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Found 37769 matches. Displaying 1501-1510
Silasi R, Keshari RS, Regmi G, Lupu C, Georgescu C, Simmons JH, Wallisch M, Kohs TCL, Shatzel JJ, Olson SR, Lorentz CU, Puy C, Tucker EI, Gailani D, Strickland S, Gruber A, McCarty OJT, Lupu F
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Factor XII plays a pathogenic role in organ failure and death in baboons challenged with Staphylococcus aureus

BLOOD 2021 JUL 15; 138(2):178-189
Activation of coagulation factor (F) XI promotes multiorgan failure in rodent models of sepsis and in a baboon model of lethal systemic inflammation induced by infusion of heat-inactivated Staphylococcus aureus. Here we used the anticoagulant FXII-neutralizing antibody 5C12 to verify the mechanistic role of FXII in this baboon model. Compared with untreated control animals, repeated 5C12 administration before and at 8 and 24 hours after bacterial challenge prevented the dramatic increase in circulating complexes of contact system enzymes FXIIa, FXIa, and kallikrein with antithrombin or C1 inhibitor, and prevented cleavage and consumption of high-molecular-weight kininogen. Activation of several coagulation factors and fibrinolytic enzymes was also prevented. D-dimer levels exhibited a profound increase in the untreated animals but not in the treated animals. The antibody also blocked the increase in plasma biomarkers of inflammation and cell damage, including tumor necrosis factor, interleukin (IL)-1 beta, IL-6, IL-8, IL-10, granulocyte-macrophage colony-stimulating factor, nucleosomes, and myeloperoxidase. Based on clinical presentation and circulating biomarkers, inhibition of FXII prevented fever, terminal hypotension, respiratory distress, and multiorgan failure. All animals receiving 5C12 had milder and transient clinical symptoms and were asymptomatic at day 7, whereas untreated control animals suffered irreversible multiorgan failure and had to be euthanized within 2 days after the bacterial challenge. This study confirms and extends our previous finding that at least 2 enzymes of the contact activation complex, FXIa and FXIIa, play critical roles in the development of an acute and terminal inflammatory response in baboons challenged with heat-inactivated S aureus.
Lavin RC, Johnson C, Ahn YM, Kremiller KM, Sherwood M, Patel JS, Pan Y, Russo R, MacGilvary NJ, Giacalone D, Kevorkian YL, Zimmerman MD, Glickman JF, Freundlich JS, Tan SM
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Targeting Mycobacterium tuberculosis response to environmental cues for the development of effective antitubercular drugs

PLOS BIOLOGY 2021 JUL; 19(7):? Article e3001355
Sensing and response to environmental cues, such as pH and chloride (Cl-), is critical in enabling Mycobacterium tuberculosis (Mtb) colonization of its host. Utilizing a fluorescent reporter Mtb strain in a chemical screen, we have identified compounds that dysregulate Mtb response to high Cl- levels, with a subset of the hits also inhibiting Mtb growth in host macrophages. Structure-activity relationship studies on the hit compound "C6," or 2-(4-((2-(ethylthio)pyrimidin-5-yl)methyl)piperazin-1-yl)benzo[d]oxazole, demonstrated a correlation between compound perturbation of Mtb Cl- response and inhibition of bacterial growth in macrophages. C6 accumulated in both bacterial and host cells, and inhibited Mtb growth in cholesterol media, but not in rich media. Subsequent examination of the Cl- response of Mtb revealed an intriguing link with bacterial growth in cholesterol, with increased transcription of several Cl--responsive genes in the simultaneous presence of cholesterol and high external Cl- concentration, versus transcript levels observed during exposure to high external Cl- concentration alone. Strikingly, oral administration of C6 was able to inhibit Mtb growth in vivo in a C3HeB/FeJ murine infection model. Our work illustrates how Mtb response to environmental cues can intersect with its metabolism and be exploited in antitubercular drug discovery.
Brivanlou AH, Gleicher N
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The evolution of our understanding of human development over the last 10 years

NATURE COMMUNICATIONS 2021 JUL 29; 12(1):? Article 4615
As it fulfills an irresistible need to understand our own origins, research on human development occupies a unique niche in scientific and medical research. In this Comment, we explore the progress in our understanding of human development over the past 10 years. The focus is on basic research, clinical applications, and ethical considerations.
Beziat V, Rapaport F, Hu JF, Titeux M, des Claustres MB, Bourgey M, Griffin H, Bandet E, Ma CS, Sherkat R, Rokni-Zadeh H, Louis DM, Changi-Ashtiani M, Delmonte OM, Fukushima T, Habib T, Guennoun A, Khan T, Bender N, Rahman M, About F, Yang R, Rao G, Rouzaud C, Li JW, Shearer D, Balogh K, Al Ali F, Ata M, Dabiri S, Momenilandi M, Nammour J, Alyanakian MA, Leruez-Ville M, Guenat D, Materna M, Marcot L, Vladikine N, Soret C, Vahidnezhad H, Youssefian L, Saeidian AH, Uitto J, Catherinot E, Navabi SS, Zarhrate M, Woodley DT, Jeljeli M, Abraham T, Belkaya S, Lorenzo L, Rosain J, Bayat M, Lanternier F, Lortholary O, Zakavi F, Gros P, Orth G, Abel L, Pretet JL, Fraitag S, Jouanguy E, Davis MM, Tangye SG, Notarangelo LD, Marr N, Waterboer T, Langlais D, Doorbar J, Hovnanian A, Christensen N, Bossuyt X, Shahrooei M, Casanova JL
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Humans with inherited T cell CD28 deficiency are susceptible to skin papillomaviruses but are otherwise healthy

CELL 2021 JUL 8; 184(14):3812-3828.e30
We study a patient with the human papilloma virus (HPV)-2-driven ``tree-man'' phenotype and two relatives with unusually severe HPV4-driven warts. The giant horns form an HPV-2-driven multifocal benign epithelial tumor overexpressing viral oncogenes in the epidermis basal layer. The patients are unexpectedly homozygous for a private CD28 variant. They have no detectable CD28 on their T cells, with the exception of a small contingent of revertant memory CD4(+) T cells. T cell development is barely affected, and T cells respond to CD3 and CD2, but not CD28, costimulation. Although the patients do not display HPV-2- and HPV-4-reactive CD4(+) T cells in vitro, they make antibodies specific for both viruses in vivo. CD28-deficient mice are susceptible to cutaneous infections with themouse papillomavirus MmuPV1. The control of HPV-2 and HPV-4 in keratinocytes is dependent on the T cell CD28 co-activation pathway. Surprisingly, human CD28-dependent T cell responses are largely redundant for protective immunity.
Olesen CM, Ingham AC, Thomsen SF, Clausen ML, Andersen PS, Edslev SM, Yuksel YT, Guttman-Yassky E, Agner T
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Changes in Skin and Nasal Microbiome and Staphylococcal Species Following Treatment of Atopic Dermatitis with Dupilumab

MICROORGANISMS 2021 JUL; 9(7):? Article 1487
Investigation of changes in the skin microbiome following treatment of atopic dermatitis (AD) with dupilumab may provide valuable insights into the skin microbiome as a therapeutic target. The aim of this study is to assess changes in the AD skin microbiome following treatment of AD with dupilumab (n = 27). E-swabs were collected from nose, lesional, and nonlesional skin before and after 16 weeks of dupilumab therapy, and the microbiome was analyzed by 16S rRNA and tuf gene sequencing. Data for 17 patients with milder disease receiving treatment with non-targeted therapies are also presented. The results show that both groups experienced clinical improvement (p < 0.001) following dupilumab therapy and that Shannon diversity increased and bacterial community structure changed. The relative abundance of the genus Staphylococcus (S.) and S. aureus decreased, while that of S. epidermidis and S. hominis increased. No significant changes were observed for patients receiving non-targeted treatments. The increases in S. epidermidis and S. hominis and the decrease in S. aureus correlated with clinical improvement. Furthermore, changes in S. hominis and S. epidermidis correlated inversely with S. aureus. In conclusion, treatment with dupilumab significantly changed the skin microbiome and decreased S. aureus. Our results suggest a favorable role of commensal staphylococci in AD.
Savage KT, Singh V, Patel ZS, Yannuzzi CA, McKenzie-Brown AM, Lowes MA, Orenstein LAV
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Pain management in hidradenitis suppurativa and a proposed treatment algorithm

JOURNAL OF THE AMERICAN ACADEMY OF DERMATOLOGY 2021 JUL; 85(1):187-199
Pain contributes substantially to reduced quality of life in individuals living with hidradenitis suppurativa (HS). Although improved understanding of HS pathogenesis and treatment has resulted in improved evidence-based HS management guidelines, comprehensive pain management guidelines have yet to be developed. Few HS-specific data exist to guide pharmacologic analgesia; however, recognizing HS pain as either acute or chronic and predominantly nociceptive (aching and gnawing pain due to tissue damage) versus neuropathic (burning-type pain due to somatosensory nervous system dysfunction) provides a conceptual framework for applying outside pain management practices to HS management. This article incorporates the best available evidence from the HS and pain literature to propose an HS pain algorithm that integrates psychological, pharmacologic, and complementary and alternative treatment modalities.
Xu JL, Xu K, Jung S, Conte A, Lieberman J, Muecksch F, Lorenzi JCC, Park S, Schmidt F, Wang ZJ, Huang YX, Luo Y, Nair MS, Wang PF, Schulz JE, Tessarollo L, Bylund T, Chuang GY, Olia AS, Stephens T, Teng IT, Tsybovsky Y, Zhou TQ, Munster V, Ho DD, Hatziioannou T, Bieniasz PD, Nussenzweig MC, Kwong PD, Casellas R
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Nanobodies from camelid mice and llamas neutralize SARS-CoV-2 variants

NATURE 2021 JUL 8; 595(7866):278-282
Since the start of the COVID-19 pandemic, SARS-CoV-2 has caused millions of deaths worldwide. Although a number of vaccines have been deployed, the continual evolution of the receptor-binding domain (RBD) of the virus has challenged their efficacy. In particular, the emerging variants B.1.1.7, B.1.351 and P.1 (first detected in the UK, South Africa and Brazil, respectively) have compromised the efficacy of sera from patients who have recovered from COVID-19 and immunotherapies that have received emergency use authorization(1-3). One potential alternative to avert viral escape is the use of camelid VHHs (variable heavy chain domains of heavy chain antibody (also known as nanobodies)), which can recognize epitopes that are often inaccessible to conventional antibodies(4). Here, we isolate anti-RBD nanobodies from llamas and from mice that we engineered to produce VHHs cloned from alpacas, dromedaries and Bactrian camels. We identified two groups of highly neutralizing nanobodies. Group 1 circumvents antigenic drift by recognizing an RBD region that is highly conserved in coronaviruses but rarely targeted by human antibodies. Group 2 is almost exclusively focused to the RBD-ACE2 interface and does not neutralize SARS-CoV-2 variants that carry E484K or N501Y substitutions. However, nanobodies in group 2 retain full neutralization activity against these variants when expressed as homotrimers, and-to our knowledge-rival the most potent antibodies against SARS-CoV-2 that have been produced to date. These findings suggest that multivalent nanobodies overcome SARS-CoV-2 mutations through two separate mechanisms: enhanced avidity for the ACE2-binding domain and recognition of conserved epitopes that are largely inaccessible to human antibodies. Therefore, although new SARS-CoV-2 mutants will continue to emerge, nanobodies represent promising tools to prevent COVID-19 mortality when vaccines are compromised.
Yamashita M, Kuehn HS, Okuyama K, Okada S, Inoue Y, Mitsuiki N, Imai K, Takagi M, Kanegane H, Takeuchi M, Shimojo N, Tsumura M, Padhi AK, Zhang KYJ, Boisson B, Casanova JL, Ohara O, Rosenzweig SD, Taniuchi I, Morio T
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A variant in human AIOLOS impairs adaptive immunity by interfering with IKAROS

NATURE IMMUNOLOGY 2021 JUL; 22(7):893-903
The zinc-finger transcription factor IKAROS is essential for B cell development. Taniuchi, Morio and colleagues identify a human kindred presenting with B cell immunodeficiency that was caused by a heterozygous missense mutation in IKZF3 encoding the related AIOLOS protein. AIOLOS(G159R) is a mutant protein that interferes with both wild-type AIOLOS and IKAROS by forming heterodimers that bind to aberrant DNA-binding sites and prevent normal expression of IKAROS-dependent genes. In the present study, we report a human-inherited, impaired, adaptive immunity disorder, which predominantly manifested as a B cell differentiation defect, caused by a heterozygous IKZF3 missense variant, resulting in a glycine-to-arginine replacement within the DNA-binding domain of the encoded AIOLOS protein. Using mice that bear the corresponding variant and recapitulate the B and T cell phenotypes, we show that the mutant AIOLOS homodimers and AIOLOS-IKAROS heterodimers did not bind the canonical AIOLOS-IKAROS DNA sequence. In addition, homodimers and heterodimers containing one mutant AIOLOS bound to genomic regions lacking both canonical motifs. However, the removal of the dimerization capacity from mutant AIOLOS restored B cell development. Hence, the adaptive immunity defect is caused by the AIOLOS variant hijacking IKAROS function. Heterodimeric interference is a new mechanism of autosomal dominance that causes inborn errors of immunity by impairing protein function via the mutation of its heterodimeric partner.
The mu opioid receptor antagonist/kappa opioid receptor (KOR) partial agonist nalmefene (NMF), a close structural analog of naltrexone (NTX), has been shown to reduce cocaine reward in preclinical models. Given the greater KOR potency and improved bioavailability compared to NTX, NMF may be a promising pharmacotherapeutic for cocaine use disorder (CUD). Here we examine the effects of NMF pretreatment on chronic daily extended access (4h) cocaine intravenous self-administration (IVSA) in adult male C57Bl/6J mice. Methods: separate groups of mice had daily 4h cocaine IVSA sessions (0.25 or 0.5 mg/kg/inf, FR1) for 14 days. Starting on day 8, mice were pretreated with NMF (0, 1, or 10 mg/kg) 30m before each session. A separate group of mice acquired cocaine IVSA [seven days FR1 then four FR3 of 4h daily sessions (0.5 mg/kg/inf)] prior to a single progressive ratio 3 session to examine the effect of 1 mg/kg NMF on cocaine motivation. Results: No significant effect of NMF pretreatment on cocaine intake was observed. Acute pretreatment of 1 mg/kg NMF significantly potentiated cocaine motivation as measured by progressive ratio breakpoint. Conclusions: NMF did not significantly attenuate cocaine intake and increased motivation for cocaine suggesting that NMF may not be suitable for non-abstinent CUD patients. Further research is needed with KOR selective partial or full agonists to determine their effect on cocaine reinforcement.
Adura C, Aliaga C, Silva F, Vera C, Pino E, Celis F, Aracena A, Tirapegui C
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A simple method to estimate the mean number of lipophilic molecules on nanoparticle surfaces by fluorescence measurements

NANOTECHNOLOGY 2021 JUL 30; 32(31):? Article 315711
Measurements of fluorescence intensity of the hydrophobic pyridinium salt (DTPSH) remaining in the organic phase after partition experiments in the DCM/H2O system allowed an approximate method to be developed to estimate the mean number of molecules (N = 942) on the surface of 22.8 nm gold nanoparticles and the separation (1.89 nm) between these organic molecules. This protocol is based on the ability that the organic molecules possess to coat the surface of the nanoparticle, which can migrate from the organic to the aqueous phase as a result of the driving force of the strong binding of sulfur to gold. To validate our estimation, we used a projection of the results obtained by Wales and Ulker to solve the Thomson problem, a mathematicians' challenge, used as a model to calculate the mean distance (1.82 nm) separating particles on the surface, in excellent agreement with the results obtained by our method. The quality of results, the simplicity of calculations, the low fluorescence detection limit, and the inexpensive materials, recommend this procedure for rapid estimates of the mean number of molecules on the surface of nanoparticles.