APOE ε3 attenuates experimental autoimmune neuritis by modulating T cell, macrophage and Schwann cell functions

The analysis of serum lipids profile in Guillain-Barre syndrome

Background

Guillain-Barre syndrome (GBS) is an immune-mediated inflammatory peripheral neuropathy. This study aimed to conduct a systematic analysis of the serum lipids profile in GBS.

Methods

We measured the serum lipids profile in 85 GBS patients and compared it with that of 85 healthy controls matched for age and sex. Additionally, we analyzed the correlation between lipids and the severity, subtypes, precursor infections, clinical outcomes, clinical symptoms, immunotherapy, and other laboratory markers of GBS.

Results

Compared to the healthy controls, GBS exhibited significantly elevated levels of Apolipoprotein B (APOB), Apolipoprotein C2 (APOC2), Apolipoprotein C3 (APOC3), Apolipoprotein E (APOE), triglycerides (TG), and residual cholesterol (RC). Conversely, Apolipoprotein A1 (APOA1), Apolipoprotein A2 (APOA2), and high-density lipoprotein (HDL) were substantially lower in GBS. Severe GBS displayed noticeably higher levels of APOC3 and total cholesterol (TC) compared to those with mild disease. Regarding different clinical outcomes, readmitted GBS demonstrated higher RC expression than those who were not readmitted. Moreover, GBS who tested positive for neuro-virus antibody IGG in cerebrospinal fluid (CSF) exhibited heightened expression of APOC3 in comparison to those who tested negative. GBS with cranial nerve damage showed significantly reduced expression of HDL and APOA1 than those without such damage. Additionally, GBS experiencing limb pain demonstrated markedly decreased HDL expression. Patients showed a significant reduction in TC after intravenous immunoglobulin therapy. We observed a significant positive correlation between lipids and inflammatory markers, including TNF-α, IL-1β, erythrocyte sedimentation rate (ESR), white blood cells, monocytes, and neutrophils in GBS. Notably, APOA1 exhibited a negative correlation with ESR. Furthermore, our findings suggest a potential association between lipids and the immune status of GBS.

Conclusion

The research demonstrated a strong connection between lipids and the severity, subtypes, clinical outcomes, precursor infections, clinical symptoms, immunotherapy, inflammation, and immune status of GBS. This implies that a low-fat diet or the use of lipid-lowering medications may potentially serve as an approach for managing GBS, offering a fresh viewpoint for clinical treatment of this condition.

Bowman-Birk inhibitor concentrate suppresses experimental autoimmune neuritis via shifting macrophages from M1 to M2 subtype

BACKGROUND

In the present study, we investigated the immuno-regulatory and therapeutic effects of Bowman-Birk inhibitor concentrate (BBIC) on experimental autoimmune neuritis (EAN), an animal model of Guillain-Barré syndrome (GBS) in human.

METHODS

EAN in Lewis rats induced by inoculation with peripheral nerve myelin P0 protein peptide 180-199 (P0 peptide) was treated with BBIC at two different therapeutic regimens.

RESULTS

Our data indicated that the administration of BBIC daily orally effectively inhibited and ameliorated the clinical and pathological signs of EAN. The suppression of EAN was associated with an insufficiency of autoreactive T cells, as reflected by inhibited P0 peptide-specific mononuclear cell proliferation and decreased in CD4 and CD8T cells infiltrating into the peripheral nervous system (PNS). BBIC might mediate its therapeutic effects by shifting macrophages from M1 to M2 subtype as evidenced by increasing Arg-1, CD206 and IL-10 and inhibiting IFN-γ, TNF-α, IL-12, iNOS and CD40 expressions on macrophages as well as enhancing anti-inflammatory cytokines IL-4 and IL-10 and decreasing inflammatory cytokines, IFN-γ, TNF-α and IL-17 in the PNS.

CONCLUSION

Our results suggest that BBIC may have therapeutic potential in human GBS and other autoimmune diseases in the future.

New strategies in the management of Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is an acute and usually monophasic, neurological, demyelinating disease. Although most patients have good outcomes without sequelae after conventional plasma exchange and intravenous immunoglobulin therapy, 20% of patients continue to have severe disease and 5% die of their disease. Therefore, there is an obvious need for more acceptable and efficacious therapies. Experimental autoimmune neuritis (EAN) is the classical animal model for GBS. As there is no specific drug for GBS, several drugs targeting the humoral and cellular components of the immune response have been used to treat EAN in the endeavour to find new treatment alternatives for GBS. This review focused on some new strategies for GBS, which have been reported but have not yet been widely used, and on the main drugs which have been investigated in EAN.

Attenuated EAN in TNF-α deficient mice is associated with an altered balance of M1/M2 macrophages

The role of tumor necrosis factor (TNF)-α and its receptors in neuroautoimmune and neuroinflammatory diseases has been controversial. On the basis of our previous studies, we hereby aimed to further clarify TNF-α's mechanism of action and to explore the potential role of TNF-α receptor (TNFR)1 as a therapeutic target in experimental autoimmune neuritis (EAN). EAN was induced by immunization with P0 peptide 180-199 in TNF-α knockout (KO) mice and anti-TNFR1 antibodies were used to treat EAN. Particularly, the effects of TNF-α deficiency and TNFR1 blockade on macrophage functions were investigated. The onset of EAN in TNF-α KO mice was markedly later than that in wild type (WT) mice. From day 14 post immunization, the clinical signs of TNF-α KO mice were significantly milder than those of their WT counterparts. Further, we showed that the clinical severity of WT mice treated with anti-TNFR1 antibodies was less severe than that of the control WT mice receiving PBS. Nevertheless, no difference with regard to the clinical signs of EAN or inflammatory infiltration in cauda equina was seen between TNF-α KO and WT mice with EAN after blockade of TNFR1. Although TNF-α deficiency did not alter the proliferation of lymphocytes in response to either antigenic or mitogenic stimuli, it down-regulated the production of interleukin (IL)-12 and nitric oxide (NO), and enhanced the production of IL-10 in macrophages. Increased ratio of regulatory T cells (Tregs) and reduced production of interferon (IFN)-γ in cauda equina infiltrating cells, and elevated levels of IgG2b antibodies against P0 peptide 180-199 in sera were found in TNF-α KO mice with EAN. In conclusion, TNF-α deficiency attenuates EAN via altering the M1/M2 balance of macrophages.

Apolipoprotein E4 domain interaction accelerates diet-induced atherosclerosis in hypomorphic Arg-61 apoe mice

OBJECTIVE

Apolipoprotein (apo) E4 is an established risk factor for atherosclerosis, but the structural components underlying this association remain unclear. ApoE4 is characterized by 2 biophysical properties: domain interaction and molten globule state. Substituting Arg-61 for Thr-61 in mouse apoE introduces domain interaction without molten globule state, allowing us to delineate potential proatherogenic effects of domain interaction in vivo.

METHODS AND RESULTS

We studied atherosclerosis susceptibility of hypomorphic Apoe mice expressing either Thr-61 or Arg-61 apoE (ApoeT(h/h) or ApoeR(h/h)mice). On a chow diet, both mouse models were normolipidemic with similar levels of plasma apoE and lipoproteins. However, on a high-cholesterol diet, ApoeR(h/h) mice displayed increased levels of total plasma cholesterol and very-low-density lipoprotein as well as larger atherosclerotic plaques in the aortic root, arch, and descending aorta compared with ApoeT(h/h) mice. In addition, evidence of cellular dysfunction was identified in peritoneal ApoeR(h/h) macrophages which released lower amounts of apoE in culture medium and displayed increased expression of major histocompatibility complex class II molecules.

CONCLUSIONS

These data indicate that domain interaction mediates proatherogenic effects of apoE4 in part by modulating lipoprotein metabolism and macrophage biology. Pharmaceutical targeting of domain interaction could lead to new treatments for atherosclerosis in apoE4 individuals.

Apolipoprotein E isoform-specific effects on cytokine and nitric oxide production from mouse Schwann cells after inflammatory stimulation

Previously, we reported that apolipoprotein E (apoE) deficiency increased the susceptibility to experimental autoimmune neuritis (EAN), an inflammatory autoimmune disorder of the peripheral nervous system (PNS) and an animal model for human Guillain-Barré syndrome (GBS) by affecting the antigen-presenting function of Schwann cells (SCs) via influence upon IL-6 production. To further elucidate the role of apoE in inflammation of the PNS, here we studied the effect of different isoforms of apoE on SCs in response to inflammatory stimulation. SCs from apoE2, E3 and E4 transgenic (Tg) and wild type (WT) mice were cultured, and their responses to stimulation by lipopolysaccharide (LPS) plus interferon (IFN)-γ were compared. Upon stimulation, the morphology of cultured SCs changed. Pronounced production of interleukin (IL)-6 and IL-10 within SCs, and of IL-6 and nitric oxide (NO) in the supernatants were found in an isoform-dependent manner (apoE3>apoE2≈apoE4). Further results indicated that both nuclear factor (NF) κB and Akt signaling pathways were involved in the process by the same isoform-dependent pattern. However, the expression of co-stimulatory molecules as showing the antigen-presenting capacity of SCs was not significantly different among these groups. In conclusion, SCs respond to inflammatory insults accompanied by increased productions of IL-6, IL-10 and NO in an apoE-isoform-dependent manner. SCs from apoE2 and apoE4 Tg mice seem to bear some dysfunction in producing cytokines (IL-6 and IL-10) and NO as compared with their apoE3 counterparts, probably resulting from their insufficiency to suppress the activation of NFκB and Akt pathways. Our findings may help to understand the role of different isoforms of apoE in inflammatory disorders of the PNS.