Th17-related cytokines in systemic lupus erythematosus patients with dilated cardiomyopathies: a possible linkage to parvovirus B19 infection

Roles of Sphingosine Kinase and Sphingosine-1-Phosphate Receptor 2 in Endotoxin-Induced Acute Retinal Inflammation

PURPOSE

To investigate the roles of sphingosine kinases (SphKs) and sphingosine-1-phosphate receptors (S1PRs) in endotoxin-induced uveitis (EIU) mice.

METHODS

EIU model was induced using an intraperitoneal injection of lipopolysaccharide (LPS). The expression of SphKs and S1PRs in the retina was assessed using quantitative polymerase chain reaction (qPCR) and immunofluorescence. The effects of S1PR antagonists on the expression of inflammatory cytokines in the retina were evaluated using qPCR and western blotting. Effects of leukocyte infiltration of the retinal vessels were evaluated to determine the effects of the S1PR2 antagonist and genetic deletion of S1PR2 on retinal inflammation.

RESULTS

Retinal SphK1 expression was significantly upregulated in EIU. SphK1 was expressed in the GCL, IPL, and OPL and S1PR2 was expressed in the GCL, INL, and OPL. Positive cells in IPL and OPL of EIU retina were identified as endothelial cells. S1PR2 antagonist and genetic deletion of S1PR2 significantly suppressed the expression of IL-1α, IL-6, TNF-α, and ICAM-1, whereas S1PR1/3 antagonist did not. Use of S1PR2 antagonist and S1PR2 knockout in mice significantly ameliorated leukocyte adhesion induced by LPS.

CONCLUSION

SphK1/S1P/S1PR2 signaling was upregulated in EIU and S1PR2 inhibition suppressed inflammatory response. Targeting this signaling pathway has potential for treating retinal inflammatory diseases.

Viral Infection in Endometritis: Is There an Important Role or Not?

Chronic endometritis (CE) is a frequent pathological condition that is defined as localized inflammation in the endometrium. Some adverse fertility consequences such as recurrent miscarriage and failure of implantation are associated with chronic endometritis. On the one hand, inflammation plays an important role in the pathogenesis of endometritis, and on the other hand, the role of viral infections in inducing inflammation can make this review strongly attractive and practical. We set out to provide an overview of viral infections as a potential etiology of CE pathophysiology through the alteration of an endometrial microenvironment and its association with infertility. To the best of our knowledge, this is the first review to demonstrate the role of viral infection in chronic endometritis, and whether or not infection ultimately plays a role..

Parvovirus B19 in Rheumatic Diseases

Parvovirus B19 (B19V) is a human pathogen belonging to the Parvoviridae family. It is widely diffused in the population and responsible for a wide range of diseases, diverse in pathogenetic mechanisms, clinical course, and severity. B19V infects and replicates in erythroid progenitor cells (EPCs) in the bone marrow leading to their apoptosis. Moreover, it can also infect, in an abortive manner, a wide set of different cell types, normally non-permissive, and modify their normal physiology. Differences in the characteristics of virus-cell interaction may translate into different pathogenetic mechanisms and clinical outcomes. Joint involvement is a typical manifestation of B19V infection in adults. Moreover, several reports suggest, that B19V could be involved in the pathogenesis of some autoimmune rheumatologic diseases such as rheumatoid arthritis (RA), juvenile idiopathic arthritis (JIA), systemic sclerosis (SSc), systemic lupus erythematosus (SLE), or vasculitis. This review provides basic information on the B19 virus, highlights characteristics of viral infection in permissive and non-permissive systems, and focuses on recent findings concerning the pathogenic role of B19V in rheumatologic diseases.

Celastrol attenuates human parvovirus B19 NS1‑induced NLRP3 inflammasome activation in macrophages

Human parvovirus B19 (B19V) has been strongly associated with a variety of inflammatory disorders, such as rheumatoid arthritis (RA), inflammatory bowel disease and systemic lupus erythematosus. Non‑structural protein 1 (NS1) of B19V has been demonstrated to play essential roles in the pathological processes of B19V infection due to its regulatory properties on inflammatory cytokines. Celastrol, a quinone methide isolated from Tripterygium wilfordii, has displayed substantial potential in treating inflammatory diseases, such as psoriasis and RA. However, little is known about the effects of celastrol on B19V NS1‑induced inflammation. Therefore, cell viability assay, migration assay, phagocytosis analysis, zymography assay, ELISA and immunoblotting were conducted to verify the influences of celastrol on macrophages. The present study reported the attenuating effects of celastrol on B19V NS1‑induced inflammatory responses in macrophages derived from human acute monocytic leukemia cell lines, U937 and THP‑1. Although the migration was not significantly decreased by celastrol in both U937 and THP‑1 macrophages, significantly decreased viability, migration and phagocytosis were detected in both B19V NS1‑activated U937 and THP‑1 macrophages in the presence of celastrol. Additionally, celastrol significantly decreased MMP‑9 activity and the levels of inflammatory cytokines, including IL‑6, TNF‑α and IL‑1β, in B19V NS1‑activated U937 and THP‑1 cells. Notably, significantly decreased levels of NLR family pyrin domain‑containing 3, apoptosis‑associated speck‑like, caspase‑1 and IL‑18 proteins were observed in both B19V NS1‑activated U937 and THP‑1 cells in the presence of celastrol, indicating the involvement of the inflammasome pathway. To the best of our knowledge, the present study is the first to report on the attenuating effects of celastrol on B19V NS1‑induced inflammatory responses in macrophages, suggesting a therapeutic role for celastrol in B19V NS1‑related inflammatory diseases.

Effect of N‑terminal region of human parvovirus B19‑VP1 unique region on cardiac injury in naïve mice

A unique region of human parvovirus B19 virus-VP1 (B19V–VP1u) has been linked to a variety of cardiac disorders. However, the precise role of B19V–VP1u in inducing cardiac injury remains unknown. The present study investigated the effects of B19V–VP1u and different regions of B19V–VP1u, including B19V–VP1uA (residues 1–60), B19V–VP1uB (residues 61–129), B19V–VP1uC (residues 130–195) and B19V–VP1uD (residues 196–227), on inducing cardiac injury in naïve mice by zymography, immunoblotting, H&E staining and cytokine immunoassay. A significantly higher MMP-9/MMP-2 ratio and increased levels of inflammatory cytokines, including IL-6 and IL-1β, were detected in the left ventricles of the mice injected with B19V-non-structural protein 1 (B19V-NS1) and B19V–VP1u, accompanied by increased expression levels of phosphorylated (p-)ERK and p-P38. Significantly upregulated expression levels of atrial natriuretic peptide (ANP), heart-type fatty acid-binding protein (H-FABP) and creatine kinase isoenzyme-MB (CK-MB), which are well-known cardiac injury markers, as well as increased infiltration of lymphocytes, were detected in the left ventricles of the mice injected with B19V–VP1, B19V-NS1 and B19V–VP1u. Moreover, a significantly higher MMP-9/MMP-2 ratio and increased levels of IL-6 and IL-1β were observed in the left ventricles of the mice injected with B19V–VP1u, B19V–VP1u-A, B19V–VP1u-B and B19V–VP1u-C, accompanied by upregulated p-ERK and p-P38 expression. Notably, significantly lower levels of IL-6 and IL-1β were observed in the left ventricles of the mice injected with B19V–VP1uD. Furthermore, significantly increased ANP, H-FABP and CK-MB expression levels were detected in the left ventricles of the mice injected with B19V–VP1u, B19V–VP1u-A and B19V–VP1u-B, along with enhanced infiltration of lymphocytes. Significantly higher serum IL-1β, IL-6, TNF-α and IFN-γ levels were also detected in the mice injected with B19V–VP1u, B19V–VP1u-A and B19V–VP1u-B. To the best of our knowledge, the findings of the present study were the first to demonstrate that the N-terminal region (residues 1–129) of B19V–VP1u induces an increase in the levels of cardiac injury markers, thus providing evidence for understanding the possible functional regions within B19V–VP1u.

Viral Infections and Systemic Lupus Erythematosus: New Players in an Old Story

A causal link between viral infections and autoimmunity has been studied for a long time and the role of some viruses in the induction or exacerbation of systemic lupus erythematosus (SLE) in genetically predisposed patients has been proved. The strength of the association between different viral agents and SLE is variable. Epstein-Barr virus (EBV), parvovirus B19 (B19V), and human endogenous retroviruses (HERVs) are involved in SLE pathogenesis, whereas other viruses such as Cytomegalovirus (CMV) probably play a less prominent role. However, the mechanisms of viral-host interactions and the impact of viruses on disease course have yet to be elucidated. In addition to classical mechanisms of viral-triggered autoimmunity, such as molecular mimicry and epitope spreading, there has been a growing appreciation of the role of direct activation of innate response by viral nucleic acids and epigenetic modulation of interferon-related immune response. The latter is especially important for HERVs, which may represent the molecular link between environmental triggers and critical immune genes. Virus-specific proteins modulating interaction with the host immune system have been characterized especially for Epstein-Barr virus and explain immune evasion, persistent infection and self-reactive B-cell "immortalization". Knowledge has also been expanding on key viral proteins of B19-V and CMV and their possible association with specific phenotypes such as antiphospholipid syndrome. This progress may pave the way to new therapeutic perspectives, including the use of known or new antiviral drugs, postviral immune response modulation and innate immunity inhibition. We herein describe the state-of-the-art knowledge on the role of viral infections in SLE, with a focus on their mechanisms of action and potential therapeutic targets.

The role of Th17 cells in viral infections

The present review provides an overview of recent advances regarding the function of Th17 cells and their produced cytokines in the progression of viral diseases. Viral infections alone do not lead to virus-induced malignancies, as both genetic and host safety factors are also involved in the occurrence of malignancies. Acquired immune responses, through the differentiation of Th17 cells, form the novel components of the Th17 cell pathway when reacting with viral infections all the way from the beginning to its final stages. As a result, instead of inducing the right immune responses, these events lead to the suppression of the immune system. In fact, the responses from Th17 cells during persistent viral infections causes chronic inflammation through the production of IL-17 and other cytokines which provide a favorable environment for tumor growth and its development. Additionally, during the past decade, these cells have been understood to be involved in tumor progression and metastasis. However, further research is required to understand Th17 cells' immune mechanisms in the vast variety of viral diseases. This review aims to determine the roles and effects of the immune system, especially Th17 cells, in the progression of viral diseases; which can be highly beneficial for the diagnosis and treatment of these infections.

Simultaneous Presentation of Parvovirus B19 Infection and Systemic Lupus Erythematosus in a Patient: Description and Review of the Literature

We present the case of a 25-year-old woman without medical history, presenting with acute respiratory failure needing mechanical ventilation. Aetiologic screening showed PVB19 primary infection and concomitant SLE flare-up. We discuss the causative interactions between PVB19 and SLE in the pathogenesis of the disease. Difficulty diagnosing inaugural SLE flare-up concomitant with PVB19 infection can lead to delayed diagnosis and treatment. Inversely, overtreating a SLE-mimicking PVB19 infection with immunosuppressive agents can be highly detrimental.

The effects of human parvovirus VP1 unique region in a mouse model of allergic asthma

Evidence has indicated that viral infection increases the risk of developing asthma. Although the association of human parvovirus B19 (B19V) or human bocavirus (HBoV) with respiratory diseases has been reported, little is known about the influence of the B19V-VP1u and HBoV-VP1u proteins on the symptoms of asthma. Herein, we investigated the systemic influence of subcutaneously injected B19V-VP1u and HBoV-VP1u recombinant proteins in an OVA-sensitized asthmatic mouse model. A significantly higher Penh ratio and IgE level were detected in the serum, bronchoalveolar lavage fluid (BALF) and the supernatant of a lymphocyte culture from mice treated with HBoV-VP1u or B19V-VP1u than in a lymphocyte culture from OVA-sensitized mice. Significantly higher levels of serum and BALF IgE, total IgG, IgG1, OVA-specific IgE and OVA-specific IgG1 were detected in mice treated with HBoV-VP1u or B19V-VP1u than in OVA-sensitized mice. Conversely, a significantly lower IgG2a level was detected in mice from the HBoV-VP1u or B19V-VP1u groups than in mice from the OVA group. The mice treated with HBoV-VP1u or B19V-VP1u exhibited more significant lung inflammatory indices, including elevated serum and BALF IL-4, IL-5, IL-10 and IL-13 levels; BALF lymphocyte, neutrophil and eosinophil counts, MMP-9 and MMP-2 activity; and the amount of lymphocyte infiltration, relative to those in the control mice or in those sensitized with OVA. These findings demonstrate that the subcutaneous injection of HBoV-VP1u or B19V-VP1u proteins in OVA-sensitized mice result in elevated asthmatic indices and suggest that human parvoviruses may increase the risk of developing airway inflammation in a mouse model of asthma.

Effects of Th17 cells and IL-17 in the progression of cervical carcinogenesis with high-risk human papillomavirus infection

The existence of Th17 cells and IL‐17 was recently shown in several types of infectious diseases, but their distribution and functions in cervical lesions with high‐risk human papillomavirus (HPV) infection have not been fully elucidated. In this study, the frequency of Th17 cells in peripheral blood samples obtained from 28 cervical squamous cell carcinoma patients, 26 CIN1 patients, 30 CIN2 patients, 29 CIN3 patients, 25 high‐risk HPV‐infected women with normal cervical cytology, and 30 healthy controls was determined by flow cytometry. Besides, the levels of IL‐17 in peripheral blood samples as well as in supernatant of cervical tissue homogenate were assessed by enzyme‐linked immunosorbent assay (ELISA) simultaneously. We found that during the disease progression of cervical lesions, the proportion of Th17 cells in the total CD4⁺ cells showed a gradually increased tendency compared with the controls (P < 0.05). Moreover, levels of IL‐17 in serum and supernatant of cervical tissue homogenate showed the same tendency as the proportion of Th17 cells (P < 0.05). When compared in pairs, the levels of IL‐17 in supernatant differed significantly among the study groups and the control group (P < 0.05), but no significant difference was observed in serum (P > 0.05). In conclusions, the results indicate that Th17 cells and IL‐17 may play a role of immune enhancement in the infection of high‐risk HPV especially in the cervical microenvironment, which contribute to the disease progression of its associated cervical lesions.

Suppression of interleukin 17 contributes to the immunomodulatory effects of adipose-derived stem cells in a murine model of systemic lupus erythematosus

Due to roles in immunoregulation and low immunogenicity, mesenchymal stem cells have been suggested to be potent regulators of the immune response and may represent promising treatments for autoimmune disease. Adipose-derived stem cells (ADSCs), stromal cells derived from adipose tissue, were investigated with allogeneic ADSCs in B6.MRL/lpr mice, a murine model of systemic lupus erythematosus (SLE). We intravenously injected allogeneic ADSCs into SLE mice after disease onset and report that ADSCs reduced anti-ds DNA antibodies in serum and proteinuria in SLE mice. Also, ADSCs decreased IL-17 and IL-6 expression in serum of SLE mice. ADSCs alleviated renal damage and inflammatory cell infiltration and edema of the renal interstitium. Furthermore, ADSCs significantly downregulated renal IL-17 and CD68 expression, suggesting that ADSCs suppressed renal inflammation. ADSCs also decreased IL-17 mRNA expression and increased Foxp3, ROR-γt and miR-23b mRNA expression in renal tissue in SLE mice. ADSCs reduced renal protein expression of TAB 2 and IKK-α in SLE mice. Thus, ADSCs may be a novel potential therapy for treating SLE.

Systemic autoimmunity induced by the TLR7/8 agonist Resiquimod causes myocarditis and dilated cardiomyopathy in a new mouse model of autoimmune heart disease

Systemic autoimmune diseases such as systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) show significant heart involvement and cardiovascular morbidity, which can be due to systemically increased levels of inflammation or direct autoreactivity targeting cardiac tissue. Despite high clinical relevance, cardiac damage secondary to systemic autoimmunity lacks inducible rodent models. Here, we characterise immune-mediated cardiac tissue damage in a new model of SLE induced by topical application of the Toll-like receptor 7/8 (TLR7/8) agonist Resiquimod. We observe a cardiac phenotype reminiscent of autoimmune-mediated dilated cardiomyopathy, and identify auto-antibodies as major contributors to cardiac tissue damage. Resiquimod-induced heart disease is a highly relevant mouse model for mechanistic and therapeutic studies aiming to protect the heart during autoimmunity.

Summary: A novel mouse model of autoimmune-mediated heart damage to study the underlying mechanisms and test therapeutic options for systemic autoimmunity.

Efficiency of immunosuppressive therapy in virus-negative and virus-positive patients with morphologically verified lymphocytic myocarditis

Aim. To evaluate the efficiency of immunosuppressive therapy (IST) in virus-negative (V–) and virus-positive (V+) patients with lymphocytic myocarditis (LM). Subjects and methods. 60 patients (45 males) (mean age 46.7±11.8 years) with dilated cardiomyopathy (mean left ventricular (LV) end diastolic size (EDS) 6.7±0.7 cm; ejection fraction (EF) 26.2±9.1%) were examined. The diagnosis of active/borderline LM was verified by right ventricular endomyocardial biopsy in 38 patients, by intraoperative LV biopsy in 10, in the study of explanted hearts from 3 patients and at autopsy in 9. The investigators determined the genomes of parvovirus B19, herpes viruses types 1, 2 and 6, Epstein—Barr (EBV), zoster, and cytomegalovirus in the blood and myocardium and, if antibodies were present in the blood, hepatitis B and C viruses, as well as antibodies against antigens in the endothelium, cardiomyocytes and their nuclei, smooth muscles, fibers of the conducting system. IST was used in terms of histological, immune, and viral activities. IST was performed in 22 V+ patients (Group 1) and in 24 V– patients (Group 2); this was not done in 10 V+ patients (Group 3) and V– patients (Group 4). IST comprised methylprednisolone at a mean dose of 24 mg/day (n=40), hydroxychloroquine 200 mg/day (n=20), azathioprine at a mean dose of 150 mg/day (n=21); antiviral therapy included acyclovir, ganciclovir, intravenous immunoglobulin (n=24). The follow-up period was 19 (7.3—40.3) months. Results. The viral genome was detected in the myocardium of 32 patients who made up a V+ group. The degree of histological activity did not differ in relation to the presence of viral genome in the myocardium. The degree of immune activity (anticardiolipin antibody titers) in the V+ patients was as high as that in V– ones. At baseline, the V+ patients had a significantly higher LV EDS and a lower EF than the V– patients. Overall, IST only could lead to a significant increase in EF (from 26.5±0.9 to 36.0±10.8%; p

Associations between Interleukin-31 Gene Polymorphisms and Dilated Cardiomyopathy in a Chinese Population

To explore the role of Interkeulin-31 (IL-31) in dilated cardiomyopathy (DCM), in our study, two SNPs of IL-31, rs4758680 (C/A) and rs7977932 (C/G), were analyzed in 331 DCM patients and 493 controls in a Chinese Han population. The frequencies of C allele and CC genotype of rs4758680 were significantly increased in DCM patients (P = 0.005, P = 0.001, resp.). Compared to CC genotype of rs4758680, the A carriers (CA/AA genotypes) were the protect factors in DCM susceptibility while the frequencies of CA/AA genotypes were decreased in the dominant model for DCM group (P < 0.001, OR = 0.56, 95%CI = 0.39–0.79). Moreover, IL-31 mRNA expression level of white blood cells was increased in DCM patients (0.072 (0.044–0.144) versus 0.036 (0.020–0.052), P < 0.001). In survival analysis of 159 DCM patients, Kaplan-Meier curve revealed the correlation between CC homozygote of rs4758680 and worse prognosis for DCM group (P = 0.005). Compared to CC genotype, the CA/AA genotypes were the independent factors in both univariate (HR = 0.530, 95%CI = 0.337–0.834, P = 0.006) and multivariate analyses after age, gender, left ventricular end-diastolic diameter, and left ventricular ejection fraction adjusted (HR = 0.548, 95%CI = 0.345–0.869, P = 0.011). Thus, we concluded that IL-31 gene polymorphisms were tightly associated with DCM susceptibility and contributed to worse prognosis in DCM patients.

Human Parvoviruses

Parvovirus B19 (B19V) and human bocavirus 1 (HBoV1), members of the large Parvoviridae family, are human pathogens responsible for a variety of diseases. For B19V in particular, host features determine disease manifestations. These viruses are prevalent worldwide and are culturable in vitro, and serological and molecular assays are available but require careful interpretation of results. Additional human parvoviruses, including HBoV2 to -4, human parvovirus 4 (PARV4), and human bufavirus (BuV) are also reviewed. The full spectrum of parvovirus disease in humans has yet to be established. Candidate recombinant B19V vaccines have been developed but may not be commercially feasible. We review relevant features of the molecular and cellular biology of these viruses, and the human immune response that they elicit, which have allowed a deep understanding of pathophysiology.