DNA-histone complexes as ligands amplify cell penetration and nuclear targeting of anti-DNA antibodies via energy-independent mechanisms

Anti-DNA antibody-targeted D-peptide nanoparticles ameliorate lupus nephritis in MRL/lpr mice

Peptide ALW (ALWPPNLHAWVP) targeting anti-dsDNA antibodies has shown promising therapeutic effects in alleviating lupus nephritis, but is potentially limited by poor stability and non-kidney targeting. We recently developed a D-form modified ALW, called D-ALW, which has the capacity to widely inhibit pathogenic polyclonal anti-dsDNA antibody reactions. Further modification of D-ALW using PEG-PLGA nanoparticles to enhance good kidney-targeting ability and extend half-life. Here, we demonstrate that the D-form modified ALW maintains higher binding and inhibition efficiencies and achieves higher stability. Most importantly, D-ALW nanoparticles exhibit excellent kidney-targeting ability and prolong the half-life of the peptides in BALB/c mice. Additionally, compared to D-ALW, D-ALW nanoparticles significantly reduce the glomerular deposition of IgG and C3, improve renal histopathologies, such as glomerular proliferation and inflammatory cells infiltration, and markedly prolong lifespan in MRL/lpr lupus-prone mice. Overall, these results establish that the D-ALW nanoparticles offer synergistic benefits in both safety and efficacy, providing long-term renal preservation and treatment advantages in lupus nephritis.

An Emerging Role for Anti-DNA Antibodies in Systemic Lupus Erythematosus

Anti-DNA antibodies are hallmark autoantibodies produced in systemic lupus erythematosus (SLE), but their pathogenetic role is not fully understood. Accumulating evidence suggests that some anti-DNA antibodies enter different types of live cells and affect the pathophysiology of SLE by stimulating or impairing these cells. Circulating neutrophils in SLE are activated by a type I interferon or other stimuli and are primed to release neutrophil extracellular traps (NETs) on additional stimulation. Anti-DNA antibodies are also involved in this process and may induce NET release. Thereafter, they bind and protect extracellular DNA in the NETs from digestion by nucleases, resulting in increased NET immunogenicity. This review discusses the pathogenetic role of anti-DNA antibodies in SLE, mainly focusing on recent progress in the two research fields concerning antibody penetration into live cells and NETosis.

An update on cell-penetrating peptides with intracellular organelle targeting

INTRODUCTION

Cell-penetrating peptide (CPP) technologies represent an important strategy to address drug delivery to specific intracellular compartments by covalent conjugation to targeting sequences, potentially enabling strategies to combat most diseases.

AREAS COVERED

This updated review article provides an overview of current intracellular organelle targeting by CPP. The targeting strategies of CPP and CPP/cargo complexes to specific cells or intracellular organelles are summarized, and the review provides an update on the current data for their pharmacological and therapeutical applications.

EXPERT OPINION

Targeted drug delivery is moving from the level of tissue or specific pathogenic cell to the level of specific organelle that is the target of the drug, an important aspect in drug design and development. Organelle-targeted drug delivery results in improved efficacy, ability to control mode of action, reduction of undesired toxicities and side effects, and possibility to overcome drug resistance mechanisms.

The Therapeutic Strategies for SLE by Targeting Anti-dsDNA Antibodies

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by diverse serological autoantibodies. Anti-dsDNA antibodies are involved in multiple organ damage, especially the kidney, skin, and central nervous system. Anti-dsDNA antibodies play a pivotal role in SLE, and researchers have developed therapeutic strategies targeting these antibodies. Approaches to reduce anti-dsDNA antibodies via B cell targeted biologics against B cell surface antigens, B cell survival factors, or Bruton's tyrosine kinase have effectively eliminated B cells. However, their non-specific depletion hampers normal immune system functioning and limits the therapeutic benefits. Thus, scientists have attempted anti-dsDNA antibodies or lupus-specific strategies, such as the immature dendritic cell vaccine and immunoadsorption. Recently, synthetic mimic peptides (hCDR1, pCONs, DWEYS, FISLE-412, and ALW) that directly block anti-dsDNA autoantibodies have attracted attention, which could ameliorate lupus, decrease the serological autoantibody titer, reduce the deposition of renal autoantibodies, and improve pathological performance. These potent small peptide molecules are well tolerated, non-toxic, and non-immunogenic, which have demonstrated a benign safety profile and are expected to be hopeful candidates for SLE management. In this review, we clarify the role of anti-dsDNA antibodies in SLE, mainly focus on the current strategies targeting anti-dsDNA antibodies, and discuss their potential clinical value.

Anticentromere antibody induced by immunization with centromere protein and Freund's complete adjuvant may interfere with mouse early-stage embryo

BACKGROUND

Anticentromere antibody (ACA) is a member of the antinuclear antibody spectrum (ANAs) which has been speculated to be associated with subfertility. Thus, the present study aimed to investigate the induction of ACA production and its potential interference with early-stage embryos.

METHODS

Recombinant centromere protein-A (CENP-A) or centromere protein-B (CENP-B) and complete Freund's adjuvant (CFA) were used to immunize mice. Serum ACA level was then evaluated by using an indirect immunofluorescence test. Immunofluorescence assay was performed to detect IgG in follicles in ovarian tissues and early-stage embryos.

RESULTS

Following treatment, serum positive ACA was observed in mice treated with CENP and CFA. Furthermore, IgG were detected in follicular fluid and early-stage embryos from mice treated with CENP and CFA.

CONCLUSIONS

This study preliminarily indicated that ACA induced by CENP and CFA may penetrate into the living embryos of early-stage in mice.

Harnessing SLE Autoantibodies for Intracellular Delivery of Biologic Therapeutics

Intracellular delivery of therapeutic antibodies is highly desirable but remains a challenge for biomedical research and the pharmaceutical industry. Approximately two-thirds of disease-associated targets are found inside the cell. Difficulty blocking these targets with available drugs creates a need for technology to deliver highly specific therapeutic antibodies intracellularly. Historically, antibodies have not been believed to traverse the cell membrane and neutralize intracellular targets. Emerging evidence has revealed that anti-DNA autoantibodies found in systemic lupus erythematosus (SLE) patients can penetrate inside the cell. Harnessing this technology has the potential to accelerate the development of drugs against intracellular targets. Here, we dissect the mechanisms of the intracellular localization of SLE antibodies and discuss how to apply these insights to engineer successful cell-penetrating antibody drugs.

A robust strategy for proteomic identification of biomarkers of invasive phenotype complexed with extracellular heat shock proteins

As an extension of their orchestration of intracellular pathways, secretion of extracellular heat shock proteins (HSPs) is an emerging paradigm of homeostasis imperative to multicellular organization. Extracellular HSP is axiomatic to the survival of cells during tumorigenesis; proportional representation of specific HSP family members is indicative of invasive potential and prognosis. Further significance has been added by the knowledge that all cancer-derived exosomes have surface-exposed HSPs that reflect the membrane topology of cells that secrete them. Extracellular HSPs are also characteristic of chronic inflammation and sepsis. Accordingly, interrogation of extracellular HSPs secreted from cell culture models may represent a facile means of identifying translational biomarker signatures for targeting in situ. In the current study, we evaluated a simple peptide-based multivalent HSP affinity approach using the Vn96 peptide for low speed pelleting of HSP complexes from bioreactor cultures of cell lines with varying invasive phenotype in xenotransplant models: U87 (glioblastoma multiforme; invasive); HELA (choriocarcinoma; minimally invasive); HEK293T (virally transformed immortalized; embryonic). Proteomic profiling by bottom-up mass spectrometry revealed a comprehensive range of candidate biomarkers including primary HSP ligands. HSP complexes were associated with additional chaperones of prognostic significance such as protein disulfide isomerases, as well as pleiotropic metabolic enzymes, established as proportionally reflective of invasive phenotype. Biomarkers of inflammatory and mechanotransductive phenotype were restricted to the most invasive cell model U87, including chitinase CHI3L1, lamin C, amyloid derivatives, and histone isoforms.

Monoclonal anti-dsDNA antibody 2C10 escorts DNA to intracellular DNA sensors in normal mononuclear cells and stimulates secretion of multiple cytokines implicated in lupus pathogenesis

There have been many studies on the mechanisms of internalization of DNA–anti‐DNA immune complexes by cells, including the one used for rheumatoid factor‐expressing mouse B cells. In parallel, studies on the role of intracellular DNA sensors in the pathogenesis of systemic lupus erythematosus (SLE) have been conducted, including the one using a mouse model lacking one of the sensors. These and other data have established a framework for understanding the pathogenic role of anti‐DNA antibodies, but studies on normal cells are limited. Here, we used the monoclonal anti‐dsDNA antibody 2C10, 2‐kbp dsDNA and healthy human peripheral blood mononuclear cells (PBMCs) to test whether and how 2C10 and/or DNA cause pathology in normal cells. We found that on culture with PBMCs, 2C10 preferentially entered monocytes and that DNA enhanced this internalization. In contrast, DNA alone was not significantly internalized by monocytes, but 2C10 facilitated its internalization. This was suppressed by cytochalasin D, but not by methyl‐β‐cyclodextrin, chloroquine or an Fc blocker, suggesting the involvement of macropinocytosis in this process. Internalization of 2C10 and DNA together resulted in production of interferon (IFN)‐α, IFN‐γ, tumor necrosis factor (TNF)‐α, monocyte chemoattractant protein‐1 (MCP‐1), interleukin (IL)‐1β, IL‐6, IL‐10 and IL‐33 by PBMCs. Cytokine production was suppressed by chloroquine and shikonin, but not by RU.521, suggesting dependence on activation of the Toll‐like receptor (TLR)‐9 and absent in melanoma 2 (AIM‐2) pathways. These results established a simple model to demonstrate that anti‐DNA antibodies can cause dysregulation of cytokine network mimicking systemic lupus erythematosus in culture of normal PBMCs, and emphasize again the importance of maintaining anti‐DNA antibodies at low levels by treatment.

Anti-double Stranded DNA Antibodies: Origin, Pathogenicity, and Targeted Therapies

Systemic lupus erythematosus (SLE) is characterized by high-titer serological autoantibodies, including antibodies that bind to double-stranded DNA (dsDNA). The origin, specificity, and pathogenicity of anti-dsDNA antibodies have been studied from a wider perspective. These autoantibodies have been suggested to contribute to multiple end-organ injuries, especially to lupus nephritis, in patients with SLE. Moreover, serum levels of anti-DNA antibodies fluctuate with disease activity in patients with SLE. By directly binding to self-antigens or indirectly forming immune complexes, anti-dsDNA antibodies can accumulate in the glomerular and tubular basement membrane. These autoantibodies can also trigger the complement cascade, penetrate into living cells, modulate gene expression, and even induce profibrotic phenotypes of renal cells. In addition, the expression of suppressor of cytokine signaling 1 is reduced by anti-DNA antibodies simultaneously with upregulation of profibrotic genes. Anti-dsDNA antibodies may even participate in the pathogenesis of SLE by catalyzing hydrolysis of certain DNA molecules or peptides in cells. Recently, anti-dsDNA antibodies have been explored in greater depth as a therapeutic target in the management of SLE. A substantial amount of data indicates that blockade of pathogenic anti-dsDNA antibodies can prevent or even reverse organ damage in murine models of SLE. This review focuses on the recent research advances regarding the origin, specificity, classification, and pathogenicity of anti-dsDNA antibodies and highlights the emerging therapies associated with them.

Anti-β2 -glycoprotein I antibody with DNA binding activity enters living monocytes via cell surface DNA and induces tissue factor expression

Autoantibodies characteristic for anti‐phospholipid syndrome (APS) and systemic lupus erythematosus (SLE) are anti‐β₂‐glycoprotein I (β₂GPI) antibodies and anti‐DNA antibodies, respectively, and almost half of APS cases occur in SLE. Anti‐β₂GPI antibodies are recognized to play a pivotal role in inducing a prothrombotic state, but the precise mechanism has not been fully elucidated. In a widely accepted view, binding of anti‐β₂GPI antibodies to cell surface β₂GPI in monocytes and endothelial cells triggers the Toll‐like receptor 4‐myeloid differentiation primary response 88 (TLR)‐4‐MyD88) signaling pathway which leads to activation of p38 mitogen‐activated protein kinase (MAPK), mitogen‐activated protein kinase kinase 1/extracellular signal‐regulated kinases (MEK‐1/ERK) and/or nuclear factor kappa B (NF‐κB) and expression of tissue factor (TF). However, resting cells do not express substantial amounts of TLR‐4. Previously, we generated a mouse monoclonal anti‐β₂GPI antibody WB‐6 and showed that it induced a prothrombotic state – including TF expression on circulating monocytes – in normal mice. In the current study, we aimed to clarify the mechanism of interaction between WB‐6 and resting monocytes, and found that WB‐6 exhibits binding activity to DNA and enters living monocytes or a monocytic cell line and, to a lesser extent, vascular endothelial cells. Treatment of the cells with DNase I reduced the internalization, suggesting the involvement of cell surface DNA in this phenomenon. Monocytes harboring internalized WB‐6 expressed TF and tumor necrosis factor (TNF)‐α which, in turn, stimulated endothelial cells to express intercellular adhesion molecule 1 (ICAM‐I) and vascular cell adhesion molecule 1 (VCAM‐I). These results suggest the possibility that a subset of anti‐β₂GPI antibodies with dual reactivity to DNA possesses ability to stimulate DNA sensors in the cytoplasm, in addition to the cell surface receptor‐mediated pathways, leading to produce proinflammatory and prothrombotic states.