bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of the Substrate Envelope for Multidrug‐Resistant HIV‐1 Protease
Authors: Liu Zhigang , Yedidi Ravikiran , Brunzelle Joseph , Kovari Iulia , Kovari Ladislau 
Published: June 2021

Objectives: Determine the substrate envelope for MDR HIV‐1 protease to guide antiviral drug design.Background: HIV‐1 protease, required for HIV replication, is a critical therapeutic target in the treatment of AIDS. Under drug selection pressure, HIV‐1 protease mutations give raise to multiple drug resistance. Crystallographic studies on substrate complexes of wide‐type HIV‐1 protease revealed a consensus substrate‐shape which is defined as the ‘substrate‐envelope’. Many drug resistant mutations occur where inhibitors protrude from this substrate‐envelope and may predict potential resistance.Methods and Results: We focus on MDR HIV‐1 protease to propose atomic details of drug resistance and the drug design of novel inhibitors. We co‐crystallized HIV‐1 protease with nine natural Gag and Gag‐Pol cleavage site peptides and solved the structures of these nine complexes. Based on these structural studies we determined the substrate envelope.Conclusions: All the nine natural substrate peptides show induced fit to MDR HIV‐1 protease, although the extent of induced fit varies. Furthermore, the positions of the substrate peptides are different from those in wide‐type HIV‐1 protease, which gives a unique substrate envelope of MDR HIV‐1 protease. This project is funded by NIH.
CD27 plus CD28 Cross‐linking Induces Phosphorylation of p38 in CD4+CD45RO+ T Cells
Authors: Tamma Seetha M. , Balan S. P. , Akshintala S. Deepika 
Published: June 2021

CD27 antigen is a 120 KDa transmembrane protein and a member of nerve growth receptor family. Its expression is predominantly confined to lymphocytes and equally distributed between CD4 and CD8 lymphocytes. It has been reported that CD27 is required for long term maintenance of T cell immunity and was found to rescueCD28(−/−) T cells from death at the onset of division. We investigated the role of CD27 on resting and memory CD4+ T cells. We isolated human CD4+CD45RA+ and CD4+CDRO+ subsets using Dynal magnetic beads and cultures were set up by cross‐linking with antibodies as indicated: CD3 + CD28; CD27 alone; CD27 + CD3; CD27 + CD28; CD28 alone and control cells. MAPK ERK2 phosphorylation appears to be similar in both RA and RO populations when stimulated with CD27 plus CD28. We report that CD27 plus CD28XL resulted in enhanced and accelerated phosphorylation of p38 MAPK, activation peaked at 10 minutes and decreased by 2 hours in RO+ cells when compared with that in RA+ cells. CD27 on its own induced phosphorylation of ERK2 slightly higher than that in control, where as no phosphorylation of p38 was observed in both populations following cross‐linking with CD27 alone. This data suggests that RA and RO populations respond differently to signals transmitted through coreceptors CD27 plus CD28.Grant from C.W. Post Campus Research Committee of Long Island University, New York supported this work.
Osteoclast differentiation through rheumatoid synovial fibroblasts could be regulated by TLR‐3 pathway
Authors: Lee Sang‐Heon , Kim Hae‐Rim , Kim Kyoung‐Woon , Cho Mi‐La , Kim Ho‐Youn 
Published: June 2021

This study was undertaken to determine the effect of toll‐like receptor‐3 (TLR‐3) on the regulation of osteoclastogenic activity in rheumatoid arthritis (RA) fibroblast‐like synoviocytes (FLS).The expression of receptor activator of nuclear factor kappa B ligane (RANKL) mRNA and protein in RA FLS after TLR3 activation were determined using RT‐PCR, real time PCR, western blot and immunostaining. Human monocytes were co‐cultured with RA FLS which were pre‐stimulated by polyI:C, the TLR3 ligand, and subsequently stained for tartate‐resistant acid phosphatase (TRAP) activity. The expression of TLR3 and RANKL was much higher in RA synovium than in OA synovium. TLR3 activation induced RANKL expression in RA FLS, but not in OA FLS or normal skin fibroblasts. TLR3 activation also induced the production of IL‐1beta, but no effect on TNF‐alpha in RA FLS. Inhibition of IL‐1beta reversed the TLR3‐induced upregulation of RANKL expression. When human monocytes were co‐cultured with TLR3‐activated RA FLS, the expression of TRAP, RANK, cathepsin K, calcitonin receptor, and MMP‐9 was upregulated, reflecting the osteoclast differentiation.Our results suggest that the RA FLS promotes osteoclastogenesis via TLR3 both directly and indirectly by RANKL induction. Targeting between TLR3 pathways and osteoclastogenesis of RA FLS may be a promising approach to prevent joint destruction in RA.
Pulmonary arterial muscularization induced by a Th2 immune response
Authors: Grunig Gabriele , de Waal Malefyt Rene , Emson Claire , Louten Jennifer , Voelkel Norbert , Guignabert Christophe , Rabinovitch Marlene , Grunig Ekkehard , Daley Eleen 
Published: June 2021

Pulmonary hypertension and pulmonary arterial muscularization (PAmusc) are seen in many parasitic and autoimmune diseases and in chronic inflammatory lung diseases. The goal of this study was to determine the relationships between the immune response, PAmusc, and pulmonary hypertension. Mice were immunized intraperitoneally and exposed to inhaled soluble antigen intermittently for a prolonged period of time or acutely. The prolonged antigen exposure induced dramatic PAmusc that was dependent on the presence of CD4 T cells, IL‐4 and IL‐13. PAmusc was characterized by neo‐intima formation, cell proliferation, and the expression of smooth muscle cell actin. Surprisingly, PAmusc was not associated with increased right ventricular pressures at rest or following challenge with acute hypoxia. The possibility that PAmusc does not necessarily cause pulmonary hypertension has been suggested by clinical observations in children that may quickly regain normal pulmonary arterial pressures after surgical repair of cardiac defects despite the presence of muscularized pulmonary arteries. In conclusion, our data are the first to show experimentally that the adaptive immune response can cause PAmusc and that severe PAmusc and pulmonary hypertension can be dissociated.Supported by: Flight Attendant Medical Research Inst., Stony Wold Herbert Fund, Am. Lung Association of the City of New York
B‐cell activating factor (BAFF) in a model of systemic lupus erythematosis: expression and rabbit homologue identification
Authors: Yang Jiahui , Pospisil Richard , Ray Satyajit , Mage Rose 
Published: June 2021

To gain further insight into the contribution of BAFF to B‐cell hyperactivity in systemic lupus erythematosus (SLE), we studied BAFF expression in our noninbred rabbit lupus model (Rai et al. J. Immunol. 179: 660, 2006). We also cloned cDNA encoding the rabbit homolog (rabBAFF) and identified a predicted rabbit BAFF cDNA and genomic exons in the Ensembl database. Before immunization with a peptide sequence from the rabbit N‐methyl‐d‐aspartate receptor NR2b on multiple Ag‐branched polylysine backbones (GR‐MAP8), rabBAFF was most strongly expressed on IgM+ B cells, and intermediate on CD14+ cells from peripheral blood mononuclear cells (PBMC). In spleen, rabBAFF can be detected on IgM+ B cells, and CD4+ T cells. After 1st and 2nd boosts with GR‐MAP8, BAFF detected on PBMC was significantly decreased; it then started increasing after 3rd through 5th boosts. This was negatively correlated with the levels of autoantibodies in serum. Real‐time PCR assays of mRNA from PBMC and spleen are in progress. This study broadens our knowledge of the expression of this important member of the TNF superfamily in a noninbred pedigreed rabbit model of SLE where it may specifically regulate B lymphocyte proliferation and survival.This research was supported by the intramural research program of the NIH, NIAID and the Oak Ridge Associated Universities.
Genetic and environmental factors complement EAE susceptibility in tyk2 mutant B10.DI‐H2q/SgJ (DI) mice
Authors: Spach Karen M , Noubade Rajkumar , Blankenhorn Elizabeth P , Teuscher Cory 
Published: June 2021

Multiple sclerosis (MS), and its mouse model EAE, are autoimmune (AI) diseases that depend on both genetic and environmental factors. Shared immunopathology genes, e.g., tyrosine kinase‐2 (Tyk2), may also be shared AI disease genes. DI mice have a single 2538 G → A missense mutation in tyk2 making them AI arthritis resistant and T. gondii susceptible, unlike the wild‐type B10.Q/Ai (Ai) substrain. We induced EAE in DI and Ai mice with MOG79‐96‐CFA using a double injection protocol (2×). DI mice were resistant (0/46) to EAE while Ai (32/36) and F1 hybrids (43/50) were susceptible (p < 0.0001). Antigen specific production of RANTES and IFN‐γ were specifically increased in Ai and F1 mice. Thus, tyk2 is a shared AI susceptibility gene, and EAE can be complemented genetically by one wild‐type Tyk2 allele. Next, we tested whether EAE in DI mice could be complemented by environmental factors using MOG79‐96‐CFA + pertussis toxin (1× + PTX). DI mice immunized with 1× + PTX were significantly more susceptible to EAE than 2× immunized mice (33/36 vs. 0/46; p < 0.0001). Only RANTES changed significantly with both genetic and PTX complementation. In summary, tyk2 is both a shared immunopathology and AI disease susceptibility allele that can be complemented both genetically and environmentally. Such SNPs are of considerable significance given the potential role of gene‐by‐environment interaction in MS susceptibility.Research supported by NIH/NINDS R01 NS36526, R01 AI058052, R01 AI41747, P01AI45666‐08P4, and National Multiple Sclerosis Society RG3575A5
Absence of Auto‐Antibodies against Cardiac Troponin I Predicts Improvement of Left Ventricular Function after Acute Myocardial Infarction
Authors: Kaya Ziya , Li Jin , Leuschner Florian , Göser Stefan , Öttl Renate , Reinhardt Lars , Remppis Andrew , Giannitsis Evangelos , Katus Hugo A. 
Published: June 2021

Background: Application of antibodies (Ab) against cardiac troponin I (cTnI) can induce dilation and dysfunction of the heart in mice. But little is known about the clinical relevance of detected cTnI‐Ab.Methods: First, anti‐cTnI and anti‐cTnT Ab titers have been measured in sera from 272 patients with dilated‐ (DCM) and 185 with ischemic‐ (ICM) cardiomyopathy. Secondly, 108 patients with acute myocardial infarction (AMI) were included for a follow‐up study. All 108 patients were treated according to current guidelines. Heart characteristics were determined by magnetic resonance imaging 3–4 days and 6–9 months after AMI.Results: Altogether, in 14,3% of patients with DCM and in 17,3% with ICM an anti‐cTnI IgG‐Ab titer ≥1:80 was measured. In contrast, only in 1,8% of patients with DCM and in 0,5% with ICM an anti‐cTnT IgG‐Ab titer ≥1:80 was detected. Ten out of 108 patients included in the follow‐up study were tested positive for cTnI‐Ab with IgG Ab titers ≥1:160. TnI‐Ab negative patients showed a significant increase in LVF and stroke volume 6–9 months after AMI. In contrast, there was no significant increase in LVF and stroke volume in TnI‐Ab positive patients.Conclusion: We demonstrate for the first time that the prevalence of cTnI‐Abs in patients with AMI has an impact on the improvement of the LVF.
Autoantibodies against Cardiac Troponin I in Patients with Dilated Cardio‐myopathy Predict Improvement of Cardiac Function by Immunoadsorption
Authors: Kaya Ziya , Leuschner Florian , Trimpert Christiane , Göser Stefan , Öttl Renate , Li Jin , Felix Stephan , Dengler Thomas J. , Hugo Katus A. , Staudt Alexander 
Published: June 2021

Aims: Cardiac troponins in blood are the most preferred markers of myocardial damage. It has been shown that the application of antibodies against cardiac troponin I (cTnI) can induce dilation and dysfunction of the heart in mice. In the present study we investigated the presence of cTnI‐antibody in patients with dilated cardiomyopathy (DCM) and the effect of immunoadsorption (IA) on left ventricular function (LVF).Methods: 51 patients with DCM were included. Every patient underwent heart catheterisation including myocardial biopsy and received IA. LVF was determined by echocardiography before and 6 months after IA. Serum samples from each patient (before, 5 days and 6 month after IA) were screened for the presence of cTnI‐Ab. 22 of the 51 patients had positive cTnI‐Ab‐titers. Whereas LVF of patients with positive cTnI‐Ab‐titers improved after IA by +8.1% during follow up of 6 month (p<0.001 vs. baseline), patients with negative cTnI‐Ab‐titers showed an improvement of +4,1% only (p<0.04 vs. baseline). Furthermore, Patients with positive cTnI‐antibody‐titers showed a significantly better clinical improvement after IA (+1 NYHA‐class) than patients without cTnI‐antibodies (+0.5 NYHA‐class; p<0.05).Conclusion: Immunoadsortion therapy is associated with a pronounced improvement of LVF and NYHA‐Class in patients with detectable antibodies against cardiac troponin I.
Lymphotoxin beta receptor is required for the migration and selection of autoreactive T cells in thymic medulla
Authors: Zhu Mingzhao , Chin Robert K , Tumanov Alexei V , Liu Xiaojuan , Fu Yang‐Xin 
Published: June 2021

How organ‐specific central tolerance is established and regulated has been an intriguing question. Lymphotoxin beta receptor (LTβR) deficiency is associated with autoimmune phenotypes characterized by humoral and cellular auto‐reactivity to peripheral organs. We sought to determine the role of LTβR in central tolerance of T cells directed at tissue‐restricted antigens. By tracing the development of OT‐I thymocytes in RIP‐mOVA transgenic mice on either Ltbr+/+ or Ltbr−/− background, we demonstrate that LTβR is necessary for thymic negative selection. LTβR deficiency resulted in a dramatic escape of “neo‐self” specific OT‐I cells that persist in circulation and lead to development of peri‐insulitis. When the underlying mechanism was further explored, we found interestingly that LTβR deficiency did not result in reduced thymic expression of mOVA. Instead, LTβR was revealed to control the expression of thymic medullary chemokines (SLC and ELC) which are required for thymocytes migration and negative selection in medulla as was confirmed by using SLC/ELC deficient mice. On the other hand, by tracing the development of OT‐II cells, we did not find any influence of LTβR deficiency on natural Treg positive selection, another arm of central tolerance. Thus, LTβR has been revealed to play an important role in thymic negative selection of organ‐specific thymocytes through thymic medullary chemokines regulation.This research was supported by grants from National Institutes of Health (NIH; AI062026, DK58897 to YXF)
B cells promote Th2 cytokine production and pathophysiology during chronic allergic lung disease
Authors: Lindell Dennis Michael , Lukacs Nicholas W 
Published: June 2021

The role of B cells in chronic allergic lung disease, or asthma, remains controversial. Our goal in these studies was to characterize the role of B cells in a clinically relevant murine model of chronic allergic lung disease, with a focus on B cell antigen presentation.To this end, mice were chronically challenged (eight times total) with cockroach allergen extract, and the lung B cell response was determined. Chronic allergen challenge resulted in the accumulation of large numbers of B cells to the lungs, which expressed MHC II and the costimulatory molecules CD40, CD80 and CD86. In cocultures with CD4+ T cells, purified lung B cells promoted T cell proliferation and antigen‐specific Th2 cytokine production (IL‐4, IL‐5, and IL‐13, but not IFNg). B cell −/− mice (muMT) had attenuated airway hyperresponsiveness, and decreased mucus hypersecretion. The levels of Th2 cytokines in the lungs of B cell −/− mice were decreased relative to B cell sufficient controls, demonstrating that B cells play a role at promoting pathophysiology and Th2 cytokine responses in vivo. Repopulation of B cells into muMT mice significantly increased CD4 T cell responses in the lungs and increased mucus.Collectively, these results suggest that B cell antigen presentation plays an important role in promoting Th2 cytokine and pathophysiology in allergic lung disease.(NIH‐HL031963, HL059178, and T32HL07749)
Cockroach Allergen Induced Asthma in Outbred Mice
Authors: Vaickus Louis Joseph , Natarajan Sudha , Kim Jiyoun , Remick Daniel G 
Published: June 2021

Our lab has previously demonstrated the ability of German cockroach allergens (CRA) to induce allergic‐type airways inflammation in BALB/c mice. This model resembles human allergic asthma in its histology, symptomatology and airways hyperreactivity. We reproduced this model in outbred (ICR) mice to extend our observations and establish a more applicable model to the extremely outbred human population. Mice were given 4.75ug, 2.4ug and 2.4ug of CRA intratracheally on days 0, 14, and 21. Airways hyperresponsiveness (AHR) and cell content of bronchoalveolar lavage fluid was measured 24 hours post final challenge and the results compared to BALB/c mice.Because of the encouraging data this model has produced, and the greater applicability of its genetically diverse background, we believe outbred animal experiments are highly appropriate in simulating human disease.
A single‐step enrichment method for generating highly purified mouse NK cell populations by negative selection
Authors: Tran Jimmy , Kung Sam K.P. , Yuan Ning , Milton Graeme T , Wognum Albertus W , Eaves Allen C , Thomas Terry E , Guilbault Benoit G 
Published: June 2021

Natural Killer (NK) cells play a critical role in innate immunity and tumor immunology. They are particularly difficult to isolate because they are rare and express several markers found on other cell types. Using column‐free immunomagnetic cell separation technology (EasySep®), we sought to develop a single‐step negative selection method for NK cell isolation, where negative selection enables the isolation of cells with minimal impact on cell function. Unwanted cells were cross‐linked to magnetic particles using a highly optimized cocktail of 10 biotinylated antibodies. This enabled us to achieve NK cell purities of 92.3 ± 2.6% (defined as %CD49b+CD3neg; n=6). The isolated cells retained the expression of several markers associated with an NK phenotype, including NKG2D and LY49C/I/F/H. The purified cells could be readily expanded when cultured in the presence of IL‐2 (> 8‐fold expansion after 5 days, n=3). Cr51 release assays demonstrated the cytotoxic capacity of the isolated cells, as specific lysis was detected at an effector to target ratio of 1:1 and 10:1 for both YAC‐1 cells and Daudi B lymphoma cells, the latter being more resistant to NK‐specific killing as expected (n=3). In conclusion, we present here a novel and unique enrichment method for the isolation of pure NK cells in a single step.Supported by the Manitoba Health Research Council and The Dean of Medicine Strategic Research Fund.
Tyrosine Phosphorylation of MAL in TLR4 Signaling and Endotoxin Tolerance
Authors: Piao Wenji , Song Chang , Chen Haiyan , Fitzgerald Katherine A. , O’Neill Luke A.J. , Medvedev Andrei E. 
Published: June 2021

TLR4 recognition of LPS triggers signalosome assembly among TLR4, sorting (e.g. MyD88‐adapter‐like, Mal) and signaling (e.g. MyD88) adapters and kinases, resulting in activation of transcription factors and production of inflammatory mediators. Here we examined whether Mal tyrosine phosphorylation regulates Mal‐TLR4 interactions and signaling. In contrast to wild‐type (WT) Mal, overexpression of tyrosine‐deficient Mal variants with mutated Y86, Y106, and Y159 tyrosine residues impaired Mal tyrosine phosphorylation, interactions with Bruton's tyrosine kinase (Btk), phosphorylation of p38, and NF‐κB activation. LPS triggered tyrosine phosphorylation of endogenous Mal and initiated Mal‐Btk interactions in 293/TLR4/MD‐2 cells and human monocytes that were suppressed in endotoxin‐tolerant cells. Compared to WT‐Mal, Y86A‐ and Y159A‐ Mal variants exhibited higher interactions with TLR4 and MyD88, while associations with IRAK‐2 and TRAF‐6 were not affected. Overexpression of Y86A, Y159A and Y106A Mal in 293/TLR4/MD‐2 cells exerted dominant‐negative effects on TLR4‐inducible p38 phosphorylation and NF‐κB reporter activation. In contrast, tyrosine‐deficient Mal species did not affect NF‐κB activation when signaling was initiated at the post‐receptor level by overexpression of MyD88, IRAK‐2 or TRAF‐6. Thus, tyrosine phosphorylation of Mal is required for TLR signaling, regulates Mal interactions with TLR4 and receptor signaling, and is inhibited in endotoxin tolerance.This work was supported by NIH grant AI‐059524 (to A.E.M.)
Inhibitory effect of glycyrrhizin on the production of CCL2 by various sources of immunosuppressive neutrophils (PMN‐II)
Authors: Jones Vickie C , Shigematsu Kenji , Kobayashi Makiko , Sanford Arthur P , Herndon David N , Suzuki Fujio 
Published: June 2021

Three subtypes of PMN (PMN‐N, PMN‐I and PMN‐II) have been demonstrated. Among them, PMN‐II have been characterized as cells that participate in the increased susceptibility of burned hosts to bacterial translocation‐associated infectious complications. Since host‐mediated antibacterial effects of glycyrrhizin (GL) were demonstrated in these infections, in this study, the inhibitory effects of GL on the CCL2 production by various sources of PMN‐II were examined. CCL2 has been determined as an effector chemokine on the PMN‐II immunosuppressive activity. PMN‐II were prepared from peripheral blood of burn patients by Ficoll‐Hypaque and dextran sedimentations. Also, PMN‐II were induced from band PMN (isolated peripheral blood PMN from healthy volunteers 3 hrs after having exercised for 1 hr) by stimulation with SAC (0.0075%), GM‐CSF (0.1 ng/ml), VEGF (0.1 ng/ml) or terbutaline (β2‐AR agonist, 10−6 M). All of these PMN preparations were identified as PMN‐II by their abilities to produce CCL2 and IL‐10. In the results, the production of CCL2 by PMN‐II isolated from peripheral blood of severely burned patients was inhibited by 10 μg/ml of GL (Minophagen Pharmaceutical Co., Ltd., Tokyo, Japan). Also, the production of CCL2 by PMN‐II preparations, prepared in vitro from band PMN of exercised volunteers after stimulation with SAC, GM‐CSF, VEGF or terbutaline, was inhibited by GL (10 μg/ml). These results suggest that PMN‐II‐associated deficiency of the host antimicrobial resistance may be effectively intervened by GL.This study was supported by SHC NA #8840.
TLR4 enhances resolution of lung inflammation by promoting neutrophil apoptosis
Authors: zhao hang , Dedaj rejmon , zhao gao feng , leu shaw wei , shen lian jun , lien egil , fitzgerald Kate , Shiedlin Aviva , quinn deborah ann , hales charles a 
Published: June 2021

Acute lung injury (ALI), the called acute respiratory distress syndrome in its most severe (ARDS) clinical manifestation, affects about 150,000 patients per year in the US, with recent mortality rates being > 30%. High concentrations of hyaluronan (HA) are found in bronchoalveolar lavage (BAL) fluid of ARDS patients. Neutrophils appear to play a major role in the development of ALI/ARDS. Here we report that in response to inhaled low molecular weight HA (LMW HA), mice lacking the TLR4‐MyD88 independent signaling pathway showed loss of lung epithelial integrity, diffuse alveolar damage, increased interstitial edema, increased inflammatory cytokines and chemokines, including macrophage inflammatory protein (MIP‐2) (a rodent homolog of IL‐8), interleukin (IL)‐6 and KC compared to wild type. In addition, there were large numbers of activated neutrophils in BAL fluid and lung interstitium in TLR4 knock out mice, indicating TLR4 enhances the resolution of inflammation by promoting apoptosis of neutrophils. Our findings show an unrecognized potential for the treatment of ALI/ARDS disorders.This work was supported by a training grant from the NIH (HL007874 to H.Z.)