Browsing by Author "LeBleu, Valerie S."

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    Circulating ACE2-expressing extracellular vesicles block broad strains of SARS-CoV-2
    (Springer Nature, 2022) El-Shennawy, Lamiaa; Hoffmann, Andrew D.; Dashzeveg, Nurmaa Khund; McAndrews, Kathleen M.; Mehl, Paul J.; Cornish, Daphne; Yu, Zihao; Tokars, Valerie L.; Nicolaescu, Vlad; Tomatsidou, Anastasia; Mao, Chengsheng; Felicelli, Christopher J.; Tsai, Chia-Feng; Ostiguin, Carolina; Jia, Yuzhi; Li, Lin; Furlong, Kevin; Wysocki, Jan; Luo, Xin; Ruivo, Carolina F.; Batlle, Daniel; Hope, Thomas J.; Shen, Yang; Chae, Young Kwang; Zhang, Hui; LeBleu, Valerie S.; Shi, Tujin; Swaminathan, Suchitra; Luo, Yuan; Missiakas, Dominique; Randall, Glenn C.; Demonbreun, Alexis R.; Ison, Michael G.; Kalluri, Raghu; Fang, Deyu; Liu, Huiping
    The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused the pandemic of the coronavirus induced disease 2019 (COVID-19) with evolving variants of concern. It remains urgent to identify novel approaches against broad strains of SARS-CoV-2, which infect host cells via the entry receptor angiotensin-converting enzyme 2 (ACE2). Herein, we report an increase in circulating extracellular vesicles (EVs) that express ACE2 (evACE2) in plasma of COVID-19 patients, which levels are associated with severe pathogenesis. Importantly, evACE2 isolated from human plasma or cells neutralizes SARS-CoV-2 infection by competing with cellular ACE2. Compared to vesicle-free recombinant human ACE2 (rhACE2), evACE2 shows a 135-fold higher potency in blocking the binding of the viral spike protein RBD, and a 60- to 80-fold higher efficacy in preventing infections by both pseudotyped and authentic SARS-CoV-2. Consistently, evACE2 protects the hACE2 transgenic mice from SARS-CoV-2-induced lung injury and mortality. Furthermore, evACE2 inhibits the infection of SARS-CoV-2 variants (α, β, and δ) with equal or higher potency than for the wildtype strain, supporting a broad-spectrum antiviral mechanism of evACE2 for therapeutic development to block the infection of existing and future coronaviruses that use the ACE2 receptor.
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    Genetic reprogramming with stem cells regenerates glomerular epithelial podocytes in Alport syndrome
    (Embo Press, 2024) LeBleu, Valerie S.; Kanasaki, Keizo; Lovisa, Sara; Alge, Joseph L.; Kim, Jiha; Chen, Yang; Teng, Yingqi; Gerami-Naini, Behzad; Sugimoto, Hikaru; Kato, Noritoshi; Revuelta, Ignacio; Grau, Nicole; Sleeman, Jonathan P.; Taduri, Gangadhar; Kizu, Akane; Rafii, Shahin; Hochedlinger, Konrad; Quaggin, Susan E.; Kalluri, Raghu
    Glomerular filtration relies on the type IV collagen (ColIV) network of the glomerular basement membrane, namely, in the triple helical molecules containing the α3, α4, and α5 chains of ColIV. Loss of function mutations in the genes encoding these chains (Col4a3, Col4a4, and Col4a5) is associated with the loss of renal function observed in Alport syndrome (AS). Precise understanding of the cellular basis for the patho-mechanism remains unknown and a specific therapy for this disease does not currently exist. Here, we generated a novel allele for the conditional deletion of Col4a3 in different glomerular cell types in mice. We found that podocytes specifically generate α3 chains in the developing glomerular basement membrane, and that its absence is sufficient to impair glomerular filtration as seen in AS. Next, we show that horizontal gene transfer, enhanced by TGFβ1 and using allogenic bone marrow–derived mesenchymal stem cells and induced pluripotent stem cells, rescues Col4a3 expression and revive kidney function in Col4a3-deficient AS mice. Our proof-of-concept study supports that horizontal gene transfer such as cell fusion enables cell-based therapy in Alport syndrome.
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    Heterogeneous antibodies against SARS-CoV-2 spike receptor binding domain and nucleocapsid with implications for COVID-19 immunity
    (American Society for Clinical Investigation, 2020) McAndrews, Kathleen M.; Dowlatshahi, Dara P.; Dai, Jianli; Becker, Lisa M.; Hensel, Janine; Snowden, Laura M.; Leveille, Jennifer M.; Brunner, Michael R.; Holden, Kylie W.; Hopkins, Nikolas S.; Harris, Alexandria M.; Kumpati, Jerusha; Whitt, Michael A.; Lee, J. Jack; Ostrosky-Zeichner, Luis L.; Papanna, Ramesha; LeBleu, Valerie S.; Allison, James P.; Kalluri, Raghu
    Evaluation of potential immunity against the novel severe acute respiratory syndrome (SARS) coronavirus that emerged in 2019 (SARS-CoV-2) is essential for health, as well as social and economic recovery. Generation of antibody response to SARS-CoV-2 (seroconversion) may inform on acquired immunity from prior exposure, and antibodies against the SARS-CoV-2 spike protein receptor binding domain (S-RBD) are speculated to neutralize virus infection. Some serology assays rely solely on SARS-CoV-2 nucleocapsid protein (N-protein) as the antibody detection antigen; however, whether such immune responses correlate with S-RBD response and COVID-19 immunity remains unknown. Here, we generated a quantitative serological ELISA using recombinant S-RBD and N-protein for the detection of circulating antibodies in 138 serial serum samples from 30 reverse transcription PCR–confirmed, SARS-CoV-2–hospitalized patients, as well as 464 healthy and non–COVID-19 serum samples that were collected between June 2017 and June 2020. Quantitative detection of IgG antibodies against the 2 different viral proteins showed a moderate correlation. Antibodies against N-protein were detected at a rate of 3.6% in healthy and non–COVID-19 sera collected during the pandemic in 2020, whereas 1.9% of these sera were positive for S-RBD. Approximately 86% of individuals positive for S-RBD–binding antibodies exhibited neutralizing capacity, but only 74% of N-protein–positive individuals exhibited neutralizing capacity. Collectively, our studies show that detection of N-protein–binding antibodies does not always correlate with presence of S-RBD–neutralizing antibodies and caution against the extensive use of N-protein–based serology testing for determination of potential COVID-19 immunity.
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    Identification of unique α4 chain structure and conserved antiangiogenic activity of α3NC1 type IV collagen in zebrafish
    (Wiley, 2023) LeBleu, Valerie S.; Dai, Jianli; Tsutakawa, Susan; MacDonald, Brian A.; Alge, Joseph L.; Sund, Malin; Xie, Liang; Sugimoto, Hikaru; Tainer, John; Zon, Leonard I.; Kalluri, Raghu
    Background Type IV collagen is an abundant component of basement membranes in all multicellular species and is essential for the extracellular scaffold supporting tissue architecture and function. Lower organisms typically have two type IV collagen genes, encoding α1 and α2 chains, in contrast with the six genes in humans, encoding α1–α6 chains. The α chains assemble into trimeric protomers, the building blocks of the type IV collagen network. The detailed evolutionary conservation of type IV collagen network remains to be studied. Results We report on the molecular evolution of type IV collagen genes. The zebrafish α4 non-collagenous (NC1) domain, in contrast with its human ortholog, contains an additional cysteine residue and lacks the M93 and K211 residues involved in sulfilimine bond formation between adjacent protomers. This may alter α4 chain interactions with other α chains, as supported by temporal and anatomic expression patterns of collagen IV chains during the zebrafish development. Despite the divergence between zebrafish and human α3 NC1 domain (endogenous angiogenesis inhibitor, Tumstatin), the zebrafish α3 NC1 domain exhibits conserved antiangiogenic activity in human endothelial cells. Conclusions Our work supports type IV collagen is largely conserved between zebrafish and humans, with a possible difference involving the α4 chain.
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    Protection against SARS-CoV-2 by BCG vaccination is not supported by epidemiological analyses
    (Springer Nature, 2020) Hensel, Janine; McAndrews, Kathleen M.; McGrail, Daniel J.; Dowlatshahi, Dara P.; LeBleu, Valerie S.; Kalluri, Raghu
    The Bacillus Calmette-Guerin (BCG) vaccine provides protection against tuberculosis (TB), and is thought to provide protection against non-TB infectious diseases. BCG vaccination has recently been proposed as a strategy to prevent infection with SARS-CoV-2 (CoV-2) to combat the COVID-19 outbreak, supported by its potential to boost innate immunity and initial epidemiological analyses which observed reduced severity of COVID-19 in countries with universal BCG vaccination policies. Seventeen clinical trials are currently registered to inform on the benefits of BCG vaccinations upon exposure to CoV-2. Numerous epidemiological analyses showed a correlation between incidence of COVID-19 and BCG vaccination policies. These studies were not systematically corrected for confounding variables. We observed that after correction for confounding variables, most notably testing rates, there was no association between BCG vaccination policy and COVD-19 spread rate or percent mortality. Moreover, we found variables describing co-morbidities, including cardiovascular death rate and smoking prevalence, were significantly associated COVID-19 spread rate and percent mortality, respectively. While reporting biases may confound our observations, our epidemiological findings do not provide evidence to correlate overall BCG vaccination policy with the spread of CoV-2 and its associated mortality.
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    Unique somatic variants in DNA from urine exosomes of individuals with bladder cancer
    (Elsevier, 2021) Zhou, Xunian; Kurywchak, Paul; Wolf-Dennen, Kerri; Che, Sara P. Y.; Sulakhe, Dinanath; D’Souza, Mark; Xie, Bingqing; Maltsev, Natalia; Gilliam, T. Conrad; Wu, Chia-Chin; McAndrews, Kathleen M.; LeBleu, Valerie S.; McConkey, David J.; Volpert, Olga V.; Pretzsch, Shanna M.; Czerniak, Bogdan A.; Dinney, Colin P.; Kalluri, Raghu
    Bladder cancer (BC), a heterogeneous disease characterized by high recurrence rates, is diagnosed and monitored by cystoscopy. Accurate clinical staging based on biopsy remains a challenge, and additional, objective diagnostic tools are needed urgently. We used exosomal DNA (exoDNA) as an analyte to examine cancer-associated mutations and compared the diagnostic utility of exoDNA from urine and serum of individuals with BC. In contrast to urine exosomes from healthy individuals, urine exosomes from individuals with BC contained significant amounts of DNA. Whole-exome sequencing of DNA from matched urine and serum exosomes, bladder tumors, and normal tissue (peripheral blood mononuclear cells) identified exonic and 3′ UTR variants in frequently mutated genes in BC, detectable in urine exoDNA and matched tumor samples. Further analyses identified somatic variants in driver genes, unique to urine exoDNA, possibly because of the inherent intra-tumoral heterogeneity of BC, which is not fully represented in random small biopsies. Multiple variants were also found in untranslated portions of the genome, such as microRNA (miRNA)-binding regions of the KRAS gene. Gene network analyses revealed that exoDNA is associated with cancer, inflammation, and immunity in BC exosomes. Our findings show utility of exoDNA as an objective, non-invasive strategy to identify novel biomarkers and targets for BC.