Increased expression of Matrix Metalloproteinase 9 in liver from NZB/W F1 mice received antibody against human parvovirus B19 VP1 unique region protein

Parvovirus B19 Infection Is Associated with the Formation of Neutrophil Extracellular Traps and Thrombosis: A Possible Linkage of the VP1 Unique Region

Neutrophil extracellular traps (NETs) formation, namely NETosis, is implicated in antiphospholipid syndrome (APS)-related thrombosis in various autoimmune disorders such as systemic lupus erythematosus (SLE) and APS. Human parvovirus B19 (B19V) infection is closely associated with SLE and APS and causes various clinical manifestations such as blood disorders, joint pain, fever, pregnancy complications, and thrombosis. Additionally, B19V may trigger the production of autoantibodies, including those against nuclear and phospholipid components. Thus, exploring the connection between B19V, NETosis, and thrombosis is highly relevant. An in vitro NETosis model using differentiated HL-60 neutrophil-like cells (dHL-60) was employed to investigate the effect of B19V-VP1u IgG on NETs formation. A venous stenosis mouse model was used to test how B19V-VP1u IgG-mediated NETs affect thrombosis in vivo. The NETosis was observed in the dHL-60 cells treated with rabbit anti-B19V-VP1u IgG and was inhibited in the presence of either 8-Br-cAMP or CGS216800 but not GSK484. Significantly elevated reactive oxygen species (ROS), myeloperoxidase (MPO), and citrullinated histone (Cit-H3) levels were detected in the dHL60 treated with phorbol myristate acetate (PMA), human aPLs IgG and rabbit anti-B19V-VP1u IgG, respectively. Accordingly, a significantly larger thrombus was observed in a venous stenosis-induced thrombosis mouse model treated with PMA, human aPLs IgG, rabbit anti-B19V-VP1u IgG, and human anti-B19V-VP1u IgG, respectively, along with significantly increased amounts of Cit-H3-, MPO- and CRAMP-positive infiltrated neutrophils in the thrombin sections. This research highlights that anti-B19V-VP1u antibodies may enhance the formation of NETosis and thrombosis and implies that managing and treating B19V infection could lower the risk of thrombosis.

Human parvovirus B19 VP1u Protein as inflammatory mediators induces liver injury in naïve mice

Human parvovirus B19 (B19V) is a human pathogen known to be associated with many non-erythroid diseases, including hepatitis. Although B19V VP1-unique region (B19-VP1u) has crucial roles in the pathogenesis of B19V infection, the influence of B19-VP1u proteins on hepatic injury is still obscure. This study investigated the effect and possible inflammatory signaling of B19-VP1u in livers from BALB/c mice that were subcutaneously inoculated with VP1u-expressing COS-7 cells. The in vivo effects of B19-VP1u were analyzed by using live animal imaging system (IVIS), Haematoxylin-Eosin staining, gel zymography, and immunoblotting after inoculation. Markedly hepatocyte disarray and lymphocyte infiltration, enhanced matrix metalloproteinase (MMP)-9 activity and increased phosphorylation of p38, ERK, IKK-α, IκB and NF-κB (p-p65) proteins were observed in livers from BALB/c mice receiving COS-7 cells expressing B19-VP1u as well as the significantly increased CRP, IL-1β and IL-6. Notably, IFN-γ and phosphorylated STAT1, but not STAT3, were also significantly increased in the livers of BALB/c mice that were subcutaneously inoculated with VP1u-expressing COS-7 cells. These findings revealed the effects of B19-VP1u on liver injury and suggested that B19-VP1u may have a role as mediators of inflammation in B19V infection.

Secondhand smoke induces hepatic apoptosis and fibrosis in hamster fetus

Secondhand smoke (SHS) is an important health issue worldwide. Inhaling SHS during pregnancy could cause abnormalities in the internal tissues of newborns, which may then impair fetal development and even cause severe intrauterine damage and perinatal death. However, the understanding of cytopathic mechanisms of SHS by maternal passive smoking on fetus liver during pregnancy is still limited. This study analyzed the effects of high-dose SHS (SHSH) on fetus liver using a maternal passive smoking animal model. Experiments showed that hepatic matrix metalloproteinase-9 activity and terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick-end labeling-positive cells were significantly increased in livers from fetuses of hamsters treated with SHSH. Similarly, expressions of both extrinsic and intrinsic apoptotic molecules were significantly higher in livers from fetuses of hamsters exposed to SHSH. Additionally, significantly increased inflammatory proteins, including transforming growth factor β, inducible nitric oxide synthase, and interleukin 1β, and fibrotic signaling molecules, including phosphorylated Smad2/3, SP1, and α-smooth muscle actin, were observed in the fetus livers from hamsters treated with SHSH. This study revealed that SHSH not only increased apoptosis through intrinsic and extrinsic pathways in the livers of fetuses from hamsters exposed to SHSH but also augmented hepatic fibrosis via Smad2/3 signaling.

Exacerbating effects of human parvovirus B19 NS1 on liver fibrosis in NZB/W F1 mice

Systemic lupus erythematosus (SLE) is an autoimmune disorder with unknown etiology that impacts various organs including liver. Recently, human parvovirus B19 (B19) is recognized to exacerbate SLE. However, the effects of B19 on liver in SLE are still unclear. Herein we aimed to investigate the effects of B19 on liver in NZB/W F1 mice by injecting subcutaneously with PBS, recombinant B19 NS1, VP1u or VP2, respectively. Our experimental results revealed that B19 NS1 protein significantly enhanced the TGF-β/Smad fibrotic signaling by increasing the expressions of TGF-β, Smad2/3, phosphorylated Smad2/3, Smad4 and Sp1. The consequent fibrosis-related proteins, PAI-1 and α-SMA, were also significantly induced in livers of NZB/W F1 mice receiving B19 NS1 protein. Accordingly, markedly increased collagen deposition was also observed in livers of NZB/W F1 mice receiving B19 NS1 protein. However, no significant difference was observed in livers of NZB/W F1 mice receiving B19 VP1u or VP2 as compared to the controls. These findings indicate that B19 NS1 plays a crucial role in exacerbating liver fibrosis in NZB/W F1 mice through enhancing the TGF-â/Smad fibrotic signaling.

Increased cardiac injury in NZB/W F1 mice received antibody against human parvovirus B19 VP1 unique region protein

Human parvovirus B19 (B19) infection has been postulated to both myocardial injury and development of systemic lupus erythematosus (SLE). However, the influence of anti-B19-VP1u antibodies on cardiac disorders in SLE is still obscure. To elucidate the effects of anti-B19-VP1u IgG in SLE, passive transfer of PBS, normal rabbit IgG or rabbit anti-B19-VP1u IgG was injected intravenously into NZB/W F1 mice, respectively. Significant expression of IL-1β, IL-6 and TNF-α were detected in NZB/W F1 mice receiving rabbit anti-B19-VP1u IgG. Markedly cardiomyocyte disarray and lymphocyte infiltration were observed in left ventricle of hearts from NZB/W F1 mice receiving rabbit anti-B19-VP1u IgG. Additionally, significant increases of matrix metalloproteinase-9 (MMP9) activity and protein expression were detected in left ventricle of hearts from NZB/W F1 mice receiving B19-VP1u IgG. Accordingly, significant increase of phosphorylated p-38 and NF-κB proteins were observed in left ventricle of hearts from NZB/W F1 mice receiving B19-VP1u IgG. However, no significant variation of cardiac atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), heart-type fatty acid-binding protein (h-FABP) and creatine kinase MB (CK-MB) were detected among all experimental groups. These findings firstly demonstrated the aggravated effects of anti-B19 VP1u IgG on cardiac injury by induction of inflammatory but not myocardial infarction-associated proteins through activation of phosphorylated p-38 and NF-κB signaling.

Selfness-nonselfness in designing an anti-B19 erythrovirus vaccine

Although B19 erythrovirus infection may be associated with severe clinical outcomes, especially in early infancy, pregnancy and in immunocompromised or hemolytic subjects, no vaccine is currently available. Using the concept that effective immune responses to an infectious agent may be restricted to the specific peptidome unique to that agent, we analyzed primary amino acid sequence of B19 erythrovirus, searching for peptide motifs to be used in vaccine formulations. Here, we identify and describe a set of unique viral peptides that may guarantee both high efficacy and practically no cross-reactive autoimmune responses in anti-B19 immunotherapeutic approaches.