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Found 37003 matches. Displaying 51-60
Dam KMA, Barnes CO, Gristick HB, Schoofs T, Gnanapragasam PNP, Nussenzweig MC, Bjorkman PJ
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HIV-1 CD4-binding site germline antibody-Env structures inform vaccine design

NATURE COMMUNICATIONS 2022 OCT 17; 13(1):? Article 6123
BG24, a VRC01-class broadly neutralizing antibody (bNAb) against HIV-1 Env with relatively few somatic hypermutations (SHMs), represents a promising target for vaccine strategies to elicit CD4-binding site (CD4bs) bNAbs. To understand how SHMs correlate with BG24 neutralization of HIV-1, we report 4.1 angstrom and 3.4 angstrom single-particle cryo-EM structures of two inferred germline (iGL) BG24 precursors complexed with engineered Env-based immunogens lacking CD4bs N-glycans. Structures reveal critical Env contacts by BG24(iGL) and identify antibody light chain structural features that impede Env recognition. In addition, biochemical data and cryo-EM structures of BG24(iGL) variants bound to Envs with CD4bs glycans present provide insights into N-glycan accommodation, including structural modes of light chain adaptations in the presence of the N276(gp120) glycan. Together, these findings reveal Env regions critical for germline antibody recognition and potential sites to alter in immunogen design.
An U, Shenhav L, Olson CA, Hsiao EY, Halperin E, Sankararaman S
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STENSL: Microbial Source Tracking with ENvironment SeLection

MSYSTEMS 2022 OCT 26; 7(5):?
Microbial source tracking analysis has emerged as a widespread technique for characterizing the properties of complex microbial communities. However, this analysis is currently limited to source environments sampled in a specific study. In order to expand the scope beyond one single study and allow the exploration of source environments using large databases and repositories, such as the Earth Microbiome Project, a source selection procedure is required. Such a procedure will allow differentiating between contributing environments and nuisance ones when the number of potential sources considered is high. Here, we introduce STENSL (microbial Source Tracking with ENvironment SeLection), a machine learning method that extends common microbial source tracking analysis by performing an unsupervised source selection and enabling sparse identification of latent source environments. By incorporating sparsity into the estimation of potential source environments, STENSL improves the accuracy of true source contribution, while significantly reducing the noise introduced by noncontributing ones. We therefore anticipate that source selection will augment microbial source tracking analyses, enabling exploration of multiple source environments from publicly available repositories while maintaining high accuracy of the statistical inference. IMPORTANCE Microbial source tracking is a powerful tool to characterize the properties of complex microbial communities. However, this analysis is currently limited to source environments sampled in a specific study. In many applications there is a clear need to consider source selection over a large array of microbial environments, external to the study. To this end, we developed STENSL (microbial Source Tracking with ENvironment SeLection), an expectation-maximization algorithm with sparsity that enables the identification of contributing sources among a large set of potential microbial environments. With the unprecedented expansion of microbiome data repositories such as the Earth Microbiome Project, recording over 200,000 samples from more than 50 types of categorized environments, STENSL takes the first steps in performing automated source exploration and selection. STENSL is significantly more accurate in identifying the contributing sources as well as the unknown source, even when considering hundreds of potential source environments, settings in which state-of-the-art microbial source tracking methods add considerable error.
Tabansky I, Tanaka AJ, Wang JY, Zhang GL, Dujmovic I, Mader S, Jeganathan V, DeAngelis T, Funaro M, Harel A, Messina M, Shabbir M, Nursey V, DeGouvia W, Laurent M, Blitz K, Jindra P, Gudesblatt M, Regeneron Genetics Ctr, King A, Drulovic J, Yunis E, Brusic V, Shen YF, Keskin DB, Najjar S, Stern JNH
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Rare variants and HLA haplotypes associated in patients with neuromyelitis optica spectrum disorders

FRONTIERS IN IMMUNOLOGY 2022 OCT 4; 13(?):? Article 900605
Neuromyelitis optica spectrum disorders (NMOSD) are rare, debilitating autoimmune diseases of the central nervous system. Many NMOSD patients have antibodies to Aquaporin-4 (AQP4). Prior studies show associations of NMOSD with individual Human Leukocyte Antigen (HLA) alleles and with mutations in the complement pathway and potassium channels. HLA allele associations with NMOSD are inconsistent between populations, suggesting complex relationships between the identified alleles and risk of disease. We used a retrospective case-control approach to identify contributing genetic variants in patients who met the diagnostic criteria for NMOSD and their unaffected family members. Potentially deleterious variants identified in NMOSD patients were compared to members of their families who do not have the disease and to existing databases of human genetic variation. HLA sequences from patients from Belgrade, Serbia, were compared to the frequency of HLA haplotypes in the general population in Belgrade. We analyzed exome sequencing on 40 NMOSD patients and identified rare inherited variants in the complement pathway and potassium channel genes. Haplotype analysis further detected two haplotypes, HLA-A*01, B*08, DRB1*03 and HLA-A*01, B*08, C*07, DRB1*03, DQB1*02, which were more prevalent in NMOSD patients than in unaffected individuals. In silico modeling indicates that HLA molecules within these haplotypes are predicted to bind AQP4 at several sites, potentially contributing to the development of autoimmunity. Our results point to possible autoimmune and neurodegenerative mechanisms that cause NMOSD, and can be used to investigate potential NMOSD drug targets.
Rosas-Umbert M, Gunst JD, Pahus MH, Olesen R, Schleimann M, Denton PW, Ramos V, Ward A, Kinloch NN, Copertino DC, Escriba T, Llano A, Brumme ZL, Jones RB, Mothe B, Brander C, Fox J, Nussenzweig MC, Fidler S, Caskey M, Tolstrup M, Sogaard OS
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Administration of broadly neutralizing anti-HIV-1 antibodies at ART initiation maintains long-term CD8(+) T cell immunity

NATURE COMMUNICATIONS 2022 OCT 29; 13(1):? Article 6473
In simian-human immunodeficiency virus (SHIV)-infected non-human primates, broadly neutralizing antibodies (bNAbs) against the virus appear to stimulate T cell immunity. To determine whether this phenomenon also occurs in humans we measured HIV-1-specific cellular immunity longitudinally in individuals with HIV-1 starting antiviral therapy (ART) with or without adjunctive bNAb 3BNC117 treatment. Using the activation-induced marker (AIM) assay and interferon-gamma release, we observe that frequencies of Pol- and Gag-specific CD8(+) T cells, as well as Gag-induced interferon-gamma responses, are significantly higher among individuals that received adjunctive 3BNC117 compared to ART-alone at 3 and 12 months after starting ART. The observed changes in cellular immunity were directly correlated to pre-treatment 3BNC117-sensitivity. Notably, increased HIV-1-specific immunity is associated with partial or complete ART-free virologic control during treatment interruption for up to 4 years. Our findings suggest that bNAb treatment at the time of ART initiation maintains HIV-1-specific CD8(+) T cell responses that are associated with ART-free virologic control. Broadly neutralising anti-HIV-1 antibody (bNAb) administration in nonhuman primates has been shown to stimulate adaptive T cell-specific immunity, with infection prevention observed. In this work, the authors longitudinally analyse HIV-1 specific cellular immunity in HIV-1- infected individuals starting ART with or without adjunctive bNAb treatment.
Bachelez H, Barker J, Burden AD, Navarini AA, Krueger JG
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Generalized pustular psoriasis is a disease distinct from psoriasis vulgaris: evidence and expert opinion

Introduction: Generalized pustular psoriasis (GPP) is a rare, severe, clinically heterogeneous disease characterized by flares of widespread, noninfectious, macroscopically visible pustules that occur with or without systemic inflammation, and are associated with significant morbidity and mortality. Historically, GPP has been classified as a variant of psoriasis vulgaris (PV, or plaque psoriasis); however, accumulating evidence indicates that these are distinct conditions, requiring different treatment approaches. Areas covered: In this perspective article we review evidence that supports the classification of GPP as distinct from PV. Expert opinion: The histopathologic and clinical appearance of GPP is distinct from that of PV and fundamental differences exist between the two conditions in terms of genetic causes and expression-related mechanisms of disease development. GPP results from dysregulation of the innate immune system, with disruption of the interleukin (IL)-36 inflammatory pathway, induction of inflammatory keratinocyte responses, and recruitment of neutrophils. PV is driven by the adaptive immune system, with a key role played by IL-17. Considering GPP as a separate disease will enable greater focus on its specific pathogenesis and the needs of patients. Many treatments for PV have insufficient efficacy in GPP and a therapeutic approach developed specifically for GPP might lead to better patient outcomes. PLAIN LANGUAGE SUMMARY Generalized pustular psoriasis (GPP) is a rare disease. During episodes of worsening disease, the immune system attacks the skin. This causes large areas of skin to become red and painful, pus-filled blisters suddenly form. Some people with GPP have a history of another, more common, skin condition called psoriasis vulgaris (PV). People with PV develop patches of scaly, itchy skin. In the past, GPP was classed as a type of PV and treated with the same medicines. However, these medicines do not work well in GPP. Researchers now understand more about what causes GPP and how it differs from PV. GPP can cause medical problems throughout the body, leading to life-threatening complications. This means that people with GPP often need urgent medical treatment in hospitals. People with PV are mostly treated outside of hospitals. Any other medical problems are not usually due to PV itself. Researchers have found several genes that are altered in people with GPP and PV, and they differ between the two diseases. For example, changes in a gene called IL36RN are common in GPP but are not seen in PV. The skin of people with these two diseases also looks different under a microscope. Knowing more about GPP and how it differs from PV will help people with GPP to be diagnosed more quickly. It will also help researchers to develop new medicines specifically for GPP, so people can receive better treatment in the future.
Deborde S, Gusain L, Powers A, Marcadis A, Yu YS, Chen CH, Frants A, Kao E, Tang LH, Vakiani E, Amisaki M, Balachandran VP, Calo A, Omelchenko T, Jessen KR, Reva B, Wong RJ
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Reprogrammed Schwann Cells Organize into Dynamic Tracks that Promote Pancreatic Cancer Invasion

CANCER DISCOVERY 2022 OCT; 12(10):2454-2473
Nerves are a component of the tumor microenvironment contributing to cancer pro-gression, but the role of cells from nerves in facilitating cancer invasion remains poorly understood. Here we show that Schwann cells (SC) activated by cancer cells collectively function as tumor-activated Schwann cell tracks (TAST) that promote cancer cell migration and invasion. Nonmyeli-nating SCs form TASTs and have cell gene expression signatures that correlate with diminished survival in patients with pancreatic ductal adenocarcinoma. In TASTs, dynamic SCs form tracks that serve as cancer pathways and apply forces on cancer cells to enhance cancer motility. These SCs are activated by c-Jun, analogous to their reprogramming during nerve repair. This study reveals a mechanism of cancer cell inva-sion that co-opts a wound repair process and exploits the ability of SCs to collectively organize into tracks. These findings establish a novel paradigm of how cancer cells spread and reveal therapeutic opportunities. SIGNIFICANCE: How the tumor microenvironment participates in pancreatic cancer progression is not fully understood. Here, we show that SCs are activated by cancer cells and collectively organize into tracks that dynamically enable cancer invasion in a c-Jun-dependent manner.
Yang S, Hiotis G, Wang Y, Chen JJ, Wang JH, Kim M, Reinherz EL, Walz T
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Dynamic HIV-1 spike motion creates vulnerability for its membrane-bound tripod to antibody attack

NATURE COMMUNICATIONS 2022 OCT 27; 13(1):? Article 6393
Vaccines targeting HIV-1's gp160 spike protein are stymied by high viral mutation rates and structural chicanery. gp160's membrane-proximal external region (MPER) is the target of naturally arising broadly neutralizing antibodies (bnAbs), yet MPER-based vaccines fail to generate bnAbs. Here, nanodisc-embedded spike protein was investigated by cryo-electron microscopy and molecular-dynamics simulations, revealing spontaneous ectodomain tilting that creates vulnerability for HIV-1. While each MPER protomer radiates centrally towards the three-fold axis contributing to a membrane-associated tripod structure that is occluded in the upright spike, tilting provides access to the opposing MPER. Structures of spike proteins with bound 4E10 bnAb Fabs reveal that the antibody binds exposed MPER, thereby altering MPER dynamics, modifying average ectodomain tilt, and imposing strain on the viral membrane and the spike's transmembrane segments, resulting in the abrogation of membrane fusion and informing future vaccine development. The membrane-proximal external region of HIV-1 spike protein is a broadly neutralizing antibody target. Here, cryo-electron microscopy and molecular dynamics reveal spontaneous ectodomain tilting, a vulnerability exploitable for vaccine design.
Shebl B, Ng D, Lalazar G, Rosemore C, Finkelstein TM, Migler RD, Zheng GR, Zhang PY, Jiang CS, Qureshi A, Vaughan R, Yarchoan M, de Jong YP, Rice CM, Coffino P, Ortiz MV, Zhou DH, Simon SM
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Targeting BCL-XL in fibrolamellar hepatocellular carcinoma

JCI INSIGHT 2022 SEP 8; 7(17):? Article e161820
Fibrolamellar hepatocellular carcinoma (FLC) is a rare and often lethal liver cancer with no proven effective systemic therapy. Inhibition of the antiapoptotic protein BCL-XL was found to synergize with a variety of systemic therapies in vitro using cells dissociated from patient-derived xenografts (PDX) of FLC or cells dissociated directly from surgical patient resections. As BCL-XL is physiologically expressed in platelets, prior efforts to leverage this vulnerability in other cancers have been hampered by severe thrombocytopenia. To overcome this toxicity, we treated FLC models with DT2216, a proteolysis targeting chimera (PROTAC) that directs BCL-XL for degradation via the von Hippel-Lindau (VHL) E3 ligase, which is minimally expressed in platelets. The combination of irinotecan and DT2216 in vitro on cells directly acquired from patients or in vivo using several xenografts derived from patients with FLC demonstrated remarkable synergy and at clinically achievable doses not associated with significant thrombocytopenia.
Cheng HY, Jarvis ED, Fedrigo O, Koepfli KP, Urban L, Gemmell NJ, Li H
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Haplotype-resolved assembly of diploid genomes without parental data

Routine haplotype-resolved genome assembly from single samples remains an unresolved problem. Here we describe an algorithm that combines PacBio HiFi reads and Hi-C chromatin interaction data to produce a haplotype-resolved assembly without the sequencing of parents. Applied to human and other vertebrate samples, our algorithm consistently outperforms existing single-sample assembly pipelines and generates assemblies of similar quality to the best pedigree-based assemblies.
Kim M, Mikhaylov D, Rangel SM, Pavel AB, He H, Renert-Yuval Y, Del Duca E, Malik K, Huynh T, Ibler E, Sun M, Zhang N, Estrada Y, Krueger J, Paller AS, Guttman-Yassky E
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Transcriptomic Analysis of the Major Orphan Ichthyosis Subtypes Reveals Shared Immune and Barrier Signatures

Preliminary work suggested upregulation of inflammatory pathways in patients with common forms of ichthyosis. However, a comprehensive characterization of skin from various ichthyosis subtypes is unavailable, precluding the development of targeted treatments. Thus, we sought to characterize the immune and barrier profiles of common and subtype-specific skin transcriptomes in a large group of patients with ichthyosis. We performed a global RNA-sequencing analysis in 54 patients with ichthyosis (7 with Netherton syndrome, 13 with epidermolytic ichthyosis, 16 with lamellar ichthyosis, and 18 with congenital ichthyosiform erythroderma) and 40 healthy controls. Differentially expressed genes were defined on the basis of fold changes > 2 and false discovery rate < 0.05 criteria. We found robust and significant T helper (Th) 22/Th17 skewing in all subtypes (e.g., IL-17A/C/F, S100A7/8/9/12; P < 0.001) with modest changes in Th2 pathway, primarily in Netherton syndrome, and Th1 skewing in congenital ichthyosiform erythroderma. Across all subtypes (less evident in epidermolytic ichthyosis), lipid metabolism and barrier junction markers were downregulated (e.g., FA2H, CDH10/ 11/12/2; P < 0.05), whereas epidermal cornification and proliferation measures were upregulated (e.g., SPRR1A/ 1B/2C/2G, EREG; P < 0.05). Our findings suggest that the common ichthyosis variants share aberrations in Th17/ Th22 and barrier function, with minimal Th2 modulation. This may help to elucidate the pathogeneses of these subtypes and inform the development of subtype-specific treatments.