Enhanced expression of the soluble form of E-selectin attenuates progression of lupus nephritis and vasculitis in MRL/lpr mice

Endothelial Dysfunction: Molecular Mechanisms and Therapeutic Strategies in Kawasaki Disease

The endothelium plays a key role in regulating vascular homeostasis by responding to a large spectrum of chemical and physical stimuli. Vasculitis is a group of inflammatory conditions affecting the vascular bed, and it is known that they are strongly linked to endothelial dysfunction (ED). Kawasaki disease (KD) is one childhood systemic vasculitis, and it represents the leading cause of acquired cardiac disease in children due to coronary damage and subsequent cardiovascular (CV) morbidity and mortality. We aimed to focus on the actual knowledge of ED in the pathogenesis of KD and its practical implications on therapeutical strategies to limit cardiovascular complications. Understanding ED in KD provides insight into the underlying mechanisms and identifies potential therapeutic targets to mitigate vascular damage, ultimately improving cardiovascular outcomes in both the acute and chronic stages of the disease. However, research gaps remain, particularly in translating findings from animal models into clinical applications for cardiovascular lesions and related morbidity in KD patients.

Systemic autoimmune abnormalities alter the morphology of mucosa-associated lymphoid tissues in the rectum of MRL/MpJ-Faslpr/lpr mice

Systemic autoimmune diseases (ADs) might affect the morphology and function of gut-associated lymphoid tissue (LTs) indirectly; however, their exact relationship remains unclear. Therefore, we investigated mouse LTs in the anorectal canal and morphologically compared them between MRL/MpJ-Fas+/+ and MRL/MpJ-Faslpr/lpr mice. LT aggregations, also known as rectal mucosa-associated lymphoid tissues (RMALTs), were exclusively seen in the lamina propria and submucosa of the rectum. The mean size and number of the LT aggregations both significantly increased in MRL/MpJ-Faslpr/lpr mice compared to those in MRL/MpJ-Fas+/+ mice. The distance from the anorectal junction to the first LT aggregate was significantly shorter in MRL/MpJ-Faslpr/lpr mice than that in MRL/MpJ-Fas+/+ mice. Immunostaining revealed that the RMALTs included CD3+, CD4+, and CD8+ T cells; B220+ B cells; IBA1+ macrophages; Ki67+ proliferative cells; and PNAd+ high-endothelial venules (HEVs). The numbers of macrophages, proliferative cells, CD4+ T cells, CD8+ T cells, and HEVs were significantly increased in MRL/MpJ-Faslpr/lpr mice compared to those in MRL/MpJ mice. Furthermore, the gene expression levels of chemokines (Cxcl9 and Cxcl13) and their corresponding receptors (Cxcr3 and Cxcr5) were significantly higher in MRL/MpJ-Faslpr/lpr mice than those in MRL/MpJ-Fas+/+ mice. Although the morphology of rectal epithelium was comparable between the strains, M cell number was significantly higher in MRL/MpJ-Faslpr/lpr mice than in MRL/MpJ-Fas+/+ mice. Thus, ADs could alter RMALT morphology, and quantitative changes in T-cell subsets, proliferative cells, macrophages, HEVs, chemokine expression, and M cells could affect their cell composition and development.

Identification of Specific Biomarkers and Pathways in the Treatment Response of Infliximab for Inflammatory Bowel Disease: In-Silico Analysis

Background: Inflammatory bowel disease (IBD) is characterized by chronic inflammation of the gastrointestinal tract. In biological therapy, infliximab became the first anti-tumor necrosis factor (TNF) agent approved for IBD. Despite this success, infliximab is expensive, often ineffective, and associated with adverse events. Prediction of infliximab resistance would improve overall potential outcomes. Therefore, there is a pressing need to widen the scope of investigating the role of genetics in IBD to their association with therapy response. Methods: In the current study, an in-silico analysis of publicly available IBD patient transcriptomics datasets from Gene Expression Omnibus (GEO) are used to identify subsets of differentially expressed genes (DEGs) involved in the pathogenesis of IBD and may serve as potential biomarkers for Infliximab response. Five datasets were found that met the inclusion criteria. The DEGs for datasets were identified using limma R packages through the GEOR2 tool. The probes’ annotated genes in each dataset intersected with DGEs from all other datasets. Enriched gene Ontology Clustering for the identified genes was performed using Metascape to explore the possible connections or interactions between the genes. Results: 174 DEGs between IBD and healthy controls were found from analyzing two datasets (GSE14580 and GSE73661), indicating a possible role in the pathogenesis of IBD. Of the 174 DEGs, five genes (SELE, TREM1, AQP9, FPR2, and HCAR3) were shared between all five datasets. Moreover, these five genes were identified as downregulated in the infliximab responder group compared to the non-responder group. Conclusions: We hypothesize that alteration in the expression of these genes leads to an impaired response to infliximab in IBD patients. Thus, these genes can serve as potential biomarkers for the early detection of compromised infliximab response in IBD patients.

Silica Induction of Diverse Inflammatory Proteome in Lungs of Lupus-Prone Mice Quelled by Dietary Docosahexaenoic Acid Supplementation

Repeated short-term intranasal instillation of lupus-prone mice with crystalline silica (cSiO2) induces inflammatory gene expression and ectopic lymphoid neogenesis in the lung, leading to early onset of systemic autoimmunity and rapid progression to glomerulonephritis. These responses are suppressed by dietary supplementation with the ω-3 polyunsaturated fatty acid docosahexaenoic acid (DHA). Here, we tested the hypothesis that dietary DHA supplementation suppresses cSiO2-induced inflammatory proteins in bronchoalveolar alveolar lavage fluid (BALF) and plasma of lupus-prone mice. Archived tissue fluid samples were used from a prior investigation in which 6 wk-old lupus-prone female NZBWF1 mice were fed isocaloric diets containing 0 or 10 g/kg DHA for 2 wks and then intranasally instilled with 1 mg cSiO2 or vehicle once weekly for 4 wks. Cohorts were terminated at 1, 5, 9 or 13 wk post-instillation (PI). BALF and plasma from each cohort were analyzed by high density multiplex array profiling of 200 inflammatory proteins. cSiO2 time-dependently induced increases in the BALF protein signatures that were highly reflective of unresolved lung inflammation, although responses in the plasma were much less robust. Induced proteins in BALF included chemokines (e.g., MIP-2, MCP-5), enzymes (e.g., MMP-10, granzyme B), adhesion molecules (e.g., sE-selectin, sVCAM-1), co-stimulatory molecules (e.g., sCD40L, sCD48), TNF superfamily proteins (e.g., sTNFRI, sBAFF-R), growth factors (e.g., IGF-1, IGFBP-3), and signal transduction proteins (e.g., MFG-E8, FcgRIIB), many of which were blocked or delayed by DHA supplementation. The BALF inflammatory proteome correlated positively with prior measurements of gene expression, pulmonary ectopic lymphoid tissue neogenesis, and induction of autoantibodies in the lungs of the control and treatment groups. Ingenuity Pathway Analysis (IPA) revealed that IL-1β, TNF-α, and IL-6 were among the top upstream regulators of the cSiO2-induced protein response. Furthermore, DHA's effects were associated with downregulation of cSiO2-induced pathways involving i) inhibition of ARE-mediated mRNA decay, ii) bacterial and viral pattern recognition receptor activation, or iii) TREM1, STAT3, NF-κB, and VEGF signaling and with upregulation of PPAR, LXR/RXR and PPARα/RXRα signaling. Altogether, these preclinical findings further support the contention that dietary DHA supplementation could be applicable as an intervention against inflammation-driven autoimmune triggering by cSiO2 or potentially other environmental agents.

CD8+CD103+ iTregs inhibit the progression of lupus nephritis by attenuating glomerular endothelial cell injury

OBJECTIVES

We previously reported that ex vivo TGF-β and IL-2-induced CD8+CD103+ regulatory T cells (CD8+CD103+ iTregs) displayed similar immunosuppressive effect and therapeutic function on lupus mice nephritis to that of CD4+Foxp3+ Tregs. In view of the important role of glomerular endothelial cell (GEC) injury in inflammatory processes in SLE, this study aimed to investigate the nature and mechanism of CD8+CD103+ iTregs-mediated amelioration of LN by attenuating GEC injury.

METHODS

Treg cells from patients with SLE and from healthy controls were characterized by flow cytometry analysis. The expression of pro-inflammatory mediators and VEGF were analysed in healthy controls, patients with SLE and MRL/lpr mice by ELISA, western blot, and real-time quantitative RT-PCR (qRT-PCR). Typical lesions of diffuse proliferative LN were observed in MRL/lpr mice through the use of haematoxylin and eosin, Masson, periodic acid-Schiff, periodic acid-Schiff methenamine, transmission electron microscopy and IF microscopy. Angiogenesis was analysed in GECs by cell investigating proliferation, migration, and tube formation.

RESULTS

The results revealed that the frequency of Treg cells was inversely correlated with the expression of VCAM-1 and ICAM-1 in patients with SLE. Furthermore, adoptive transfer of CD8+CD103+ iTregs to MRL/lpr mice was associated with decreased levels of autoantibodies and proteinuria, reduced renal pathological lesions, and lowered renal deposition of IgG/C3. We further found that CD8+CD103+ iTregs not only suppressed the expression of pro-inflammatory mediators but also attenuated GEC injury by promoting angiogenesis.

CONCLUSION

Our study has identified the role of CD8+CD103+ iTregs on attenuating GEC injury and provided a possible application of this new iTregs subset in lupus nephritis and other autoimmune diseases.

In silico Analyses of Skin and Peripheral Blood Transcriptional Data in Cutaneous Lupus Reveals CCR2-A Novel Potential Therapeutic Target

Cutaneous lesions feature prominently in lupus erythematosus (LE). Yet lupus and its cutaneous manifestations exhibit extraordinary clinical heterogeneity, making it imperative to stratify patients with varying organ involvement based on molecular criteria that may be of clinical value. We conducted several in silico bioinformatics-based analyses integrating chronic cutaneous lupus erythematosus (CCLE)-skin and blood expression profiles to provide novel insights into disease mechanisms and potential future therapy. In addition to substantiating well-known prominent apoptosis and interferon related response in both tissue environments, the overrepresentation of GO categories in the datasets, in the context of existing literature, led us to model a “disease road-map” demonstrating a coordinated orchestration of the autoimmune response in CCLE reflected in three phases: (1) initiation, (2) amplification, and (3) target damage in skin. Within this framework, we undertook in silico interactome analyses to identify significantly “over-connected” genes that are potential key functional players in the metabolic reprogramming associated with skin pathology in CCLE. Furthermore, overlapping and distinct transcriptional “hot spots” within CCLE skin and blood expression profiles mapping to specified chromosomal locations offer selected targets for identifying disease-risk genes. Lastly, we used a novel in silico approach to prioritize the receptor protein CCR2, whose expression level in CCLE tissues was validated by qPCR analysis, and suggest it as a drug target for use in future potential CCLE therapy.

CD8+iTregs attenuate glomerular endothelial cell injury in lupus-prone mice through blocking the activation of p38 MAPK and NF-κB

Systemic lupus erythematosus (SLE) is a chronic inflammatory disease. Endothelial cell injury plays an important role in the inflammatory processes associated with SLE. CD4+Foxp3+regulatory T cells (Tregs) reduce the injury to endothelial cells induced by inflammatory factors. As a newly identified regulatory T cell, we previously reported that CD8+CD103+iTregs had similar effects to those of CD4+iTregs in the process of immunoregulation. In this paper, we further explored the effect and mechanism of CD8+iTregs on endothelial cell injury. The expressions of vascular cellular adhesion molecule-1 (VCAM-1), intracellular adhesion molecule-1 (ICAM-1), interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1) in MRL/lpr mouse glomerular endothelial cells (lupus-MGECs) were estimated by quantitative real-time polymerase chain reaction, enzyme-linked immunosorbent assay and Western blotting. The lupus-MGEC apoptosis rate was detected by flow cytometry and the adhesion of monocyte-like cells to lupus-MGECs exposed to lipopolysaccharide (LPS) was determined by the adhesion assay. Additionally, the expressions of P-p38, P-NF-κB and P-IκBα were detected by Western blotting. The results showed that LPS increased the expressions of VCAM-1, ICAM-1, IFN-γ, TNF-α, IL-6 and MCP-1 in lupus-MGECs, while CD8+iTregs significantly decreased the levels of these adhesion molecules and inflammatory mediators. Furthermore, CD8+iTregs alleviated lupus-MGEC apoptosis and inhibited the adhesion of monocyte-like cells to lupus-MGECs. Both nuclear factor-κB (NF-κB) and p38 mitogen-activated protein kinase (MAPK), activated by LPS, were suppressed by CD8+iTregs. These findings suggest that CD8+iTregs attenuate LPS-induced glomerular endothelial cell injury through blocking the activation of p38 MAPK and NF-κB in lupus-MGECs. The protective effect of CD8+iTregs indicates their possible therapeutic application in Lupus nephritis.

Association between E-selectin expression and histopathological modification of glomerular lesions by non-nephritogenic IgM antibodies in experimental lupus nephritis

OBJECTIVE

To examine the role played by E-selectin in bystander IgM-mediated modification of glomerular lesions in experimental lupus nephritis.

METHODS

Experimental lupus SCID mice were induced by an intraperitoneal injection of clone 7B6.8, which was derived from a MRL/lpr mouse and shown to induce wire-loop type glomerular lesions. Mice were subsequently administered clone Sp6, a non-nephritogenic IgM antibody- producing hybridoma. E-selectin expression was then evaluated in glomeruli showing histopathological conversion of lesions from wire-loop-like to a cell-proliferative form. We also investigated the effects of a circulating soluble form of E-selectin (sE-selectin) on the modification of glomerular lesions in this lupus model.

RESULTS

In experimental lupus mice, glomerular E-selectin expression significantly increased during the conversion from wire-loop-like glomerular lesions to a cell-proliferative type mediated by a non-nephritogenic bystander IgM antibody in presence of a nephritogenic antibody. Intraglomerular infiltration of CD68 + macrophages correlated significantly with the glomerular level of E-selectin expression. In addition, overexpression of circulating sE-selectin significantly suppressed conversion to cell-proliferative glomerular lesions and glomerular macrophage infiltration in these lupus model mice.

CONCLUSIONS

The histopathological modification of lupus nephritis by non-nephritogenic bystander IgM antibodies is associated in part with glomerular E-selectin expression.