Biology subjects

Qu, J.

Publications and source records attributed to Qu, J..

At least 55 records · Page 3Linked to original sources

bioRxiv2024

Loss of prohibitin 2 in Schwann cells dysregulates key transcription factors controlling developmental myelination

Schwann cells are critical for the proper development and function of the peripheral nervous system, where they form a mutually beneficial relationship with axons. Past studies have highlighted that a pair of proteins called the prohibitins play major roles in Schwann cell biology. Prohibitins are ubiquitously expressed and versatile proteins. We have previously shown that while prohibitins play a crucial role in Schwann cell mitochondria for long-term myelin maintenance and axon health, they may also be present at the Schwann cell-axon interface during development. Here, we expand on this work, showing that drug-mediated modulation of prohibitins in vitro disrupts myelination and confirming that Schwann cell-specific ablation of prohibitin 2 (Phb2) in vivo results in early and severe defects in peripheral nerve development. Using a proteomic approach in vitro, we identify a pool of candidate PHB2 interactors that change their interaction with PHB2 depending on the presence of axonal signals. Furthermore, we show in vivo that loss of Phb2 in mouse Schwann cells causes ineffective proliferation and dysregulation of transcription factors EGR2 (KROX20), POU3F1 (OCT6) and POU3F2 (BRN2) that are necessary for proper Schwann cell maturation. Schwann cell-specific deletion of Jun, a transcription factor associated with negative regulation of myelination, confers partial rescue of the development defect seen in mice lacking Schwann cell Phb2. This work develops our understanding of Schwann cell biology, revealing that Phb2 may directly or indirectly modulate the timely expression of transcription factors necessary for proper peripheral nervous system development, and proposing candidates that may play a role in PHB2-mediated integration of axon signals in the Schwann cell.

neuroscience↗

bioRxiv2024

Dark-based Optical Sectioning assists Background Removal in Fluorescence Microscopy

A fundamental challenge in fluorescence microscopy is the defocused background caused by scattering light, optical aberration, or limited axial resolution. Severe defocus backgrounds will submerge the in-focus information and cause artifacts in the following processing. Here, we leverage a priori knowledge about dark channels of biological structures and dual frequency separation to develop a single-frame defocus removal algorithm. It stably improves the signal-to-background ratio and structural similarity index measure of images by approximately 10-fold, and recovers in-focus signal with 85% accuracy, even when the defocus background is 50 times larger than in-focus information. Our Dark-based optical sectioning approach (Dark sectioning) is fully compatible with various microscopy techniques, such as wide-filed microscopy, polarized microscopy, laser-scanning / spinning-disk confocal microscopy, stimulated emission depletion microscopy, lightsheet microscopy, and light-field microscopy. It also complements reconstruction or processing algorithms such as deconvolution, structure illumination microscopy, and super-resolution optical fluctuation imaging.

bioinformatics↗

bioRxiv2024

Distinct Escherichia coli transcriptional profiles in the guts of recurrent UTI sufferers revealed by pan-genome hybrid selection

Low-abundance members of microbial communities are difficult to study in their native habitats. This includes Escherichia coli, a minor, but common inhabitant of the gastrointestinal tract and opportunistic pathogen, including of the urinary tract, where it is the primary pathogen. While multi-omic analyses have detailed critical interactions between uropathogenic Escherichia coli (UPEC) and the bladder that mediate UTI outcome, comparatively little is known about UPEC in its pre-infection reservoir, partly due to its low abundance there (<1% relative abundance). To accurately and sensitively explore the genomes and transcriptomes of diverse E. coli in gastrointestinal communities, we developed E. coli PanSelect which uses a set of probes designed to specifically recognize and capture E. colis broad pangenome from sequencing libraries. We demonstrated the ability of E. coli PanSelect to enrich, by orders of magnitude, sequencing data from diverse E. coli using a mock community and a set of human stool samples collected as part of a cohort study investigating drivers of recurrent urinary tract infections (rUTI). Comparisons of genomes and transcriptomes between E. coli residing in the gastrointestinal tracts of women with and without a history of rUTI suggest that rUTI gut E. coli are responding to increased levels of oxygen and nitrate, suggestive of mucosal inflammation, which may have implications for recurrent disease. E. coli PanSelect is well suited for investigations of native in vivo biology of E. coli in other environments where it is at low relative abundance, and the framework described here has broad applicability to other highly diverse, low abundance organisms.

microbiology↗

bioRxiv2024

Proteomics analysis reveals novel phosphorylated residues and associated proteins of the polyomavirus DNA replication initiation complex.

Polyomavirus (PyV) Large T-antigen (LT) is the major viral regulatory protein that targets numerous cellular factors/pathways: tumor suppressors, cell cycle regulators, transcription and chromatin regulators, as well as other factors for viral replication. LT directly recruits the cellular replication factors involved in LTs recognition of the viral origin, origin unwinding, and primer synthesis which is carried out by mutual interactions between LT, DNA polymerase alpha-primase (Polprim), and single strand (ss) DNA binding replication protein A (RPA). The activities as well as interactions of these three with each other as well as other factors, are known to be modulated by post-translational modifications (PTMs); however, modern high-sensitivity proteomic analyses of the PTMs as well as proteins associated with the three have been lacking. Elution from immunoprecipitation (IP) of the three factors were subjected to high-resolution liquid chromatography tandem mass spectrometry (LC-MS/MS). We identified 479 novel phosphorylated amino acid residues (PAARs) on the three factors: 82 PAARs on SV40 LT, 305 on the Polprim heterotetrametric complex and 92 on the RPA heterotrimeric complex. LC-MS/MS analysis also identified proteins that co-immunoprecipitated (coIP-ed) with the three factors that were not previously reported: 374 with LT, 453 with Polprim and 183 with RPA. We used a bioinformatic-based approach to analyze the proteomics data and demonstrate a highly significant "enrichment" of transcription-related process associated uniquely with LT, consistent with its role as a transcriptional regulator, as opposed to Polprim and RPA associated proteins which showed no such enrichment. The most significant cell cycle related network was regulated by ETS proto-oncogene 1 (ETS1), indicating its involvement in regulatory control of DNA replication, repair, and metabolism. The interaction between LT and ETS1 is validated and shown to be independent of nucleic acids. One of the novel phosphorylated aa residues detected on LT from this study, has been demonstrated by us to affect DNA replication activities of SV40 Large T-antigen. Our data provide substantial additional novel information on PAARs, and proteins associated with PyV LT, and the cellular Polprim-, RPA- complexes which will benefit research in DNA replication, transformation, transcription, and other viral and host cellular processes.

microbiology↗

bioRxiv2024

SHP2-triggered endothelium activation fuels estradiol-independent endometrial sterile inflammation

Endometrial hyperplasia (EH) is a common gynecological disease primarily driven by excess estrogen. How endometrial sterile inflammation regulates EH remains unclear. First, we found the upregulation of SHP2 in endometrial endothelial cells from patients with EH by scRNA-Seq. SHP2 promoted inflammatory activation of endothelial cells, which promoted macrophage transendothelial migration. Subsequently, IL1{beta} and TNF from macrophages gave a feedforward loop to enhance endothelial cell activation and result in more IGF1 secretion, thereby sustaining sterile endometrial inflammation and facilitating endometrial epithelial cell proliferation even after estradiol withdrawal. Mechanistically, results of bulk RNA-Seq and phosphoproteomic analyses showed that endothelial SHP2 dephosphorylated RIPK1Y380 after estradiol stimulation. This event promoted activator protein 1 (AP-1) activation, instigating inflammation and increased CXCL10, CXCL13, COX2 and IGF1 secretion. Furthermore, targeting SHP2 by SHP099 or endothelial-specific SHP2 deletion alleviated EH progression in mice. Collectively, our findings demonstrate that SHP2 mediates the transition of endothelial activation, from estradiol-driven short inflammation to macrophage-amplified continuous sterile inflammation. Targeting chronic sterile inflammation mediated by endothelial cell activation is a promising strategy for non-hormonal intervention in EH.

molecular biology↗

bioRxiv2023

Targeted Deletion of All Known Thyroid Hormone Receptors Causes Maturation Retardation and Early-onset Degeneration of Cochlear Outer Sulcus

Thyroid hormone (TH) and its receptors (TRs) are crucial for cochlear late-stage development and endocochlear potential (EP) maintenance. However, the mechanism underlying EP reduction in the absence of TH or TRs remains elusive. Cochlear outer sulcus root cells undergo significant morphological changes during late-stage cochlear development and are believed to play a role in maintaining endolymph homeostasis and EP. Yet, it is unknown whether TH and/or TRs are necessary for root cell differentiation and function. Here, we elucidate the essential role of TH or TRs in postnatal root cell development and survival in mice. TH deficiency significantly delayed root cell differentiation. Otocyst-selective deletion of both Thra and Thrb, but not Thrb alone, leads to a similar impairment, accompanied by early degeneration of root cells, with the stria vascularis remaining unaffected. Furthermore, a 22% reduction in mean EP magnitudes was observed in conditional TRs double knockout mice at 4 months of age, less pronounced than in global TRs knockout mice. Transcriptome analysis reveals that TH deficiency downregulates a significant portion of root cell-enriched genes. These findings underscore the redundant roles of TR and TR{beta} in promoting the late-stage differentiation and survival of root cells. Additionally, they suggest that the expression of TRs in cochlear epithelium is crucial for maintaining an optimal EP magnitude, while TRs expressed in areas outside cochlear epithelium, particularly in spiral ligament fibrocytes, may also significantly contribute to EP maintenance. This study advances our understanding of TH in cochlear outer sulcus development and EP maintenance.

developmental biology↗

bioRxiv2023

Pipeline for RNA sequencing data analysis by combination of Nextflow and R

With the development of high-throughput technologies, RNA sequencing (RNA-seq) has become a widely used technology in biological studies and thus a large number of RNA-seq data are emerging and remain to be analyzed. Although there are many different options for analysis methods and tools, a unified pipeline for RNA-seq data analysis is always necessary for a laboratory. Given the update of new methods and tools, I summarized my customized analysis codes to generate an updated pipeline for RNA-seq data analysis. During aging, gene mutations accumulate, and hormone regulation is disrupted, which may exacerbate age-related diseases. Therefore, we generated a dataset from mice with a gene mutation or not and under different hormone treatments to study the effects of two factors, i.e., hormone and gene mutation, on the transcriptome. Based on the Nextflow nf-core rnaseq pipeline, this project established this pipeline consisting of three stages: (1) upstream analysis containing quality control of fastq files before and after trimming, trimming, alignment, and quantification; (2) midstream analysis containing count normalization, differentially expressed genes analysis, and visualization via boxplot, PCA, t-SNE, sample distance heatmap, MA plot, volcano plot, and gene expression heatmap; and (3) downstream analysis containing functional enrichments of KEGG pathways and GO terms. Results showed distinct effects of the single factor as well as interactive effects of the two factors. Codes are also provided for readers who want to customize their analysis pipeline adapted from this pipeline easily.

bioinformatics↗

bioRxiv2023

DNA damaged-induced phosphorylation of a viral replicative DNA helicase results in inhibition of DNA replication through attenuation of helicase function

A major function of the DNA damage responses (DDRs) that act during the replicative phase of the cell cycle is to inhibit initiation and elongation of DNA replication. The polyomavirus SV40 is an important model system for studying human DNA replication and DDRs due to its heavy reliance on host factors for viral DNA replication, and the arrest of SV40 DNA replication in response to DDR activation. The inhibition of SV40 DNA replication following DDR activation is associated with enhanced DDR kinase phosphorylation of SV40 Large T-antigen (LT), the viral origin-binding protein and DNA helicase. NetPhos prediction of LT phosphorylation on multiple sites were confirmed by mass spectroscopy, including a highly conserved DDR kinase site, T518. In cell-based DNA replication assays expression of the phosphomimetic mutant form of LT at T518 (T518D) resulted in dramatically decreased levels of SV40 DNA replication; while LT-dependent transcriptional activation was unaffected. WT and LT T518D were subsequently expressed, purified, and analyzed in vitro for assessment of biochemical function. In concordance with the cell-based data, reactions using SV40 LT-T518D, but not T518A, showed dramatic inhibition of SV40 DNA replication. Importantly, the LT T518D mutation did not affect critical LT protein interactions or its ATPase function, but showed decreased helicase activity on long, but not very short, DNA templates. These results suggest that DDR phosphorylation at T518 inhibits SV40 DNA replication by impeding LT helicase activity, thereby slowing the DNA replication fork. This is consistent with the slowing of cellular replication forks following DDR and may provide a paradigm for another mechanism for how DNA replication forks can be slowed in response to DDR, by phosphorylation of DNA helicases.

microbiology↗

bioRxiv2023

Cardiac Specific Overexpression of Adenylyl Cyclase 8 Reprograms the Mouse Sinoatrial Node Transcriptome

A coupled-clock system intrinsic to sinoatrial node (SAN) pacemaker cells that regulates the rate and rhythm of spontaneous action potential firing, is activated by Ca2+/calmodulin-stimulated Adenylyl Cyclase (AC) types 8 and 1. Our previous work in mice with cardiac specific overexpression of human AC8 gene (TGAC8) discovered that compared to its wild-type (WT) littermates, the heart rate (HR) of TGAC8 is elevated (by about 30%, 24 hours a day, 7days a week), and that the TGAC8 heart rhythm is markedly coherent, i.e., the HR Variability (HRV) lacks complexity, similar to that associated with aging or cardiac pathology. Reprogramming of molecular mechanisms, particularly SAN transcriptomic regulation that underlies the remarkable chronic shift in HR and HRV, however, has not been delineated. We conducted deep RNA sequencing (RNA-seq) in TGAC8 and WT SANs, using Mm10plus with human ADCY8 DNA sequence as the reference genome. Utilizing multiple bioinformatic techniques, we not only profiled the expression of marker genes related to SAN functions and AC-cAMP-PKA signaling, but also discovered negatively enriched hub pathways that differed in TGAC8 vs. WT, the top three being OXPHOS, ribosome, and cardiac muscle contraction. In contrast, signaling pathways related to inositol phosphate and its metabolism were positively enriched in TGAC8. Further, we identified two transcription regulators, KDM5A and PPARGC1A, that mediate effects of TGAC8 on ribosome and mitochondria. In summary, reprogrammed transcriptional regulation increases the HR of TGAC8 at the cost of impairment of other SAN cell functions, i.e., altered ribosome and inositol phosphate signaling and its crosstalk with mitochondria. Because these cell signaling alterations are associated with cardiac aging and age-associated CVDs, the TGAC8 mouse appears to be an ideal model in which to probe for potential therapeutic targets for cardiac aging and age-associated CVDs.

systems biology↗

bioRxiv2023

ZC3H11A mutations cause high myopia by triggering PI3K-AKT and NF-κB mediated inflammatory reactions in humans and mice

High myopia (HM) is a severe form of refractive error that results in irreversible visual impairment and even blindness. However, the genetic and pathological mechanisms underlying this condition are not yet fully understood. From a cohort of 1015 patients with high myopia in adolescents, likely pathogenic missense mutations were identified in the ZC3H11A gene in four patients by whole exome sequencing. This gene is a zinc finger and stress-induced protein that plays a significant role in regulating nuclear mRNA export. To better understand the function and molecular pathogenesis of myopia in relation to gene mutations, a Zc3h11a knock-out (KO) mouse model was created. The heterozygous KO (Het-KO) mice exhibited significant shifts in refraction towards myopia. Myopia-related factors, including TGF-{beta}1, MMP-2 and IL-6 were found to be upregulated in the retina or sclera, and electroretinography and immunofluorescence staining results showed dysfunction and reduced number of bipolar cells in the retina. Transmission electron microscopy findings suggesting ultrastructural abnormalities of the retina and sclera. Retinal transcriptome sequencing showed that 769 genes were differentially expressed, and Zc3h11a was found to have a negative impact on the PI3K-AKT and NF-{kappa}B signaling pathways by quantitative PCR and western blotting. In summary, this study characterized a new candidate pathogenic gene associated with high myopia, and indicated that the ZC3H11A protein may serve as a stress-induced nuclear response trigger, and its abnormality causes disturbances in a series of inflammatory and myopic factors. These findings offer potential therapeutic intervention targets for controlling the development of HM.

genetics↗

bioRxiv2023

Protective concentric cardiac proteostasis adaptations to chronic cAMP-stress at young ages wanes in advanced age leading to accelerated cardiac aging

Dysregulated proteostasis, leading to accumulation of misfolded proteins, electron-dense aggregates (lipofuscin, LF), preamyloid oligomers (PAOs), and proteotoxic stress is a hallmark of aging. We investigated how efficiently proteostatic adaptations to chronic cardiac cyclic adenosine monophosphate (cAMP)-dependent stress change with aging in mice harboring marked, cardiac-specific over-expression of adenylyl cyclase VIII (TGAC8). We assessed protein quality control (PQC) mechanisms: ubiquitin proteasome system (UPS), autophagic flux via macroautophagy, and mitophagy in left ventricles (LVs) of TGAC8 and wild type littermates (WT) at 3-4 months and at 17-21 months of age. At 3-4 months of age TGAC8 mice exhibited markers of increased autophagic flux, measured by levels of microtubule-associated protein 1 light chain 3 (LC3), p62, and their phospho-forms in TGAC8 LV; cathepsin L1 activity was also significantly increased. In addition, canonical mitophagy signaling was enhanced, as receptors PARKIN, p62S405 and p62S351 were all upregulated, confirming a more efficient proteostasis in TGAC8 at 3-4 months vs WT. In advanced age, however, the PQC mechanisms were overwhelmed by proteotoxic stress, manifested in insufficient proteasome activity and an unbalanced autophagic flux (accelerated for markers such as LC3A in the context of a slower overall flux), leading to an increase in the accumulation of protein aggregates (increased ratio of insoluble/soluble protein fractions). Although both canonical (PARKIN, p62S405 and p62S351 receptors) and non-canonical (FKBP8 receptor) mitophagy signaling were upregulated in advanced age in TGAC8, mitophagy was markedly impaired and mitochondrial dysfunction increased. Accumulation of LF bodies, of brownish-to-black pigments, and of LC3+ and p62+-inclusions of aberrant sizes, of desmin cardiac preamyloid oligomers (PAOs) and of cleaved desmin, tagged for ubiquitination, were all increased in TGAC8 compared to young TGAC8. In contrast, the rate of protein synthesis and levels of soluble aggregates were reduced in aged vs young TGAC8, a sign of "normal" aging. Thus, increased proteostatic mechanisms maintain cardiac health in TGAC8 in youth (3-4 months), but long-term exposure to chronic cardiac stress, imposed by sustained activation of the AC/cAMP/PKA/Ca2+ signaling axis, results in severely dysregulated proteostasis in TGAC8 vs WT mice, associated with proteostatic insufficiency and increased cardiomyopathy that leads to accelerated cardiac aging. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=171 SRC="FIGDIR/small/553128v3_ufig1.gif" ALT="Figure 1"> View larger version (58K): org.highwire.dtl.DTLVardef@73ff64org.highwire.dtl.DTLVardef@1842158org.highwire.dtl.DTLVardef@1a92684org.highwire.dtl.DTLVardef@1fe596_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2023

The aryl hydrocarbon receptor regulates epidermal differentiation through transient activation of TFAP2A

The aryl hydrocarbon receptor (AHR) is an evolutionary conserved environmental sensor identified as indispensable regulator of epithelial homeostasis and barrier organ function. Molecular signaling cascade and target genes upon AHR activation and their contribution to cell and tissue function are however not fully understood. Multi-omics analyses using human skin keratinocytes revealed that, upon ligand activation, AHR binds open chromatin to induce expression of transcription factors (TFs), e.g., Transcription Factor AP-2 (TFAP2A), as a swift response to environmental stimuli. The terminal differentiation program including upregulation of barrier genes, filaggrin and keratins, was mediated by TFAP2A as a secondary response to AHR activation. The role of AHR-TFAP2A axis in controlling keratinocyte terminal differentiation for proper barrier formation was further confirmed using CRISPR/Cas9 in human epidermal equivalents. Overall, the study provides novel insights into the molecular mechanism behind AHR-mediated barrier function and potential novel targets for the treatment of skin barrier diseases.

cell biology↗

bioRxiv2023

Progesterone is an Inducement of Heritable Pulmonary Arterial Hypertension with BMPR2 Mutation

BackgroundBone morphogenetic protein type II receptor (BMPR2) gene mutation accounts for 80% of patients with heritable pulmonary artery hypertension (HPAH), and female mutation carriers have significantly higher penetrance rate than males. The inducement of HPAH penetrance and the mechanism of sex differential penetrance are still elusive. MethodsWe infected or transfected pulmonary artery smooth muscle cells (PASMCs) with shBMPR2 lentivirus or siBMPR2 to simulate the pathologic condition of BMPR2 heterozygous mutation and treated them with progesterone. The HPAH patient-derived induced pluripotent stem cells (iPSCs) were induced into vascular smooth muscle cells (VSMCs) to further verify the cellular phenotype. Wild-type flox+/- female mice and SM22-cre BMPR2 flox+/- female mice (CKO mice) were administered with 1-month progesterone, and their phenotype of PAH was evaluated by right heart catheterization and histopathological examination. ResultsProgesterone promoted the proliferation of PASMCs with BMPR2-knockdownby activating ERK pathway via progesterone receptor (PGR). Activated ERK not only upregulated the phosphorylation and elevation of cMYC, but also induced the transcription of endothelin (EDN1) by promoting the nuclear entry of c-JUN and combination on the its promoter region. Similar results were confirmed by iPSCs-VSMCs experiment. CKO mice developed PAH spontaneously and had increased expression of EDN1, which was further aggravated by exogenous progesterone. ConclusionsProgesterone might be an inducement of HPAH penetrance caused by BMPR2 mutation, accounting for sex differential penetrance.

molecular biology↗

bioRxiv2023

Pan-cancer analysis reveals tumor microbiome associations with host molecular aberrations

AbstractHost-microbiome interaction is known to play a pivotal role in the cancer ecosystem, yet the associations have not been systematically investigated at the pan-cancer and the multi-omics level. Here, we evaluated nearly 10,000 samples across 32 cancer types collected from The Cancer Genome Atlas (TCGA), to investigate the association between the tumor microbiome (taxa, n=1,630) and tumor microenvironment composition (cell types, n=20), epigenome (CpG island methylation, n=30,716), transcriptome (gene expression, n=10,216) and proteome (protein expression, n=193). We identified 836,738 candidate associations between the tumor microbiome and host molecular aberrations across multiple cancers. Besides cancer-specific associations, we also revealed recurrent pan-cancer associations between microbes (Lachnoclostridium, Flammeovirga, Terrabacter and Campylobacter) and immune cells, as well as between microbes (Collimonas and Sutterella) and fibroblasts, which were further validated by cell type estimations derived from pathological images and methylation data. We also identified several potential microbe and gene/protein expression associations mediated by DNA methylation using the sequential mediation analysis. Furthermore, our survival analysis demonstrated that tumor microbes may affect the patients overall survival and progression-free survival. Finally, a user-friendly web portal, Multi-Omics and Microbiome Associations in Cancer (MOMAC) was constructed for users to explore potential host-microbe interactions in cancer. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/536730v2_ufig1.gif" ALT="Figure 1"> View larger version (58K): org.highwire.dtl.DTLVardef@70f74eorg.highwire.dtl.DTLVardef@7c3078org.highwire.dtl.DTLVardef@152354dorg.highwire.dtl.DTLVardef@299282_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2023

Quorum-sensing gene regulates hormetic effects induced by sulfonamides in Comamonadaceae

Hormesis is a toxicological phenomenon whereby exposure to low-dose stress results in stimulation of various biological endpoints. Among these, the induction of cell proliferation by antibiotics is critical, but the underlying molecular mechanisms remain poorly understood. Here, we showed that sulfonyl-containing chemicals (e.g., sulfonamides) can induce cell-proliferation hormesis of Comamonas testosteroni. Investigation of the hormesis mechanism revealed that low-dose sulfonamides bind to the LuxR-type quorum sensing protein LuxR solo, thereby triggering the transcription of 3-ketoacyl-CoA thiolase, a key enzyme of the fatty acid {beta}-oxidation. This provides additional ATP, NADPH, and acetyl-CoA for purine and pyrimidine biosynthesis, allowing cells to synthesize sufficient nucleotides to support rapid cell growth. Our work reports on a previously unknown mechanism for the hormetic effect and highlights its generality in the Comamonadaceae family.

microbiology↗

bioRxiv2023

The Hsf1-sHsp cascade has pan-antiviral activity in mosquitoes

Aedes mosquitoes transmit pathogenic arthropod-borne (arbo) viruses, putting nearly half the worlds population at risk. Blocking virus replication in mosquitoes is a promising approach to prevent arbovirus transmission, the development of which requires in-depth knowledge of virus-host interactions and mosquito immunity. By integrating multi-omics data, we find that heat shock factor 1 (Hsf1) regulates eight small heat shock protein (sHsp) genes within one topologically associated domain in the mosquito genome. This Hsf1-sHsp cascade acts as an early response against chikungunya virus (CHIKV) infection and shows pan-antiviral activity in cell lines of three vector mosquitoes, Aedes aegypti, Aedes albopictus, and Anopheles gambiae. Our comprehensive in vitro data suggest that Hsf1 could serve as a promising target for the development of novel intervention strategies to limit arbovirus transmission by mosquitoes. Author summaryWith the unprecedented geographical expansion of Aedes mosquitoes, frequent resurgences of arbovirus epidemics have posed a significant health and economic burden. In light of this challenge, we have pursued an approach that seeks to find novel targets to block virus transmission at the mosquito stage. Through our multi-omics investigation, we have identified a new antiviral cascade, Hsf1-sHsp, that exhibits broad antiviral activity against alphaviruses and a flavivirus in cells of three vector mosquito species, Aedes aegypti, Aedes albopictus, and Anopheles gambiae. Given the pan-antiviral activity of the Hsf1-sHsp cascade, our findings have significant implications for understanding arbovirus-vector interactions and identifies Hsf1 as a putative target for novel approaches to prevent arbovirus transmission.

immunology↗

bioRxiv2023

Translational control by Trypanosoma brucei DRBD18 contributes to the maintenance of the procyclic state

Trypanosoma brucei occupies distinct niches throughout its life cycle, within both the mammalian and tsetse fly hosts. The immunological and biochemical complexity and variability of each of these environments require a reshaping of the protein landscape of the parasite both to evade surveillance and face changing metabolic demands. Whereas most well-studied organisms rely on transcriptional control as the main regulator of gene expression, post-transcriptional control mechanisms are particularly important in T. brucei, and these are often mediated by RNA-binding proteins. DRBD18 is a T. brucei RNA-binding protein that interacts with ribosomal proteins and translation factors. Here, we tested a role for DRBD18 in translational control. We show that DRBD18 depletion by RNA interference leads to altered polysomal profiles with a specific depletion of heavy polysomes. Ribosome profiling analysis reveals that 101 transcripts change in translational efficiency (TE) upon DRBD18 depletion: 41 exhibit decreased TE and 60 exhibit increased TE. A further 66 transcripts are buffered, i.e. changes in transcript abundance are compensated by changes in TE such that the total translational output is expected not to change. Proteomic analysis validates these data. In DRBD18-depleted cells, a cohort of transcripts that codes for procyclic form-specific proteins is translationally repressed while, conversely, transcripts that code for bloodstream form- and metacyclic form-specific proteins are translationally enhanced. These data suggest that DRBD18 contributes to the maintenance of the procyclic state through both positive and negative translational control of specific mRNAs.

microbiology↗

bioRxiv2023

Intravital microscopy of satellite cell dynamics and their interaction with myeloid cells during skeletal muscle regeneration

Skeletal muscle regeneration requires the highly coordinated cooperation of muscle satellite cells (MuSCs) with other cellular components. However, due to technical limitations, it remains unclear how MuSCs dynamically interact with non-myogenic cells, especially myeloid cells, in live animals. In this work, we developed a dual-laser multimodal nonlinear optical microscope platform to serve as an effective tool for studying the real-time interaction between MuSCs and non-myogenic cells during the early phase of muscle regeneration. Increased cell volume and mitochondrial mass, cell density, and myotube formation are indicative of MuSCs activation/growth, proliferation, and differentiation, respectively. Using 3D time-lapse imaging on live reporter mice containing both red fluorescence protein (RFP)-labeled macrophages and yellow fluorescence protein (YFP)-labeled MuSCs, and taking advantages of the autofluorescence of reduced nicotinamide adenine dinucleotide (NADH), we monitored the real-time spatiotemporal interaction between RFP+ macrophages/RFP- non-myogenic cells and YFP+ muscle stem/progenitor cells during the activation and the proliferation stages of regeneration. Our results indicated that their cell-cell contact was transient in nature. By inhibiting macrophage infiltration, we further showed that direct cell-cell contact between macrophages and MuSCs was not required for early activation of MuSCs before the proliferation stage. However, decreased macrophage infiltration impeded the proliferation and differentiation of MuSCs and also led to intramuscular fibrosis. Besides, neutrophil depletion in the CCR2 deficient mice did not delay the initial growth of MuSCs. These findings provide a new perspective on myeloid cells role during muscle regeneration.

cell biology↗