Detection of Autoantibodies against Aquaporin-1 in the Sera of Patients with Primary Sjögren's Syndrome

Alam, Jehan,Choi, Yun Sik,Koh, Jung Hee,Kwok, Seung-Ki,Park, Sung-Hwan,Song, Yeong Wook,Park, Kyungpyo,Choi, Youngnim 한국조명·전기설비학회 2017 한국조명·전기설비학회 학술대회논문집 Vol. No.

<P>The pathophysiology of glandular dysfunction in Sjögren's syndrome (SS) has not been fully elucidated. Previously, we reported the presence of autoantibodies to AQP-5 in patients with SS, which was associated with a low resting salivary flow. The purpose of this study was to investigate the presence of anti-AQP1 autoantibodies. To detect anti-AQP1 autoantibodies, cell-based indirect immunofluorescence assay was developed using MDCK cells that overexpressed human AQP1. By screening 112 SS and 52 control sera, anti-AQP1 autoantibodies were detected in 27.7% of the SS but in none of the control sera. Interestingly, the sera that were positive for anti-AQP1 autoantibodies also contained anti-AQP5 autoantibodies in the previous study. Different from anti-AQP5 autoantibodies, the presence of anti-AQP1 autoantibodies was not associated with the salivary flow rate. Although anti-AQP1 autoantibodies are not useful as a diagnostic marker, the presence of autoantibodies to AQP1 may be an obstacle to AQP1 gene therapy for SS.</P>

Detection of Autoantibodies against Aquaporin-1 in the Sera of Patients with Primary Sjögren’s Syndrome

Jehan Alam,최윤식,고정희,곽승기,박성환,송영욱,박경표,최영님 대한면역학회 2017 Immune Network Vol.17 No.2

The pathophysiology of glandular dysfunction in Sjögren’s syndrome (SS) has not been fully elucidated. Previously, we reported the presence of autoantibodies to AQP-5 in patients with SS, which was associated with a low resting salivary flow. The purpose of this study was to investigate the presence of anti-AQP1 autoantibodies. To detect anti-AQP1 autoantibodies, cell-based indirect immunofluorescence assay was developed using MDCK cells that overexpressed human AQP1. By screening 112 SS and 52 control sera, anti-AQP1 autoantibodies were detected in 27.7% of the SS but in none of the control sera. Interestingly, the sera that were positive for anti-AQP1 autoantibodies also contained anti-AQP5 autoantibodies in the previous study. Different from anti-AQP5 autoantibodies, the presence of anti-AQP1 autoantibodies was not associated with the salivary flow rate. Although anti-AQP1 autoantibodies are not useful as a diagnostic marker, the presence of autoantibodies to AQP1 may be an obstacle to AQP1 gene therapy for SS.

Potential Role of Bacterial Infection in Autoimmune Diseases: A New Aspect of Molecular Mimicry

Jehan Alam,최영님,김용철 대한면역학회 2014 Immune Network Vol.14 No.1

Molecular mimicry is an attractive mechanism for triggering autoimmunity. In this review, we explore the potential role of evolutionary conserved bacterial proteins in the production of autoantibodies with focus on granulomatosis with polyangiitis (GPA) and rheumatoid arthritis (RA). Seven autoantigens characterized in GPA and RA were BLASTed against a bacterial protein database. Of the seven autoantigens, proteinase 3, type II collagen, binding immunoglobulin protein, glucose-6-phosphate isomerase, α-enolase, and heterogeneous nuclear ribonuclear protein have well- conserved bacterial orthologs. Importantly, those bacterial orthologs are also found in human-associated bacteria. The wide distribution of the highly conserved stress proteins or enzymes among the members of the normal flora and common infectious microorganisms raises a new question on how cross-reactive autoantibodies are not produced during the immune response to these bacteria in most healthy people. Understanding the mechanisms that deselect auto-reactive B cell clones during the germinal center reaction to homologous foreign antigens may provide a novel strategy to treat autoimmune diseases.

N-acetylcysteine and the human serum components that inhibit bacterial invasion of gingival epithelial cells prevent experimental periodontitis in mice

Jehan Alam,백금진,최윤식,김용철,최영님 대한치주과학회 2014 Journal of Periodontal & Implant Science Vol.44 No.6

Purpose: We previously reported that human serum significantly reduces the invasion ofvarious oral bacterial species into gingival epithelial cells in vitro. The aims of the presentstudy were to characterize the serum component(s) responsible for the inhibition of bacterialinvasion of epithelial cells and to examine their effect on periodontitis induced in mice. Methods: Immortalized human gingival epithelial (HOK-16B) cells were infected with various5- (and 6-) carboxy-fluorescein diacetate succinimidyl ester-labeled oral bacteria, includingFusobacterium nucleatum, Provetella intermedia, Porphyromonas gingivalis, andTreponiema denticola, in the absence or presence of three major serum components (humanserum albumin [HSA], pooled human IgG [phIgG] and α1-antitrypsin). Bacterial adhesionand invasion were determined by flow cytometry. The levels of intracellular reactiveoxygen species (ROS) and activation of small GTPases were examined. Experimental periodontitiswas induced by oral inoculation of P. gingivalis and T. denticola in Balb/c mice. Results: HSA and phIgG, but not α1-antitrypsin, efficiently inhibited the invasion of variousoral bacterial species into HOK-16B cells. HSA but not phIgG decreased the adhesion ofF. nucleatum onto host cells and the levels of intracellular ROS in HOK-16B cells. N-acetylcysteine(NAC), a ROS scavenger, decreased both the levels of intracellular ROS and invasionof F. nucleatum into HOK-16B cells, confirming the role of ROS in bacterial invasion. Infection with F. nucleatum activated Rac1, a regulator of actin cytoskeleton dynamics. Not only HSA and NAC but also phIgG decreased the F. nucleatum-induced activation ofRac1. Furthermore, both HSA plus phIgG and NAC significantly reduced the alveolar boneloss in the experimental periodontitis induced by P. gingivalis and T. denticola in mice. Conclusions: NAC and the serum components HSA and phIgG, which inhibit bacterial invasionof oral epithelial cells in vitro, can successfully prevent experimental periodontitis.

Potential Role of Bacterial Infection in Autoimmune Diseases: A New Aspect of Molecular Mimicry

Alam, Jehan,Kim, Yong Chul,Choi, Youngnim The Korean Association of Immunobiologists 2014 Immune Network Vol.14 No.1

Molecular mimicry is an attractive mechanism for triggering autoimmunity. In this review, we explore the potential role of evolutionary conserved bacterial proteins in the production of autoantibodies with focus on granulomatosis with polyangiitis (GPA) and rheumatoid arthritis (RA). Seven autoantigens characterized in GPA and RA were BLASTed against a bacterial protein database. Of the seven autoantigens, proteinase 3, type II collagen, binding immunoglobulin protein, glucose-6-phosphate isomerase, ${\alpha}$-enolase, and heterogeneous nuclear ribonuclear protein have well-conserved bacterial orthologs. Importantly, those bacterial orthologs are also found in human-associated bacteria. The wide distribution of the highly conserved stress proteins or enzymes among the members of the normal flora and common infectious microorganisms raises a new question on how cross-reactive autoantibodies are not produced during the immune response to these bacteria in most healthy people. Understanding the mechanisms that deselect auto-reactive B cell clones during the germinal center reaction to homologous foreign antigens may provide a novel strategy to treat autoimmune diseases.

N-acetylcysteine and the human serum components that inhibit bacterial invasion of gingival epithelial cells prevent experimental periodontitis in mice

Alam, Jehan,Baek, Keum Jin,Choi, Yun Sik,Kim, Yong Cheol,Choi, Youngnim Korean Academy of Periodontology 2014 Journal of Periodontal & Implant Science Vol.44 No.6

Purpose: We previously reported that human serum significantly reduces the invasion of various oral bacterial species into gingival epithelial cells in vitro. The aims of the present study were to characterize the serum component(s) responsible for the inhibition of bacterial invasion of epithelial cells and to examine their effect on periodontitis induced in mice. Methods: Immortalized human gingival epithelial (HOK-16B) cells were infected with various 5- (and 6-) carboxy-fluorescein diacetate succinimidyl ester-labeled oral bacteria, including Fusobacterium nucleatum, Provetella intermedia, Porphyromonas gingivalis, and Treponiema denticola, in the absence or presence of three major serum components (human serum albumin [HSA], pooled human IgG [phIgG] and ${\alpha}1$-antitrypsin). Bacterial adhesion and invasion were determined by flow cytometry. The levels of intracellular reactive oxygen species (ROS) and activation of small GTPases were examined. Experimental periodontitis was induced by oral inoculation of P. gingivalis and T. denticola in Balb/c mice. Results: HSA and phIgG, but not ${\alpha}1$-antitrypsin, efficiently inhibited the invasion of various oral bacterial species into HOK-16B cells. HSA but not phIgG decreased the adhesion of F. nucleatum onto host cells and the levels of intracellular ROS in HOK-16B cells. N-acetyl-cysteine (NAC), a ROS scavenger, decreased both the levels of intracellular ROS and invasion of F. nucleatum into HOK-16B cells, confirming the role of ROS in bacterial invasion. Infection with F. nucleatum activated Rac1, a regulator of actin cytoskeleton dynamics. Not only HSA and NAC but also phIgG decreased the F. nucleatum-induced activation of Rac1. Furthermore, both HSA plus phIgG and NAC significantly reduced the alveolar bone loss in the experimental periodontitis induced by P. gingivalis and T. denticola in mice. Conclusions: NAC and the serum components HSA and phIgG, which inhibit bacterial invasion of oral epithelial cells in vitro, can successfully prevent experimental periodontitis.

<i>Treponema denticola</i> enolase contributes to the production of antibodies against ENO1 but not to the progression of periodontitis

Lee, Ahreum,Kim, Yong C.,Baek, Keumjin,Alam, Jehan,Choi, Yun S.,Rheu, Yaeeun,Shin, Yoo Jin,Kim, Sungtae,Kim, Hyun-Duck,Song, Yeong W.,Choi, Youngnim TaylorFrancis 2018 Virulence Vol.9 No.1

<P><B>ABSTRACT</B></P><P>Autoantibodies against alpha-enolase (ENO1) are often detected in various infectious and autoimmune diseases. Anti-ENO1 antibody titers were reported to be associated with the severity of periodontitis in patients with rheumatoid arthritis. Because the enolase of the periodontal pathogen <I>Treponema denticola</I> (TdEno) has the highest homology with ENO1 among the enolases of human-associated bacteria, we hypothesized that anti-ENO1 autoantibodies produced during the immune response to TdEno may contribute to the progression of periodontitis and tested it in human and mouse systems. In human subjects with healthy periodontium or chronic periodontitis, a strong positive correlation between the levels of anti-TdEno and anti-ENO1 antibodies was observed. In addition, the purified anti-TdEno antibodies recognized ENO1 as well as TdEno in a dot blot, confirming the cross-reactivity between TdEno and ENO1. However, anti-ENO1 antibody titers were not associated with the severity of periodontitis. To further investigate the role of TdEno in the production of anti-ENO1 antibodies and the progression of periodontitis, mice received an oral gavage of <I>P. gingivalis</I> alone, subcutaneous immunization with TdEno alone, or both <I>P. gingivalis</I> oral gavage and TdEno immunization. Immunization with TdEno induced not only anti-TdEno but also anti-mouse Eno1 (mEno1) antibodies and increased the expression of TNFα in the gingival tissues. However, alveolar bone loss was not increased by TdEno immunization. In conclusion, autoreactive anti-ENO1/mEno1 antibodies that are produced as byproducts during the antibody response to TdEno play a minimal role in the progression of periodontitis in the absence of rheumatoid arthritis.</P>