Biology subjects

Tang, H.-Y.

Publications and source records attributed to Tang, H.-Y..

At least 19 recordsLinked to original sources

bioRxiv2026

NAD Metabolism Drives CTCF-Cohesin Chromatin Regulation in EBV-Transformed B-Cells

Chromatin architecture regulates gene expression, and it is maintained by architectural proteins such as CTCF and the cohesin complex. In Epstein Barr virus infected cells, viral chromatin organization is stabilized through the interaction between PARP1 and CTCF, ensuring maintenance of latent gene expression. EBV B cells exhibit elevated PARP1 activity, which imposes a substantial metabolic burden due to NAD consumption by PARP1 itself. We demonstrate that efficient EBV infection and B-cell transformation rely on the NAD salvage pathway to sustain PARP1 activity and CTCF and cohesin chromatin folding. Pharmacologic inhibition of the rate-limiting enzyme NAMPT with FK866 phenocopies the chromatin architectural disruption induced by PARP1 and changes in NAD levels affects CTCF/cohesin chromatin architectural remodeling and loop extrusion. Moreover, NAMPT inhibition reduces tumor burden in EBV xenograft models. These findings identify a critical metabolic dependency linking NAD homeostasis to CTCF-cohesin mediated chromatin architecture and reveal a therapeutic vulnerability in EBV-associated malignancies.

microbiology↗

bioRxiv2026

Tyrosine phosphorylation and dimerization cooperatively activate NAMPT to enable NAD+ synthesis in cancer

Nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme in the NAD salvage pathway, is frequently upregulated in cancer, yet mechanisms regulating its catalytic activity remain undefined. We identify NAMPT as a direct substrate of multiple proto-oncogenic tyrosine kinases, including ALK, insulin receptor, IGF1R, and PDGFRA. Phosphoproteomics identified NAMPT Y188 as the major phosphorylation site, including the oncogenic fusion kinase NPM1::ALK. NAMPT interacted with NPM1::ALK in the cytoplasm, nucleus, and mitochondria, while Y188 phosphorylation enhanced catalytic activity, NMN/NAD biosynthesis, and downstream metabolism. Conversely, the Y188F mutant reduced enzymatic activity, proliferation, and clonogenicity, whereas disrupting dimerization similarly impaired phosphorylation and function. Interactome analyses showed phosphorylation and dimerization cooperatively remodel NAMPT-associated networks, enriching phosphorylated dimers for metabolic/redox regulators and monomeric NAMPT for ribosome biogenesis. NAMPT inhibition suppressed the growth of both ALK inhibitor-sensitive and -resistant lymphoma cells and enhanced the efficacy of ALK inhibition, revealing kinase-dependent NAMPT activation as a metabolic vulnerability in oncogene-driven cancers.

cancer biology↗

bioRxiv2026

The trypanosomatid dynamin-like protein associates with glycosomes

Subcellular organelles must undergo periodic fission to be evenly distributed during cell division. These division events are mediated by protein members of the dynamin family, including dynamin-related proteins. Protozoan parasites, including trypanosomatids such as Trypanosoma brucei, have several single-copy organelles, suggesting tightly regulated systems for organelle fission and segregation. However, trypanosomatid genomes typically encode only one dynamin-like protein (DLP), which in T. brucei has multiple roles including endocytosis and mitochondrial fission. How DLPs are recruited to different membranes, and how their fission activity is regulated, are unknown. We used tandem-affinity purification in the related trypanosomatid Crithidia fasciculata to identify interacting partners of DLP. Surprisingly, we found that CfDLP co-purified with multiple proteins predicted to localize to glycosomes, peroxisome-related glycolytic organelles. Using expansion microscopy, we confirmed the localization of CfDLP to glycosomes, specifically those that appear to be undergoing division. To see if changes in the levels of DLP could alter glycosome morphology, we conducted RNAi-mediated knockdown and inducible overexpression experiments in T. brucei. TbDLP knockdown causes subtle changes in glycosome size, while overexpression of TbDLP1 causes an increase cytoplasmic vesicles and altered permeability of glycosomal membranes. These results suggest that the multifunctional DLP of trypanosomatids plays a role in glycosome maintenance. Author SummaryTrypanosomatids are eukaryotic parasites that cause devastating diseases in humans and animals. Like all eukaryotic cells, they must maintain their subcellular compartments through organelle division and other membrane remodeling events. Dynamin-like proteins are enzymes that work with other proteins to apply mechanical force to membranes. The dynamin-like proteins of Trypanosoma brucei, the causative agent of human African trypanosomiasis, have been implicated in endocytosis and mitochondrial division, although how these activities are regulated is not known. We have used a model trypanosomatid, the mosquito parasite Crithidia fasciculata, to look for dynamin-interacting proteins. In addition to proteins of unknown function, we show that dynamin-like protein associates with proteins found on glycosomes, trypanosomatid-specific organelles that contain enzymes required for breakdown of sugars. Knockdown and overexpression of dynamin-like proteins in T. brucei causes changes in glycosomes, supporting a role in organelle maintenance. Dynamin-like proteins likely regulate organelle structure and function, allowing parasites to adapt to different energetic requirements during their life cycle.

cell biology↗

bioRxiv2026

It's Not Rewarding for Mitochondria: Dopamine-Induced Mitochondrial Dysfunction Activates cGAS-STING to Drive IL-6 Secretion in Macrophages

Despite increasing data demonstrating dopamine as an inflammatory mediator of the innate immune system, the molecular mechanisms underlying its effects in human cells remain incompletely defined. Here, we define an unrecognized pathway in which dopamine induces robust IL-6 secretion in primary human monocyte-derived macrophages (hMDMs) through mitochondrial stress. Dopamine initiates a transient mitochondrial membrane depolarization that leads to sustained alterations in mitochondrial dynamics, including morphology and metabolism, in a time-dependent manner. These events promote the mtDNA release into the cytoplasm, triggering cGAS-STING pathway and downstream NF-{kappa}B signaling. Pharmacological inhibition at multiple nodes of this pathway attenuates IL-6 secretion, establishing mitochondrial dysfunction and cGAS-STING signaling as central mediators of dopamine-driven IL6 secretion. Variability in dopamine receptor expression across donors correlates with the magnitude of IL-6 responses. Together, these findings redefine the interface between dopamine signaling and systemic inflammation and highlight an unrecognized source of inter-individual variation in immune responses. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=171 SRC="FIGDIR/small/719926v1_ufig1.gif" ALT="Figure 1"> View larger version (47K): org.highwire.dtl.DTLVardef@e2c133org.highwire.dtl.DTLVardef@fa0a15org.highwire.dtl.DTLVardef@1ac1f91org.highwire.dtl.DTLVardef@14c8c53_HPS_FORMAT_FIGEXP M_FIG C_FIG Dopamine induces mitochondrial dysfunction mediated through dopamine receptors signaling. This includes alterations in mitochondrial membrane potential, leading to excessive DRP1-mediated mitochondrial fission, increased production of mitochondrial superoxide, and metabolic reprogramming toward enhanced glycolysis with reduced oxidative phosphorylation. Sustained mitochondrial damage is further exacerbated by impaired mitophagy, resulting in the release of mitochondrial DNA (mtDNA) into the cytoplasm. Cytosolic mtDNA, acting as a double-stranded DNA ligand, activates the cGAS-STING pathway, which subsequently induces NF-{kappa}B signaling, ultimately driving the production and secretion of the pro-inflammatory cytokine IL-6. Created on Biorender.com.

immunology↗

bioRxiv2026

HSPB8 regulates CTP synthase filaments to couple nucleotide metabolism and autophagy in tumors

Metabolic adaptation and proteostasis are essential for tumor survival under nutrient stress, yet how these processes are mechanistically integrated remains unclear. Here, we identify CTP synthase (CTPS) filament dynamics as a regulatory nexus linking nucleotide metabolism to autophagic flux. Under glutamine deprivation--a hallmark of poorly vascularized solid tumors--CTPS undergoes polymerization into filamentous assemblies that exhibit reduced enzymatic activity. We demonstrate that filament formation is driven by intracellular asparagine availability and stabilized by the accumulation of misfolded proteins. Using APEX2-based proximity labeling and proteomics, we identify the small heat shock protein HSPB8 as a filament-associated regulator. HSPB8, acting within the chaperone-assisted selective autophagy (CASA) pathway, antagonizes CTPS polymerization by promoting clearance of misfolded proteins, thereby restoring soluble, catalytically active CTPS. Filament disassembly increases CTP production and enhances synthesis of autophagy-related phospholipids, including phosphatidylinositol and phosphatidylethanolamine, resulting in accelerated autophagic flux. Cells expressing filament-deficient CTPS mutants display elevated autophagosome formation and increased LC3-II accumulation upon lysosomal blockade, confirming enhanced flux. In vivo, disruption of CTPS filament assembly impairs xenograft tumor growth and is associated with excessive autophagy. Analysis of TCGA datasets further reveals that high CTPS and low HSPB8 expression correlate with poor patient survival across multiple cancers. Collectively, our findings establish CTPS filament dynamics as a proteostasis-sensitive metabolic switch that coordinates nucleotide biosynthesis with autophagy, revealing a previously unrecognized vulnerability in tumors adapting to nutrient limitation.

cell biology↗

bioRxiv2025

Defining the impact of rRNA processing on nucleolar organization and function

The eukaryotic nucleolus is a highly organized, multilayered structure essential for ribosomal RNA (rRNA) processing and ribosome assembly. However, how the sequential steps of rRNA maturation, particularly the series of endonucleolytic cleavages, contribute to maintaining nucleolar architecture remains poorly understood. Here, we show that disruption of pre-rRNA processing, especially impaired cleavage of the 5' external transcribed spacer (5'ETS), profoundly alters nucleolar organization. Specifically, defects in 5'ETS processing lead to the formation of a single large DAPI-negative nuclear structure and result in the mislocalization of nascent RNA, which diffuses throughout the disorganized nucleolus. These aberrant nucleoli exhibit a distinct proteomic profile, including downregulation of factors involved in splicing, cell cycle regulation, and chromatin organization, suggesting that the impact of nucleolar disorganization extends beyond ribosome biogenesis. Notably, we also observe mislocalization of heterochromatin markers, pointing to broader disruptions in nuclear architecture and gene regulation. Together, our findings reveal that proper 5'ETS cleavage is critical for preserving nucleolar compartmentalization and highlight the tight coupling between rRNA processing and nuclear organization.

molecular biology↗

bioRxiv2025

Targeting Siglec-10/α3β1 Integrin Interactions Enhances Macrophage-Mediated Phagocytosis of Pancreatic Cancer

Tumor-associated macrophages (TAMs) in the pancreatic ductal adenocarcinoma (PDAC) tumor microenvironment (TME) exhibit immunosuppressive phenotypes and impaired phagocytic activity, facilitating tumor progression and immune evasion. Here, we identify integrin 3{beta}1, composed of ITGA3 and ITGB1 subunits, as a sialylated glycoprotein ligand for Siglec-10, an inhibitory glyco-immune checkpoint receptor highly expressed on TAMs in PDAC. The interaction between Siglec-10 on TAMs and 3{beta}1 on PDAC cells suppresses macrophage-mediated phagocytosis, thereby promoting immune evasion. Consistently, disrupting Siglec-10 interactions with monoclonal antibodies significantly enhances macrophage phagocytosis of PDAC cells and alleviates myeloid cell-mediated inhibition of T cell proliferation and activation in vitro. In both a PDAC xenograft mouse model engrafted with human macrophages and a human Siglec-10 transgenic mouse model, targeting Siglec-10 with monoclonal antibodies reduces PDAC tumor growth. These findings suggest that Siglec-10 interactions are key mediators of TAM-driven immune evasion in PDAC and highlight the therapeutic potential of targeting these interactions to restore anti-tumor immunity. SIGNIFICANCEPancreatic tumor cells exploit integrin 3{beta}1 to engage the immunosuppressive checkpoint receptor Siglec-10 on myeloid cells, driving immune evasion, and antibody-mediated blockade of Siglec-10 restores myeloid cell-mediated anti-PDAC immunity.

immunology↗

bioRxiv2024

Ex vivo and in vivo HIV-1 latency reversal by Mukungulu, a protein kinase C-activating African medicinal plant extract

Current HIV latency reversing agents (LRAs) have had limited success in clinic, indicating the need for new strategies that can reactivate and/or eliminate HIV reservoirs. "Mukungulu," prepared from the bark of Croton megalobotrys Mull. Arg., is traditionally used for HIV/AIDS management in Northern Botswana despite containing an abundance of protein kinase C (PKC)-activating phorbol esters ("namushens"). Here we show that Mukungulu is tolerated in mice at up to 12.5 mg/kg while potently reversing latency in antiretroviral therapy (ART)-suppressed HIV-infected humanized mice at 5 mg/kg. In peripheral blood mononuclear cells (PBMC) and isolated CD4+ T-cells from ART-suppressed people living with HIV-1, 1 {micro}g/mL Mukungulu reverses latency on par with or superior to anti-CD3/CD28 positive control, as measured by HIV gag-p24 protein expression, where the magnitude of HIV reactivation in PBMC corresponds to intact proviral burden levels in CD4+ T-cells. Bioassay-guided fractionation identifies 5 namushen phorbol ester compounds that reactivate HIV expression, yet namushens alone do not match Mukungulus activity, suggesting additional enhancing factors. Together, these results identify Mukungulu as a robust natural LRA which may warrant inclusion in future LRA-based HIV cure and ART-free remission efforts.

microbiology↗

bioRxiv2023

Molecular Basis for Maternal Inheritance of Human Mitochondrial DNA

Uniparental inheritance of mitochondrial DNA (mtDNA) is an evolutionary trait found in nearly all eukaryotes. In many species, including humans, the sperm mitochondria are introduced to the oocyte during fertilization1, 2. The mechanisms hypothesized to prevent paternal mtDNA transmission include ubiquitination of the sperm mitochondria and mitophagy3, 4. However, whether these mechanisms play a decisive role in paternal mtDNA elimination has been disputed5, 6. We found that mitochondria in human spermatozoa are devoid of mtDNA and lack mitochondrial transcription factor A (TFAM), the major nucleoid protein required to protect, maintain, and transcribe mtDNA. During spermatogenesis, sperm cells express an isoform of TFAM, which retains the mitochondrial pre-sequence, ordinarily removed upon mitochondrial import. Phosphorylation of this pre-sequence prevents mitochondrial import and directs TFAM to the spermatozoon nucleus. TFAM re-localization from the mitochondria of spermatogonia to the spermatozoa nucleus directly correlates with the elimination of mitochondrial DNA, thereby explaining maternal inheritance in this species.

molecular biology↗

bioRxiv2023

Sexually dimorphic RNA helicases DDX3X and DDX3Y differentially regulate hollow condensates of DDX3X disease variants

Mutations in the RNA helicase DDX3X, implicated in various cancers and neurodevelopmental disorders, often impair RNA unwinding and translation. However, the mechanisms underlying this impairment and the differential interactions of DDX3X mutants with wild-type (WT) X-linked DDX3X and Y-linked homolog DDX3Y remain elusive. This study reveals that specific DDX3X mutants more frequently found in disease form distinct hollow condensates in cells. Using a combined structural, biochemical, and single-molecule microscopy study, we show that reduced ATPase and RNA release activities contribute to condensate formation and the catalytic deficits result from inhibiting the catalytic cycle at multiple steps. Proteomic investigations further demonstrate that these hollow condensates sequester WT DDX3X/DDX3Y and other proteins crucial for diverse signaling pathways. WT DDX3X enhances the dynamics of heterogeneous mutant/WT hollow condensates more effectively than DDX3Y. These findings offer valuable insights into the catalytic defects of specific DDX3X mutants and their differential interactions with wild-type DDX3X and DDX3Y, potentially explaining sex biases in disease.

molecular biology↗

bioRxiv2022

Steric-free bioorthogonal profiling of cellular acetylation and glycosylation via a fluorine-selenol displacement reaction (FSeDR)

Global detection and identification of protein post-translational modification (PTM) is a major bottleneck due to its dynamic property and rather low abundance. Tremendous efforts have been since made to develop antibody-based immunoaffinity enrichment or bioorthogonal chemistry-based chemical reporter approach but both suffer from inherent limitations. Following our previously reported steric-free tagging strategy, we hereby report the invention of selenol as a new generation of fluorine-displacement probe. The fluorine-selenol based displacement reaction enabled us to efficiently label and image acetylation and glycosylation at cellular level. We further pursued FSeDR in tandem with SILAC based quantitative proteomics to globally profile acetylation substrate proteins in a representative prostate cancer cell line PC3. Our results unraveled the fluorine-based toolbox for powerful chemical biology probing and allow for the future study of PTMs in a systemic manner.

cell biology↗

bioRxiv2022

Markers of Fungal Translocation Are Elevated During Post-Acute Sequelae of SARS-CoV-2 Infection and Induce NF-κB Triggered Inflammation.

Long COVID, a type of Post-Acute Sequelae of SARS CoV-2 infection (PASC), has been associated with sustained elevated levels of immune activation and inflammation. However, the pathophysiological mechanisms that drive this inflammation remain unknown. Inflammation during acute Coronavirus Disease 2019 (COVID-19) could be exacerbated by microbial translocation (from the gut and/or lung) to the blood. Whether microbial translocation contributes to inflammation during PASC is unknown. We found higher levels of fungal translocation - measured as {beta}-glucan, a fungal cell wall polysaccharide - in the plasma of individuals experiencing PASC compared to those without PASC or SARS-CoV-2 negative controls. The higher {beta}-glucan correlated with higher levels of markers of inflammation and elevated levels of host metabolites involved in activating N-Methyl-D-aspartate receptors (such as metabolites within the tryptophan catabolism pathway) with established neuro-toxic properties. Mechanistically, {beta}-glucan can directly induce inflammation by binding to myeloid cells (via the Dectin-1 receptor) and activating Syk/NF-{kappa}B signaling. Using an in vitro Dectin-1/NF-{kappa}B reporter model, we found that plasma from individuals experiencing PASC induced higher NF-{kappa}B signaling compared to plasma from SARS-CoV-2 negative controls. This higher NF-{kappa}B signaling was abrogated by the Syk inhibitor Piceatannol. These data suggest a potential targetable mechanism linking fungal translocation and inflammation during PASC.

microbiology↗

bioRxiv2022

Regulation of EBNA1 Protein Stability by PLOD1 Lysine Hydroxylase

Epstein-Barr virus (EBV) is a ubiquitous human {gamma}-herpesvirus that is causally associated with various malignancies and autoimmune disease. Epstein-Barr Nuclear Antigen 1 (EBNA1) is the viral-encoded DNA binding protein required for viral episome maintenance and DNA replication during latent infection in proliferating cells. EBNA1 is known to be a highly stable protein, but its mechanism of protein stability is not completely understood. Proteomic analysis of EBNA1 revealed interaction with Procollagen Lysine-2 Oxoglutarate 5 Dioxygenase (PLOD) family of proteins. Depletion of PLOD1 by shRNA or inhibition with small molecule inhibitors 2,-2 dipyridyl resulted in the loss of EBNA1 protein levels, along with a selective growth inhibition of EBV-positive lymphoid cells. PLOD1 depletion also caused a loss of EBV episomes from latently infected cells and inhibited oriP-dependent DNA replication. We used mass spectrometry to identify EBNA1 peptides with lysine hydroxylation at K460 or K461. Mutation of K460 to alanine or arginine abrogates EBNA1-driven DNA replication of oriP, while K461 mutations enhanced replication. These findings suggest that PLOD1 is a novel post-translational regulator of EBNA1 protein stability and function in viral plasmid replication, episome maintenance and host cell survival. ImportanceEBNA1 is essential for EBV latent infection and implicated in viral pathogenesis. We found that EBNA1 interacts with PLOD family of lysine hydroxylases and that this interaction is required for EBNA1 protein stability and function in viral persistence during viral latent infection. Identification of PLOD1 regulation of EBNA1 protein stability provide new opportunity to target EBNA1 for degradation in EBV associated disease.

molecular biology↗

bioRxiv2021

Protein Posttranslational Signatures Identified in COVID-19 Patient Plasma

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is a highly contagious virus of the coronavirus family that causes coronavirus disease-19 (COVID-19) in humans and a number of animal species. COVID-19 has rapidly propagated in the world in the past 2 years, causing a global pandemic. Here, we performed proteomic analysis of plasma samples from COVID-19 patients compared to healthy control donors in an exploratory study to gain insights into protein-level changes in the patients caused by SARS-CoV-2 infection and to identify potential proteomic and posttranslational signatures of this disease. Our results suggest a global change in protein processing and regulation that occurs in response to SARS-CoV-2, and the existence of a posttranslational COVID-19 signature that includes an elevation in threonine phosphorylation, a change in glycosylation, and a decrease in arginylation, an emerging posttranslational modification not previously implicated in infectious disease. This study provides a resource for COVID-19 researchers and, longer term, will inform our understanding of this disease and its treatment. Key PointsO_LIPlasma from COVID-19 patients exhibits prominent protein- and peptide-level changes C_LIO_LIProteins from COVID-19 patient plasma exhibit prominent changes in several key posttranslational modifications C_LI

biochemistry↗

bioRxiv2021

Differential N-terminal processing of beta and gamma actin in vivo

Actin is one of the most essential and abundant intracellular proteins, playing an essential physiological role as the major constituent of the actin cytoskeleton. Two cytoplasmic actins, beta- and gamma-actin, are encoded by different genes, but their amino acid sequences differ only by four conservative substitutions at the N-terminus, making it very difficult to dissect their individual regulation in vivo. The majority of actins are N-terminally acetylated, following the removal of N-terminal Met. Here, we analyzed beta and gamma cytoplasmic actin N-termini in vivo and found that beta actin, unlike gamma actin, specifically undergoes sequential removal of N-terminal amino acid Asp residues. This processing affects [~]1-3% of beta actin in different cell types. We identified candidate enzymes capable of mediating this type of processing, and used CRISPR/Cas-9 to delete them, individually or together, in mammalian cell lines. This deletion abolishes most of the beta actin N-terminal processing and results in changes in F-actin levels, cell spreading, filopodia formation, and cell migration, suggesting that the beta actin processing mediated by these enzymes is physiologically important to beta actin function. We propose that selective N-terminal processing of beta actin by sequential removal of Asp contributes to differentiating the functions of non-muscle actin isoforms in vivo.

cell biology↗

bioRxiv2020

Glycolysis downregulation is a hallmark of HIV-1 latency and sensitizes infected cells to oxidative stress

HIV-1 infects lymphoid and myeloid cells, which can harbor a latent proviral reservoir responsible for maintaining lifelong infection. Glycolytic metabolism has been identified as a determinant of susceptibility to HIV-1 infection, but its role in the development and maintenance of HIV-1 latency has not been elucidated. By combining transcriptomic, proteomic and metabolomic analysis, we here show that transition to latent HIV-1 infection downregulates glycolysis, while viral reactivation by conventional stimuli reverts this effect. Decreased glycolytic output in latently infected cells is associated with downregulation of NAD+/NADH. Consequently, infected cells rely on the parallel pentose phosphate pathway and its main product, the antioxidant NADPH, fueling antioxidant pathways maintaining HIV-1 latency. Of note, blocking NADPH downstream effectors, thioredoxin and glutathione, favors HIV-1 reactivation from latency in lymphoid and myeloid cellular models. This provides a "shock and kill effect" decreasing proviral DNA in cells from people-living-with-HIV/AIDS. Overall, our data show that downmodulation of glycolysis is a metabolic signature of HIV-1 latency that can be exploited to target latently infected cells with eradication strategies.

immunology↗

bioRxiv2020

Phospholipid Metabolism Is Associated with HIV Rebound Upon Treatment Interruption

Lipids are biologically active molecules involved in a variety of cellular processes and immunological functions, including inflammation. It was recently shown that phospholipids and their derivatives, lysophospholipids, can reactivate latent (dormant) tumor cells, causing cancer recurrence. However, the potential link between lipids and HIV latency, persistence, and viral rebound after cessation of antiretroviral therapy (ART) has never been investigated. We explored the links between plasma lipids and the burden of HIV during ART. We profiled the circulating lipidome from the plasma of 24 chronically HIV-infected individuals on suppressive ART who subsequently underwent an analytic treatment interruption (ATI) without concurrent immunotherapies. The pre-ATI viral burden was estimated as time-to-viral-rebound and viral load setpoints post-ATI. We found that higher pre-ATI levels of lysophospholipids, including the pro-inflammatory lysophosphatidylcholine, were associated with faster time-to-viral-rebound and higher viral setpoints upon ART cessation. Furthermore, higher pre-ATI levels of the pro-inflammatory byproduct of intestinal lysophosphatidylcholine metabolism, trimethylamine-N-oxide (TMAO), were also linked to faster viral rebound post-ART. Finally, pre-ATI levels of several phosphatidylcholine species (lysophosphatidylcholine precursors) correlated strongly with higher pre-ATI levels of HIV DNA in peripheral CD4+ T cells. Our proof-of-concept data point to phospholipids and lysophospholipids as plausible pro-inflammatory contributors to HIV persistence and rapid post-ART HIV rebound. The potential interplay between phospholipid metabolism and both the establishment and maintenance of HIV latent reservoirs during- and post-ART warrants further investigation. IMPORTANCEThe likelihood of HIV rebound after stopping antiretroviral therapy (ART) is a function of the interplay between the size of HIV reservoirs that persist despite ART and the host immunological and inflammatory factors that modulate these reservoirs. There is a need to comprehensively understand these host factors to develop a strategy to cure HIV infection and prevent viral rebound post-ART. Lipids are important biologically active molecules that are known to mediate several cellular functions, including reactivating latent tumor cells; however, their role in HIV latency, persistence, and post-ART rebound has never been investigated. We observed significant links between higher levels of the pro-inflammatory lysophosphatidylcholine and its intestinal metabolic byproduct, trimethylamine-N-oxide, and both faster time-to-viral rebound and higher viral load setpoint post ART. These data highlight the need for further studies to understand the potential contribution of phosphatidylcholine and lysophosphatidylcholine metabolism in shaping host immunological and inflammatory milieu during- and post-ART.

microbiology↗

bioRxiv2020

Steric-Free Bioorthogonal Labeling of Acetylation Substrates Based on a Fluorine-Thiol Displacement Reaction (FTDR)

We have developed a novel bioorthogonal reaction that can selectively displace fluorine substitutions alpha to amide bonds. This fluorine-thiol displacement reaction (FTDR) allows for fluorinated cofactors or precursors to be utilized as chemical reporters; hijacking acetyltransferase mediated acetylation both in vitro and in live cells, which cannot be achieved with azide- or al- kyne- based chemical reporters. The fluoroacetamide labels can be further converted to biotin or fluorophore tags using FTDR, enabling the general detection and imaging of acetyl substrates. This strategy may lead to a steric-free labeling platform for substrate proteins, expanding our chemical toolbox for functional annotation of post-translational modifications (PTMs) in a systematic manner.

cell biology↗