Adaptable haemodynamic endothelial cells for organogenesis and tumorigenesis.

Endothelial cells adopt tissue-specific characteristics to instruct organ development and regeneration1,2. This adaptability is lost in cultured adult endothelial cells, which do not vascularize tissues in an organotypic manner. Here, we show that transient reactivation of the embryonic-restricted ETS variant transcription factor 2 (ETV2)3 in mature human endothelial cells cultured in a serum-free three-dimensional matrix composed of a mixture of laminin, entactin and type-IV collagen (LEC matrix) 'resets' these endothelial cells to adaptable, vasculogenic cells, which form perfusable and plastic vascular plexi. Through chromatin remodelling, ETV2 induces tubulogenic pathways, including the activation of RAP1, which promotes the formation of durable lumens4,5. In three-dimensional matrices-which do not have the constraints of bioprinted scaffolds-the 'reset' vascular endothelial cells (R-VECs) self-assemble into stable, multilayered and branching vascular networks within scalable microfluidic chambers, which are capable of transporting human blood. In vivo, R-VECs implanted subcutaneously in mice self-organize into durable pericyte-coated vessels that functionally anastomose to the host circulation and exhibit long-lasting patterning, with no evidence of malformations or angiomas. R-VECs directly interact with cells within three-dimensional co-cultured organoids, removing the need for the restrictive synthetic semipermeable membranes that are required for organ-on-chip systems, therefore providing a physiological platform for vascularization, which we call 'Organ-On-VascularNet'. R-VECs enable perfusion of glucose-responsive insulin-secreting human pancreatic islets, vascularize decellularized rat intestines and arborize healthy or cancerous human colon organoids. Using single-cell RNA sequencing and epigenetic profiling, we demonstrate that R-VECs establish an adaptive vascular niche that differentially adjusts and conforms to organoids and tumoroids in a tissue-specific manner. Our Organ-On-VascularNet model will permit metabolic, immunological and physiochemical studies and screens to decipher the crosstalk between organotypic endothelial cells and parenchymal cells for identification of determinants of endothelial cell heterogeneity, and could lead to advances in therapeutic organ repair and tumour targeting.

miR-431 Promotes Metastasis of Pancreatic Neuroendocrine Tumors by Targeting DAB2 Interacting Protein, a Ras GTPase Activating Protein Tumor Suppressor.

The incidence of pancreatic neuroendocrine tumor (PNET) is increasing, and it presents with various clinical manifestations and an unfavorable survival rate. A better understanding of the drivers of PNET tumorigenesis is urgently needed. Distinct miRNA signatures have been identified for different stages of tumorigenesis in both human and mouse PNETs. The functions of these miRNAs are poorly understood. miR-431 is the most up-regulated miRNA in the metastatic signature. However, it is unknown whether miR-431 contributes to metastasis of PNETs. Herein, we show that miR-431 overexpression activates Ras/extracellular signal-regulated kinase (Erk) signaling and promotes epithelial-mesenchymal transition, migration/invasion in vitro, and metastasis in both xenograft and spontaneous mouse models of PNET. Treatment of PNET cells with Erk inhibitor or locked nucleic acids sequestering miR-431 inhibits invasion. Four target prediction modules and dual-luciferase reporter assays were used to identify potential mRNA targets of miR-431. A Ras GTPase activating protein tumor suppressor (RasGAP), DAB2 interacting protein (DAB2IP), was discovered as an miR-431 target. Overexpression of DAB2IP's rat homolog, but not its mutant defective in Ras GTPase activating protein activity, reverses miR-431's effect on promoting invasion, Erk phosphorylation, and epithelial-mesenchymal transition of PNETs. Taken together, miR-431 silences DAB2IP to active Ras/Erk and promote metastasis of PNETs. miR-431 may be targeted to manage metastatic PNETs.

RBP-J-Regulated miR-182 Promotes TNF-α-Induced Osteoclastogenesis.

Increased osteoclastogenesis is responsible for osteolysis, which is a severe consequence of inflammatory diseases associated with bone destruction, such as rheumatoid arthritis and periodontitis. The mechanisms that limit osteoclastogenesis under inflammatory conditions are largely unknown. We previously identified transcription factor RBP-J as a key negative regulator that restrains TNF-α-induced osteoclastogenesis and inflammatory bone resorption. In this study, we tested whether RBP-J suppresses inflammatory osteoclastogenesis by regulating the expression of microRNAs (miRNAs) important for this process. Using high-throughput sequencing of miRNAs, we obtained the first, to our knowledge, genome-wide profile of miRNA expression induced by TNF-α in mouse bone marrow-derived macrophages/osteoclast precursors during inflammatory osteoclastogenesis. Furthermore, we identified miR-182 as a novel miRNA that promotes inflammatory osteoclastogenesis driven by TNF-α and whose expression is suppressed by RBP-J. Downregulation of miR-182 dramatically suppressed the enhanced osteoclastogenesis program induced by TNF-α in RBP-J-deficient cells. Complementary loss- and gain-of-function approaches showed that miR-182 is a positive regulator of osteoclastogenic transcription factors NFATc1 and B lymphocyte-induced maturation protein-1. Moreover, we identified that direct miR-182 targets, Foxo3 and Maml1, play important inhibitory roles in TNF-α-mediated osteoclastogenesis. Thus, RBP-J-regulated miR-182 promotes TNF-α-induced osteoclastogenesis via inhibition of Foxo3 and Maml1. Suppression of miR-182 by RBP-J serves as an important mechanism that restrains TNF-α-induced osteoclastogenesis. Our results provide a novel miRNA-mediated mechanism by which RBP-J inhibits osteoclastogenesis and suggest that targeting of the newly described RBP-J-miR-182-Foxo3/Maml1 axis may represent an effective therapeutic approach to suppress inflammatory osteoclastogenesis and bone resorption.

The sex-specific transcriptome of the hermaphrodite sparid sharpsnout seabream (Diplodus puntazzo).

BACKGROUND: Teleosts are characterized by a remarkable breadth of sexual mechanisms including various forms of hermaphroditism. Sparidae is a fish family exhibiting gonochorism or hermaphroditism even in closely related species. The sparid Diplodus puntazzo (sharpsnout seabream), exhibits rudimentary hermaphroditism characterized by intersexual immature gonads but single-sex mature ones. Apart from the intriguing reproductive biology, it is economically important with a continuously growing aquaculture in the Mediterranean Sea, but limited available genetic resources. Our aim was to characterize the expressed transcriptome of gonads and brains through RNA-Sequencing and explore the properties of genes that exhibit sex-biased expression profiles. RESULTS: Through RNA-Sequencing we obtained an assembled transcriptome of 82,331 loci. The expression analysis uncovered remarkable differences between male and female gonads, while male and female brains were almost identical. Focused search for known targets of sex determination and differentiation in vertebrates built the sex-specific expression profile of sharpsnout seabream. Finally, a thorough genetic marker discovery pipeline led to the retrieval of 85,189 SNPs and 29,076 microsatellites enriching the available genetic markers for this species. CONCLUSIONS: We obtained a nearly complete source of transcriptomic sequence as well as marker information for sharpsnout seabream, laying the ground for understanding the complex process of sex differentiation of this economically valuable species. The genes involved include known candidates from other vertebrate species, suggesting a conservation of the toolkit between gonochorists and hermaphrodites.

The transcriptome of the baculovirus Autographa californica multiple nucleopolyhedrovirus in Trichoplusia ni cells.

Baculoviruses are important insect pathogens that have been developed as protein expression vectors in insect cells and as transduction vectors for mammalian cells. They have large double-stranded DNA genomes containing approximately 156 tightly spaced genes, and they present significant challenges for transcriptome analysis. In this study, we report the first comprehensive analysis of AcMNPV transcription over the course of infection in Trichoplusia ni cells, by a combination of strand-specific RNA sequencing (RNA-Seq) and deep sequencing of 5' capped transcription start sites and 3' polyadenylation sites. We identified four clusters of genes associated with distinctive patterns of mRNA accumulation through the AcMNPV infection cycle. A total of 218 transcription start sites (TSS) and 120 polyadenylation sites (PAS) were mapped. Only 29 TSS were associated with a canonical TATA box, and 14 initiated within or near the previously identified CAGT initiator motif. The majority of viral transcripts (126) initiated within the baculovirus late promoter motif (TAAG), and late transcripts initiated precisely at the second position of the motif. Analysis of 3' ends showed that 92 (77%) of the 3' PAS were located within 30 nucleotides (nt) downstream of a consensus termination signal (AAUAAA or AUUAAA). A conserved U-rich region was found approximately 2 to 10 nt downstream of the PAS for 58 transcripts. Twelve splicing events and an unexpectedly large number of antisense RNAs were identified, revealing new details of possible regulatory mechanisms controlling AcMNPV gene expression. Combined, these data provide an emerging global picture of the organization and regulation of AcMNPV transcription through the infection cycle.

Blockade of store-operated calcium entry by BTP2 preserves anti-inflammatory gene expression in human peripheral blood mononuclear cells.

Store-operated calcium entry (SOCE) is essential for cellular signaling. Earlier studies of the pyrazole derivative BTP2, an efficient inhibitor SOCE, identified that SOCE blockade suppresses proinflammatory gene expression. The impact of SOCE blockade on gene expression at the whole transcriptome level, however, is unknown. To fill this gap, we performed RNA sequencing (RNA-seq) and investigated at the whole transcriptome level the effect of BTP2 on gene expression in human peripheral blood mononuclear cells signaled with phytohemagglutinin. Our global gene expression analysis identified that SOCE blockade spares activation-induced expression of anti-inflammatory genes (e.g., IL10, TGFB1, FOXP3, and CTLA4) whereas the induced expression of proinflammatory genes such as IFNG and cytopathic genes such as GZMB are inhibited. We validated the differential expression of immunoregulatory genes identified by RNA-seq using preamplification-enhanced RT-qPCR assays. Because IL-2/IL2RA interaction is essential for T cell clonal expansion, we investigated and confirmed that BTP2 inhibits IL2RA expression at the protein level using multiparameter flow cytometry. Our elucidation that SOCE blockade spares activation-induced expression of anti-inflammatory genes while blocking pro-inflammatory gene expression suggests that SOCE blockers may represent a novel class of immunoregulatory drugs of value for treating autoimmune disease states and organ transplantation.

RNA-sequencing of Human Kidney Allografts and Delineation of T-Cell Genes, Gene Sets, and Pathways Associated With Acute T Cell-mediated Rejection.

BACKGROUND: Delineation of T-cell genes, gene sets, pathways, and T-cell subtypes associated with acute T cell-mediated rejection (TCMR) may improve its management. METHODS: We performed bulk RNA-sequencing of 34 kidney allograft biopsies (16 Banff TCMR and 18 no rejection [NR] biopsies) from 34 adult recipients of human kidneys. Computational analysis was performed to determine the differential intragraft expression of T-cell genes at the level of single-gene, gene set, and pathways. RESULTS: T-cell signaling pathway gene sets for plenary T-cell activation were overrepresented in TCMR biopsies compared with NR biopsies. Heightened expression of T-cell signaling genes was validated using external TCMR biopsies. Pro- and anti-inflammatory immune gene sets were enriched, and metabolism gene sets were depleted in TCMR biopsies compared with NR biopsies. Gene signatures of regulatory T cells, Th1 cells, Th2 cells, Th17 cells, T follicular helper cells, CD4 tissue-resident memory T cells, and CD8 tissue-resident memory T cells were enriched in TCMR biopsies compared with NR biopsies. T-cell exhaustion and anergy were also molecular attributes of TCMR. Gene sets associated with antigen processing and presentation, and leukocyte transendothelial migration were overexpressed in TCMR biopsies compared with NR biopsies. Cellular deconvolution of graft infiltrating cells by gene expression patterns identified CD8 T cell to be the most abundant T-cell subtype infiltrating the allograft during TCMR. CONCLUSIONS: Our delineation of intragraft T-cell gene expression patterns, in addition to yielding new biological insights, may help prioritize T-cell genes and T-cell subtypes for therapeutic targeting.

Human vascularized macrophage-islet organoids to model immune-mediated pancreatic ß cell pyroptosis upon viral infection.

There is a paucity of human models to study immune-mediated host damage. Here, we utilized the GeoMx spatial multi-omics platform to analyze immune cell changes in COVID-19 pancreatic autopsy samples, revealing an accumulation of proinflammatory macrophages. Single-cell RNA sequencing (scRNA-seq) analysis of human islets exposed to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or coxsackievirus B4 (CVB4) viruses identified activation of proinflammatory macrophages and ß cell pyroptosis. To distinguish viral versus proinflammatory-macrophage-mediated ß cell pyroptosis, we developed human pluripotent stem cell (hPSC)-derived vascularized macrophage-islet (VMI) organoids. VMI organoids exhibited enhanced marker expression and function in both ß cells and endothelial cells compared with separately cultured cells. Notably, proinflammatory macrophages within VMI organoids induced ß cell pyroptosis. Mechanistic investigations highlighted TNFSF12-TNFRSF12A involvement in proinflammatory-macrophage-mediated ß cell pyroptosis. This study established hPSC-derived VMI organoids as a valuable tool for studying immune-cell-mediated host damage and uncovered the mechanism of ß cell damage during viral exposure.

Bcl-xL is translocated to the nucleus via CtBP2 to epigenetically promote metastasis.

Nuclear Bcl-xL is found to promote cancer metastasis independently of its mitochondria-based anti-apoptotic activity. How Bcl-xL is translocated into the nucleus and how nuclear Bcl-xL regulates histone H3 trimethyl Lys4 (H3K4me3) modification have yet to be understood. Here, we report that C-terminal Binding Protein 2 (CtBP2) binds to Bcl-xL via its N-terminus and translocates Bcl-xL into the nucleus. Knockdown of CtBP2 by shRNA decreases the nuclear portion of Bcl-xL and reverses Bcl-xL-induced invasion and metastasis in mouse models. Furthermore, knockout of CtBP2 not only reduces the nuclear portion of Bcl-xL but also suppresses Bcl-xL transcription. The binding between Bcl-xL and CtBP2 is required for their interaction with MLL1, a histone H3K4 methyltransferase. Pharmacologic inhibition of the MLL1 enzymatic activity reverses Bcl-xL-induced H3K4me3 and TGFß mRNA upregulation, as well as invasion. Moreover, the cleavage under targets and release using nuclease (CUT&RUN) assay coupled with next-generation sequencing reveals that H3K4me3 modifications are particularly enriched in the promotor regions of genes encoding TGFß and its signaling pathway members in cancer cells overexpressing Bcl-xL. Altogether, the metastatic function of Bcl-xL is mediated by its interaction with CtBP2 and MLL1 and this study offers new therapeutic strategies to treat Bcl-xL-overexpressing cancer.

Human Vascularized Macrophage-Islet Organoids to Model Immune-Mediated Pancreatic ß cell Pyroptosis upon Viral Infection.

There is a paucity of human models to study immune-mediated host damage. Here, we utilized the GeoMx spatial multi-omics platform to analyze immune cell changes in COVID-19 pancreatic autopsy samples, revealing an accumulation of proinflammatory macrophages. Single cell RNA-seq analysis of human islets exposed to SARS-CoV-2 or Coxsackievirus B4 (CVB4) viruses identified activation of proinflammatory macrophages and ß cell pyroptosis. To distinguish viral versus proinflammatory macrophage-mediated ß cell pyroptosis, we developed human pluripotent stem cell (hPSC)-derived vascularized macrophage-islet (VMI) organoids. VMI organoids exhibited enhanced marker expression and function in both ß cells and endothelial cells compared to separately cultured cells. Notably, proinflammatory macrophages within VMI organoids induced ß cell pyroptosis. Mechanistic investigations highlighted TNFSF12-TNFRSF12A involvement in proinflammatory macrophage-mediated ß cell pyroptosis. This study established hPSC-derived VMI organoids as a valuable tool for studying immune cell-mediated host damage and uncovered mechanism of ß cell damage during viral exposure.

Mutations in FLVCR1 cause posterior column ataxia and retinitis pigmentosa.

The study of inherited retinal diseases has advanced our knowledge of the cellular and molecular mechanisms involved in sensory neural signaling. Dysfunction of two specific sensory modalities, vision and proprioception, characterizes the phenotype of the rare, autosomal-recessive disorder posterior column ataxia and retinitis pigmentosa (PCARP). Using targeted DNA capture and high-throughput sequencing, we analyzed the entire 4.2 Mb candidate sequence on chromosome 1q32 to find the gene mutated in PCARP in a single family. Employing comprehensive bioinformatic analysis and filtering, we identified a single-nucleotide coding variant in the feline leukemia virus subgroup C cellular receptor 1 (FLVCR1), a gene encoding a heme-transporter protein. Sanger sequencing confirmed the FLVCR1 mutation in this family and identified different homozygous missense mutations located within the protein's transmembrane channel segment in two other unrelated families with PCARP. To determine whether the selective pathologic features of PCARP correlated with FLVCR1 expression, we examined wild-type mouse Flvcr1 mRNA levels in the posterior column of the spinal cord and the retina via quantitative real-time reverse-transcriptase PCR. The Flvcr1 mRNA levels were most abundant in the retina, followed by the posterior column of the spinal cord and other brain regions. These results suggest that aberrant FLVCR1 causes a selective degeneration of a subpopulation of neurons in the retina and the posterior columns of the spinal cord via dysregulation of heme or iron homeostasis. This finding broadens the molecular basis of sensory neural signaling to include common mechanisms that involve proprioception and vision.

Selective modulation of gene expression in activated normal human peripheral blood mononuclear cells by store-operated calcium entry blocker BTP2.

Calcium is a critical signaling molecule in many cell types including immune cells. The calcium-release activated calcium channels (CRAC) responsible for store-operated calcium entry (SOCE) in immune cells are gated by STIM family members functioning as sensors of Ca2+ store content in the endoplasmic reticulum. We investigated the effect of SOCE blocker BTP2 on human peripheral blood mononuclear cells (PBMC) stimulated with the mitogen phytohemagglutinin (PHA). We performed RNA sequencing (RNA-seq) to query gene expression at the whole transcriptome level and identified genes differentially expressed between PBMC activated with PHA and PBMC activated with PHA in the presence of BTP2. Among the differentially expressed genes, we prioritized genes encoding immunoregulatory proteins for validation using preamplification enhanced real time quantitative PCR assays. We performed multiparameter flow cytometry and validated by single cell analysis that BTP2 inhibits cell surface expression CD25 at the protein level. BTP2 reduced significantly PHA-induced increase in the abundance of mRNAs encoding proinflammatory proteins. Surprisingly, BTP2 did not reduce significantly PHA-induced increase in the abundance of mRNAs encoding anti-inflammatory proteins. Collectively, the molecular signature elicited by BTP2 in activated normal human PBMC appears to be tipped towards tolerance and away from inflammation.

Vascular oxidative stress causes neutrophil arrest in brain capillaries, leading to decreased cerebral blood flow and contributing to memory impairment in a mouse model of Alzheimer’s disease.

INTRODUCTION: In this study, we explore the role of oxidative stress produced by NOX2-containing NADPH oxidase as a molecular mechanism causing capillary stalling and cerebral blood flow deficits in the APP/PS1 mouse model of AD. METHODS: We inhibited NOX2 in APP/PS1 mice by administering a 10 mg/kg dose of the peptide inhibitor gp91-ds-tat i.p., for two weeks. We used in vivo two-photon imaging to measure capillary stalling, penetrating arteriole flow, and vascular inflammation. We also characterized short-term memory function and gene expression changes in cerebral microvessels. RESULTS: We found that after NOX2 inhibition capillary stalling, as well as parenchymal and vascular inflammation, were significantly reduced. In addition, we found a significant increase in penetrating arteriole flow, followed by an improvement in short-term memory, and downregulation of inflammatory gene expression pathways. DISCUSSION: Oxidative stress is a major mechanism leading to microvascular dysfunction in AD, and represents an important therapeutic target.

Bcl-xL is translocated to the nucleus via CtBP2 to epigenetically promote metastasis.

Besides its mitochondria-based anti-apoptotic role, Bcl-xL also travels to the nucleus to promote cancer metastasis by upregulating global histone H3 trimethyl Lys4 (H3K4me3) and TGFß transcription. How Bcl-xL is translocated into the nucleus and how nuclear Bcl-xL regulates H3K4me3 modification are not understood. Here, we report that C-terminal Binding Protein 2 (CtBP2) binds Bcl-xL via its N-terminus and translocates Bcl-xL into the nucleus. Knockdown of CtBP2 by shRNA decreases the nuclear portion of Bcl-xL and reverses Bcl-xL-induced cell migration and metastasis in mouse models. Furthermore, knockout of CtBP2 suppresses Bcl-xL transcription. The binding between Bcl-xL and CtBP2 is required for their interaction with MLL1, a histone H3K4 methyltransferase. Pharmacologic inhibition of MLL1 enzymatic activity reverses Bcl-xL-induced H3K4me3 and TGFß mRNA upregulation as well as cell invasion. Moreover, cleavage under targets and release using nuclease (CUT&RUN) coupled with next generation sequencing reveals that H3K4me3 modifications are particularly enriched in the promotor region of genes encoding TGFß and its signaling pathway in the cancer cells overexpressing Bcl-xL. Altogether, the metastatic function of Bcl-xL is mediated by its interaction with CtBP2 and MLL1.

Transcriptional Activation of Regenerative Hematopoiesis via Vascular Niche Sensing.

Transition between activation and quiescence programs in hematopoietic stem and progenitor cells (HSC/HSPCs) is perceived to be governed intrinsically and by microenvironmental co-adaptation. However, HSC programs dictating both transition and adaptability, remain poorly defined. Single cell multiome analysis divulging differential transcriptional activity between distinct HSPC states, indicated for the exclusive absence of Fli-1 motif from quiescent HSCs. We reveal that Fli-1 activity is essential for HSCs during regenerative hematopoiesis. Fli-1 directs activation programs while manipulating cellular sensory and output machineries, enabling HSPCs co-adoptability with a stimulated vascular niche. During regenerative conditions, Fli-1 presets and enables propagation of niche-derived Notch1 signaling. Constitutively induced Notch1 signaling is sufficient to recuperate functional HSC impairments in the absence of Fli-1. Applying FLI-1 modified-mRNA transduction into lethargic adult human mobilized HSPCs, enables their vigorous niche-mediated expansion along with superior engraftment capacities. Thus, decryption of stem cell activation programs offers valuable insights for immune regenerative medicine.

Molecular Evolution of Classic Hodgkin Lymphoma Revealed Through Whole-Genome Sequencing of Hodgkin and Reed Sternberg Cells.

The rarity of malignant Hodgkin and Reed Sternberg (HRS) cells in classic Hodgkin lymphoma (cHL) limits the ability to study the genomics of cHL. To circumvent this, our group has previously optimized fluorescence-activated cell sorting to purify HRS cells. Using this approach, we now report the whole-genome sequencing landscape of HRS cells and reconstruct the chronology and likely etiology of pathogenic events leading to cHL. We identified alterations in driver genes not previously described in cHL, APOBEC mutational activity, and the presence of complex structural variants including chromothripsis. We found that high ploidy in cHL is often acquired through multiple, independent chromosomal gains events including whole-genome duplication. Evolutionary timing analyses revealed that structural variants enriched for RAG motifs, driver mutations in B2M, BCL7A, GNA13, and PTPN1, and the onset of AID-driven mutagenesis usually preceded large chromosomal gains. This study provides a temporal reconstruction of cHL pathogenesis. SIGNIFICANCE: Previous studies in cHL were limited to coding sequences and therefore not able to comprehensively decipher the tumor complexity. Here, leveraging cHL whole-genome characterization, we identify driver events and reconstruct the tumor evolution, finding that structural variants, driver mutations, and AID mutagenesis precede chromosomal gains. This article is highlighted in the In This Issue feature, p. 171.

Epsilon toxin-producing Clostridium perfringens colonize the multiple sclerosis gut microbiome overcoming CNS immune privilege.

Multiple sclerosis (MS) is a complex disease of the CNS thought to require an environmental trigger. Gut dysbiosis is common in MS, but specific causative species are unknown. To address this knowledge gap, we used sensitive and quantitative PCR detection to show that people with MS were more likely to harbor and show a greater abundance of epsilon toxin-producing (ETX-producing) strains of C. perfringens within their gut microbiomes compared with individuals who are healthy controls (HCs). Isolates derived from patients with MS produced functional ETX and had a genetic architecture typical of highly conjugative plasmids. In the active immunization model of experimental autoimmune encephalomyelitis (EAE), where pertussis toxin (PTX) is used to overcome CNS immune privilege, ETX can substitute for PTX. In contrast to PTX-induced EAE, where inflammatory demyelination is largely restricted to the spinal cord, ETX-induced EAE caused demyelination in the corpus callosum, thalamus, cerebellum, brainstem, and spinal cord, more akin to the neuroanatomical lesion distribution seen in MS. CNS endothelial cell transcriptional profiles revealed ETX-induced genes that are known to play a role in overcoming CNS immune privilege. Together, these findings suggest that ETX-producing C. perfringens strains are biologically plausible pathogens in MS that trigger inflammatory demyelination in the context of circulating myelin autoreactive lymphocytes.

Allele-informed copy number evaluation of plasma DNA samples from metastatic prostate cancer patients: the PCF_SELECT consortium assay.

Sequencing of cell-free DNA (cfDNA) in cancer patients' plasma offers a minimally-invasive solution to detect tumor cell genomic alterations to aid real-time clinical decision-making. The reliability of copy number detection decreases at lower cfDNA tumor fractions, limiting utility at earlier stages of the disease. To test a novel strategy for detection of allelic imbalance, we developed a prostate cancer bespoke assay, PCF_SELECT, that includes an innovative sequencing panel covering ∼25 000 high minor allele frequency SNPs and tailored analytical solutions to enable allele-informed evaluation. First, we assessed it on plasma samples from 50 advanced prostate cancer patients. We then confirmed improved detection of genomic alterations in samples with <10% tumor fractions when compared against an independent assay. Finally, we applied PCF_SELECT to serial plasma samples intensively collected from three patients previously characterized as harboring alterations involving DNA repair genes and consequently offered PARP inhibition. We identified more extensive pan-genome allelic imbalance than previously recognized in prostate cancer. We confirmed high sensitivity detection of BRCA2 allelic imbalance with decreasing tumor fractions resultant from treatment and identified complex ATM genomic states that may be incongruent with protein losses. Overall, we present a framework for sensitive detection of allele-specific copy number changes in cfDNA.

Low-dose carbon monoxide suppresses metastatic progression of disseminated cancer cells.

Low-dose carbon monoxide (CO) is under investigation in clinical trials to treat non-cancerous diseases and has an excellent safety profile. Due to early detection and cancer awareness, an increasing number of cancer patients are diagnosed at early stages, when potentially curative surgical resection can be done. However, many patients ultimately experience recurrence. Here, we evaluate the therapeutic effect of CO on metastatic cancer progression. We show that 250 ppm CO inhibits the migration of multiple types of cancer cell lines, including breast, pancreatic, colon, prostate, liver, and lung cancer and reduces the ability to adhere to fibronectin. We demonstrate that in mouse models, 250 ppm inhaled CO inhibits lung metastasis of breast cancer and liver metastasis of pancreatic cancer. Moreover, low-dose CO suppresses recurrence and increases survival after surgical removal of primary pancreatic cancer in mice. Mechanistically, low-dose CO blocks transcription of heme importers, leading to diminished intracellular heme levels and a heme-regulated enzyme, cytochrome P4501B1 (CYP1B1). Either supplementing heme or overexpressing CYP1B1 reverses the anti-migration effect of low-dose CO. Taken together, low-dose CO therapy inhibits cell migration, reduces adhesion to fibronectin, prevents disseminated cancer cells from expanding into gross metastases, and improves survival in pre-clinical mouse models of metastasis.

A human iPSC-array-based GWAS identifies a virus susceptibility locus in the NDUFA4 gene and functional variants.

Population-based studies to identify disease-associated risk alleles typically require samples from a large number of individuals. Here, we report a human-induced pluripotent stem cell (hiPSC)-based screening strategy to link human genetics with viral infectivity. A genome-wide association study (GWAS) identified a cluster of single-nucleotide polymorphisms (SNPs) in a cis-regulatory region of the NDUFA4 gene, which was associated with susceptibility to Zika virus (ZIKV) infection. Loss of NDUFA4 led to decreased sensitivity to ZIKV, dengue virus, and SARS-CoV-2 infection. Isogenic hiPSC lines carrying non-risk alleles of SNPs or deletion of the cis-regulatory region lower sensitivity to viral infection. Mechanistic studies indicated that loss/reduction of NDUFA4 causes mitochondrial stress, which leads to the leakage of mtDNA and thereby upregulation of type I interferon signaling. This study provides proof-of-principle for the application of iPSC arrays in GWAS and identifies NDUFA4 as a previously unknown susceptibility locus for viral infection.