic strategies exploiting residual ligase or chaperone activity.

neuroscience↗

bioRxiv2025

Oncogenic RAS activity is linked to immune priming and adenosine-driven immune evasion in lung adenocarcinoma

Lung adenocarcinoma (LUAD) is a leading cause of cancer death worldwide, with RAS signalling as a key oncogenic driver. Although KRAS mutations have been linked to immune evasion in preclinical models, the relationship between RAS activity and tumour immunity or response to immunotherapy in patients remains unclear. Here, we applied our previously validated RAS84 transcriptional signature to stratify LUAD patient cohorts and dissect the immune landscape associated with RAS signalling. We report that tumours with elevated RAS activity exhibited features of immune priming, including increased immune infiltration, interferon response, and immune checkpoint gene expression, and showed improved progression-free survival in an independent cohort of patients treated with anti-PD-1. Yet, in both LUAD tumours and cell lines, RAS activity also correlated with elevated immunosuppressive interstitial adenosine mediated by transcriptional regulation of several components of the adenosinergic pathway. In orthotopic pre-clinical models of high-RAS activity lung tumours, blocking adenosine signalling delayed tumour growth and improved response to anti-PD-1 and KRAS inhibition, with a significant effect on innate immunity. This study reveals a dual role for RAS signalling in tumour progression, fostering a pro-immunogenic environment whilst simultaneously dampening anti-tumoural immunity via mechanisms including extracellular adenosine accumulation. Stratifying patients based on RAS transcriptional activity, rather than genetic alterations alone, could inform immunotherapy strategies and improve clinical outcomes.

cancer biology↗

bioRxiv2025

Development and validation of an ultra-low-cost, open source normothermic ex vivo organ perfusion platform

BackgroundNormothermic ex vivo organ perfusion (NEVOP) promises to catalyze organ preservation, therapeutic discovery, and organ-specific disease modeling. Existing technology platforms remain inaccessible for research due to restricted access to commercial organ perfusion devices, high costs of both devices and proprietary consumables, and steep technical learning curves. Additionally, the available technology is not optimized to perfuse smaller organs such as the kidney. MethodsTo overcome these barriers, a custom NEVOP circuit was developed using recycled, repurposed, and low-cost components. Porcine kidneys and autologous blood were used to iteratively optimize circuit design. A porcine kidney autotransplantation protocol was adapted to evaluate in vivo kidney function after ex vivo perfusion. To pilot the flexibility of this system as a multi-organ platform for ex vivo human biology, non-transplantable human donor kidney, spleen, and pancreas specimens were stably perfused using human blood products and analyzed. ResultsAn ultra low-cost NEVOP system engineered to perfuse porcine kidneys and diverse human organs (kidney, pancreas, and spleen) sustained viable organs for up to 24 hours with evidence of both function and viability. Key innovations included a parallel flow resistor to facilitate low-flow perfusion in non-heparinized organs and a containment bag with adjustable magnets to provide vascular stability and recycling of venous overflow. The circuit costs less than 1,500USD to construct, and porcine kidneys perfused for 24 hours on this platform demonstrated healthy in vivo function upon autotransplantation. ConclusionsCustom NEVOP platforms constitute novel and potentially transformative research platforms which use low-cost and readily available materials. Paired with access to non-transplantable research organs from altruistic donors, this model provides a road map for investigators to advance biomedical discovery and human ex vivo biology.

bioengineering↗

bioRxiv2025

A matrix-mimicking bioadhesive epicardium for tunable modulation of biomechanics in the acutely infarcted heart

Mitigating adverse tissue remodeling after a heart attack or myocardial infarction (MI) is critical to prevent the development of heart failure. Among various post-MI treatment strategies, mechanical reinforcement of the infarcted region with epicardial patches has promise due to its consistent improvement of chronic cardiac function and its drug- or biologic-free nature. However, despite the variety of patch materials studied to date, the lack of a programmable platform that predictably modifies early-stage cardiac biomechanics to different degrees has prevented further optimization of this strategy. Here, we introduce the matrix-mimicking bioadhesive epicardium (MMBE), a platform that can be rationally designed to achieve a wide range of anisotropic mechanical properties to offer quantifiable mechanical reinforcement of the heart upon application. The platform synergistically combines fully programmable direct-ink-writing of extracellular matrix-inspired crimped fibers and a bioadhesive for sutureless integration to the epicardium. The MMBE platform achieves an array of matrix-mimicking mechanical properties and acute modulation of cardiac biomechanics using numerical analysis, in silico studies and experimental characterizations. Furthermore, the feasibility of the MMBE platform in an in vivo rat model of MI is demonstrated. The MMBE platform can be used to systematically identify patch design parameters that alter post-MI remodeling without introducing confounding biological variables.

bioengineering↗

bioRxiv2025

A scalable proteogenomic framework for dissecting phospho-signaling pathways in primary immune cells

Signaling networks modulated by post-translational modifications orchestrate cellular responses to external cues. Traditional approaches to study these pathways lack the throughput to systematically capture the causal architecture of these signaling pathways at scale. Here, we present an integrated proteogenomic framework that combines saturating genetic perturbations with high-throughput proteomics to systematically map cytokine-induced signaling in primary human T cells. Supporting this framework is simplePhos, a streamlined, low-input phosphoproteomics workflow that enables scalable, time-resolved analysis without the requirement for specialized equipment or robotics. We extensively validate the simplePhos pipeline by applying inflammatory stimuli, including type I and II interferons, lipopolysaccharide, and Sendai virus to primary T cells and myeloid cells, establishing foundational datasets in these treatment contexts. Ultimately, using type I interferon signaling in genetically modified T cells as a model, we demonstrate that combined application of genetic alterations and proteomic analyses can map key signaling nodes in primary immune cells. This represents a powerful strategy to mechanistically interrogate phospho-signaling networks in human immune cells, with broad applications in translational immunology and therapeutic development.

systems biology↗

bioRxiv2025

Phosphorylation-State Modulated Binding of HSP70: Structural Insights and Compensatory Protein Engineering

Protein quality control is crucial for cellular homeostasis, involving the heat shock response, the ubiquitin-proteasome system, and the autophagy-lysosome pathway. Central to these systems are the chaperone homologs heat shock protein 70 (HSP70) and heat shock cognate 70 (HSC70), which manage protein folding and degradation. This study investigated the impact of the C-terminal phosphorylation of HSP70 on its interaction with the co-chaperone CHIP (C-terminus of HSC70 interacting protein), an E3 ligase that ubiquitinates protein substrates for degradation. Using both cell-free and cell-based approaches, including X-ray crystallography, biolayer interferometry, and live cell biocomplementation assays, we demonstrate that phosphorylation at HSP70 T636 reduces CHIPs binding affinity, shifting the preference toward other co-chaperones like HOP. Structural analysis reveals that phosphorylation disrupts key hydrogen bonds, altering binding dynamics. We engineered a CHIP variant (CHIP-G132N) to restore binding affinity to phosphorylated HSP70. While CHIP-G132N effectively restored binding without additional functional domains, its effectiveness was diminished in full-length phosphomimetic constructs in cell-free and in-cell assays, suggesting that additional interactions may influence binding. Functional assays indicate that phosphorylation of HSP70 affects its stability and degradation, with implications for diseases such as cancer and neurodegeneration. Our findings highlight the complexity of chaperone-co-chaperone interactions and underscore the importance of post-translational modifications in regulating protein quality control mechanisms. By elucidating the molecular details of HSP70 and CHIP interactions, our study provides a foundation for developing therapeutic interventions for diseases characterized by proteostasis imbalance.

biochemistry↗

bioRxiv2023

Simultaneous detection of membrane contact dynamics and associated Ca2+ signals by reversible chemogenetic reporters

Membrane contact sites (MCSs) are hubs allowing various cell organelles to coordinate their activities. The dynamic nature of these sites and their small size hinder analysis by current imaging techniques. To overcome these limitations, we here designed a series of reversible chemogenetic reporters incorporating improved, low-affinity variants of splitFAST, and studied the dynamics of different MCSs at high spatiotemporal resolution, both in vitro and in vivo. We demonstrated that these versatile reporters suit different experimental setups well, allowing one to address challenging biological questions. Using these novel probes, we identified a hitherto unknown pathway, in which calcium (Ca2+) signalling dynamically regulates endoplasmic reticulum-mitochondria juxtaposition, characterizing the underlying mechanism. Finally, by integrating Ca2+-sensing capabilities into the splitFAST technology, we introduced PRINCESS (PRobe for INterorganelle Ca2+-Exchange Sites based on SplitFAST), an unprecedented class of reporters to simultaneously detect MCSs and measure the associated Ca2+ dynamics using a single biosensor.

cell biology↗

bioRxiv2023

Comparative Analysis, Diversification and Functional Validation of Plant Nucleotide-Binding Site Domain Genes

Nucleotide-binding site (NBS) domain genes are one of a superfamily of resistance genes involved in plant responses to pathogens. The current study identified presumably identified 12,820 NBS-containing genes across 34 species covering from mosses to monocots and dicots. These identified genes classified into 168 classes with several novel domain architectures patterns encompassing significant diversity among plant species. Several classical (NBS, NBS-LRR, TIR-NBS, TIR-NBS-LRR etc.) and species-specific structural patterns (TIR-NBS-TIR-Cupin_1-Cupin_1, TIR-NBS-Prenyltransf, Sugar_tr-NBS etc.) were discovered. We observed 603 orthogroups (OGs) with some core (most common orthogroups; OG0, OG1, OG2 etc.) and unique (highly specific to species; OG80, OG82 etc) OGs with tandem duplications. The expression profiling presented the putative upregulation of OG2, OG6, and OG15 in different tissues under various biotic and abiotic stresses in susceptible and tolerant plants to CLCuD. The genetic variation between susceptible (Coker 312) and tolerant (Mac7) G. hirsutum accessions identified several unique variants in NBS genes of Mac7 (6,583 varaints) and Coker312 (5,173 variants). The protein-ligand and proteins-protein interaction showed a strong interaction of some putative NBS proteins with ADP/ATP and different core proteins of cotton leaf curl disease virus. The silencing of GaNBS (OG2) in resistant cotton through virus-induced gene silencing (VIGS) demonstrated its putative role in virus tittering. The presented study will be further helpful to understand the plant adaptation mechanism.

plant biology↗

bioRxiv2023

Soft robotics-enabled large animal model of HFpEF hemodynamics for device testing

Heart failure with preserved ejection fraction (HFpEF) is a major challenge in cardiovascular medicine, accounting for approximately 50% of all cases of heart failure. Due to the lack of effective therapies for this condition, the mortality associated with HFpEF remains higher than that of most cancers. Despite the ongoing efforts, no medical device has yet received FDA approval. This is largely due to the lack of an in vivo model of the HFpEF hemodynamics, resulting in the inability to evaluate device effectiveness in vivo prior to clinical trials. Here, we describe the development of a highly tunable porcine model of HFpEF hemodynamics using implantable soft robotic sleeves, where controlled actuation of a left ventricular and an aortic sleeve can recapitulate changes in ventricular compliance and afterload associated with a broad spectrum of HFpEF hemodynamic phenotypes. We demonstrate the feasibility of the proposed model in preclinical testing by evaluating the hemodynamic response of the model post-implantation of an interatrial shunt device, which was found to be consistent with findings from in silico studies and clinical trials. This work addresses several of the limitations associated with previous models of HFpEF, such as their limited hemodynamic fidelity, elevated costs, lengthy development time, and low throughput. By showcasing exceptional versatility and tunability, the proposed platform has the potential to revolutionize the current approach for HFpEF device development and selection, with the goal of improving the quality of life for the 32 million people affected by HFpEF worldwide.

bioengineering↗

bioRxiv2023

High dimensional analyses reveal activation of lymphocyte subsets and reversal of immunoresistance by cytokine enhancement of adoptive cellular vaccine therapy in prostate cancer.

Engineered cell therapies have emerged as a potent therapeutic option for the hematologic malignancies, however solid tumor responses to similar approaches have been modest. The outlier is Sipuleucel-T (sip-T), an FDA-approved autologous cellular immunotherapy for metastatic castration-resistant prostate cancer (mCRPC). To elucidate parameters of the response profile to this therapy, we report the first high dimensional cellular analyses of sip-T using mass cytometry (CyTOF) and show a lymphoid predominance, with CD3+ T cells constituting the highest proportion (median [~]60%) of sip-T, followed by B-cells, and natural killer (NK) and NKT cells. We hypothesized that treatment of sip-T with homeostatic cytokines known to activate/expand effector lymphocytes could augment efficacy against prostate cancer. Of cytokines tested, IL-15 treated sip-T showed the most significant activation and proliferation of effector lymphocytes, as well as augmentation of tumor cytotoxicity in vitro. Co-culture of sip-T with IL-15 and control or prostate-relevant antigens showed significant activation and expansion of CD8 T and NKT cells in an antigen-specific manner. Adoptive transfer of IL-15 treated sip-T into NSG mice resulted in potent prostate tumor growth inhibition compared with control sip-T. Evaluation of tumor-infiltrating lymphocytes revealed a 2 to 14-fold higher influx of sip-T and a significant increase in interferon (IFN)-{gamma} producing CD8+ T and NKT cells within the tumor microenvironment (TME) in the IL-15 group. In conclusion, we put forward the first evidence that IL-15 treatment can enhance the functional anti-tumor efficacy of sip-T, providing rationale for combining IL-15 or IL-15 agonists with sip-T to treat mCRPC patients. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=138 SRC="FIGDIR/small/550213v1_ufig1.gif" ALT="Figure 1"> View larger version (34K): org.highwire.dtl.DTLVardef@130adb0org.highwire.dtl.DTLVardef@db2567org.highwire.dtl.DTLVardef@174a953org.highwire.dtl.DTLVardef@18c049_HPS_FORMAT_FIGEXP M_FIG C_FIG One sentence summaryIL-15 treatment can enhance the efficacy/anti-tumor immunity of sipuleucel-T by modulating CD8+ T-cell and CD56+ NKT subsets.

immunology↗

bioRxiv2023

Adult-onset CNS sulfatide deficiency causes sex-dependent metabolic disruption in aging

The interconnection between obesity and central nervous system (CNS) neurological dysfunction has been widely appreciated. Accumulating evidence demonstrates that obesity is a risk factor for CNS neuroinflammation and cognitive impairment. However, the extent to which CNS disruption influences peripheral metabolism remains to be elucidated. We previously reported that myelin-enriched sulfatide loss leads to CNS neuroinflammation and cognitive decline. In this study, we further investigated the impact of CNS sulfatide deficiency on peripheral metabolism while considering sex- and age-specific effects. We found that female sulfatide-deficient mice gained significantly more body weight, exhibited higher basal glucose levels, and were glucose intolerant during glucose-tolerance test (GTT) compared to age-matched controls under a normal diet, whereas male sulfatide-deficient mice only displayed glucose intolerance at a much older age compared to female sulfatide-deficient mice. Mechanistically, we found the increased body weight was associated with increased food intake and elevated neuroinflammation, especially in the hypo-thalamus, in a sex-specific manner. Our results suggest that CNS sulfatide deficiency leads to sex-specific alterations in energy homeostasis via dysregulated hypothalamic control of food-intake.

neuroscience↗

bioRxiv2023

The HLA-II immunopeptidome of SARS-CoV-2

Targeted synthetic vaccines have the potential to transform our response to viral outbreaks; yet the design of these vaccines requires a comprehensive knowledge of viral immunogens, including T-cell epitopes. Having previously mapped the SARS-CoV-2 HLA-I landscape, here we report viral peptides that are naturally processed and loaded onto HLA-II complexes in infected cells. We identified over 500 unique viral peptides from canonical proteins, as well as from overlapping internal open reading frames (ORFs), revealing, for the first time, the contribution of internal ORFs to the HLA-II peptide repertoire. Most HLA-II peptides co-localized with the known CD4+ T cell epitopes in COVID-19 patients. We also observed that two reported immunodominant regions in the SARS-CoV-2 membrane protein are formed at the level of HLA-II presentation. Overall, our analyses show that HLA-I and HLA-II pathways target distinct viral proteins, with the structural proteins accounting for most of the HLA-II peptidome and non-structural and non-canonical proteins accounting for the majority of the HLA-I peptidome. These findings highlight the need for a vaccine design that incorporates multiple viral elements harboring CD4+ and CD8+ T cell epitopes to maximize the vaccine effectiveness.

microbiology↗