Spatial and motor abilities during the course of autoimmune disease in (NZW×BXSB)F1 lupus-prone mice

Animal models of neuropsychiatric systemic lupus erythematosus: deciphering the complexity and guiding therapeutic development

Systemic lupus erythematosus (SLE) poses formidable challenges due to its multifaceted etiology while impacting multiple tissues and organs and displaying diverse clinical manifestations. Genetic and environmental factors contribute to SLE complexity, with relatively limited approved therapeutic options. Murine models offer insights into SLE pathogenesis but do not always replicate the nuances of human disease. This review critically evaluates spontaneous and induced animal models, emphasizing their validity and relevance to neuropsychiatric SLE (NPSLE). While these models undoubtedly contribute to understanding disease pathophysiology, discrepancies persist in mimicking some NPSLE intricacies. The lack of literature addressing this issue impedes therapeutic progress. We underscore the urgent need for refining models that truly reflect NPSLE complexities to enhance translational fidelity. We encourage a comprehensive, creative translational approach for targeted SLE interventions, balancing scientific progress with ethical considerations to eventually improve the management of NPSLE patients. A thorough grasp of these issues informs researchers in designing experiments, interpreting results, and exploring alternatives to advance NPSLE research.

(NZW × BXSB) F1 male mice: An unusual, severe and fatal mouse model of lupus erythematosus

Background

Systemic lupus erythematosus (SLE) is a chronic autoimmune/inflammatory disease. The heterogeneity and complexity of clinical presentation has made it challenging to study or treat this syndrome. The (NZW×BXSB) F1 lupus-prone male mouse model of this disease is potentially useful to study mechanism and treatment modalities, but there is a lack of information about this model’s characterization and disease progression. Therefore, the aim was to examine this lupus model’s physical/clinical disease presentation and its immunological status.

Materials and methods

Clinical and physical status were observed in 8- and 16-week-old male and female (± 1 week) (NZW/LacJ x BXSB/MpJ) F1 mice (n = 8 per group). Young males (8 ± 1 week) without disease and female (16 ± 1 week) mice served as controls. Physical changes, quantitative values of autoantibodies, and blood cell parameters were determined. Necropsy and post-mortem histopathology were also performed.

Results

With aging (≥ 12 weeks), significant increases in severe abdominal distension/swelling, inability to walk, paleness of paws and significant weight increase were observed compared to controls (p < 0.05). The necropsy examination showed abdominal distension associated with serous effusion and histological examination identified severe edema and multi-organ abnormalities (spleen, lymph nodes, and kidney). Significant increases in anti-double-stranded DNA antibody (anti-dsDNA) was seen in old/sick compared to female (p = 0.0002) or young male (p = 0.0036) mice. Old mice developed immune thrombocytopenia compared to female (p = 0.0056) and young male (p = 0.0007) mice. Anti-platelet was detectable in old, sick mice. The mortality rate increased with aging; more than 35% of male mice died during this study between the ages of 13-18 weeks.

Conclusion

We found that the (NZW/LacJ x BXSB/MpJ) F1 male mice spontaneously exhibit, over varying lengths of time, extremely severe and fatal clinical disease symptoms. This model may be too severe to be helpful in investigating SLE and testing potential treatment modalities.

Diagnosis and early detection of CNS-SLE in MRL/lpr mice using peptide microarrays

Background

An accurate method that can diagnose and predict lupus and its neuropsychiatric manifestations is essential since currently there are no reliable methods. Autoantibodies to a varied panel of antigens in the body are characteristic of lupus. In this study we investigated whether serum autoantibody binding patterns on random-sequence peptide microarrays (immunosignaturing) can be used for diagnosing and predicting the onset of lupus and its central nervous system (CNS) manifestations. We also tested the techniques for identifying potentially pathogenic autoantibodies in CNS-Lupus. We used the well-characterized MRL/lpr lupus animal model in two studies as a first step to develop and evaluate future studies in humans.

Results

In study one we identified possible diagnostic peptides for both lupus and altered behavior in the forced swim test. When comparing the results of study one to that of study two (carried out in a similar manner), we further identified potential peptides that may be diagnostic and predictive of both lupus and altered behavior in the forced swim test. We also characterized five potentially pathogenic brain-reactive autoantibodies, as well as suggested possible brain targets.

Conclusions

These results indicate that immunosignaturing could predict and diagnose lupus and its CNS manifestations. It can also be used to characterize pathogenic autoantibodies, which may help to better understand the underlying mechanisms of CNS-Lupus.

Anti-alpha-internexin autoantibody from neuropsychiatric lupus induce cognitive damage via inhibiting axonal elongation and promote neuron apoptosis

BACKGROUND

Neuropsychiatric systemic lupus erythematosus (NPSLE) is a major complication for lupus patients, which often leads to cognitive disturbances and memory loss and contributes to a significant patient morbidity and mortality. The presence of anti-neuronal autoantibodies (aAbs) has been identified; as examples, anti-NMDA receptors and anti-Ribsomal P aAbs have been linked to certain pathophysiological features of NPSLE.

METHODS AND FINDINGS

In the current study, we used a proteomic approach to identify an intermediate neurofilament alpha-internexin (INA) as a pathogenetically relevant autoantigen in NPSLE. The significance of this finding was then validated in an expanded of a cohort of NPSLE patients (n = 67) and controls (n = 270) by demonstrating that high titers of anti-INA aAb was found in both the serum and cerebrospinal fluid (CSF) of approximately 50% NPSLE. Subsequently, a murine model was developed by INA immunization that resulted in pronounced cognitive dysfunction that mimicked features of NPSLE. Histopathology in affected animals displayed cortical and hippocampal neuron apoptosis. In vitro studies further demonstrated that anti-INA Ab mediated neuronal damage via inhibiting axonal elongation and eventually driving the cells to apoptosis.

CONCLUSIONS

Taken together, this study identified a novel anti-neurofilament aAb in NPSLE, and established a hitherto undescribed mechanism of aAb-mediated neuron damage that could have relevance to the pathophysiology of NPSLE.

Amelioration of brain pathology and behavioral dysfunction in mice with lupus following treatment with a tolerogenic peptide

OBJECTIVE

Central nervous system (CNS) involvement in systemic lupus erythematosus (SLE) is manifested by neurologic deficits and psychiatric disorders. The aim of this study was to examine SLE-associated CNS pathology in lupus-prone (NZBxNZW)F1 (NZB/NZW) mice, and to evaluate the ameliorating effects of treatment with a tolerogenic peptide, hCDR1 (human first complementarity-determining region), on these manifestations.

METHODS

Histopathologic analyses of brains from lupus-prone NZB/NZW mice treated with vehicle, hCDR1, or a control scrambled peptide were performed. The messenger RNA expression of SLE-associated cytokines and apoptosis-related molecules from the hippocampi was determined. Anxiety-like behavior was assessed by open-field tests and dark/light transfer tests, and memory deficit was assessed using a novel object recognition test.

RESULTS

Infiltration was evident in the hippocampi of the lupus-afflicted mice, and the presence of CD3+ T cells as well as IgG and complement C3 complex deposition was observed. Furthermore, elevated levels of gliosis and loss of neuronal nuclei immunoreactivity were also observed in the hippocampi of the mice with lupus. Treatment with hCDR1 ameliorated the histopathologic changes. Treatment with hCDR1 down-regulated the high expression of interleukin-1beta (IL-1beta), IL-6, IL-10, interferon-gamma, transforming growth factor beta, and the proapoptotic molecule caspase 8 in the hippocampi of the mice with lupus, and up-regulated expression of the antiapoptotic bcl-xL gene. Diseased mice exhibited increased anxiety-like behavior and memory deficit. Treatment with hCDR1 improved these parameters, as assessed by behavior tests.

CONCLUSION

Treatment with hCDR1 ameliorated CNS pathology and improved the tested cognitive and mood-related behavior of the mice with lupus. Thus, hCDR1 is a novel candidate for the treatment of CNS lupus.

Systemic lupus erythematosus and the brain: what mice are telling us

Neuropsychiatric symptoms occur in systemic lupus erythematosus (SLE), a complex, autoimmune disease of unknown origin. Although several pathogenic mechanisms have been suggested to play a significant role in the etiology of the disease, the exact underlying mechanisms still remain elusive. Several inbred strains of mice are used as models to study SLE, which exhibit a diversity of central nervous system (CNS) manifestations similar to that observed in patients. This review will attempt to give a brief overview of the CNS alterations observed in these models, including biochemical, structural and behavioral changes.