The effects of vasoactive intestinal peptide in the rat model of experimental autoimmune neuritis and the implications for treatment of acute inflammatory demyelinating polyradiculoneuropathy or Guillain-Barré syndrome

Reduction in experimental autoimmune thyroiditis by IgG Fc fragments bearing regRF epitopes

Previously, we identified a new immunoregulatory factor, the production of which provides rats with resistance to certain experimental autoimmune diseases. It has been named regulatory rheumatoid factor (regRF). RegRF inhibits the expansion of CD4 T lymphocytes by killing activated cells. CD4 T cells are essential for antibody production against a majority of antigens and for the generation of cytotoxic T cells; therefore, regRF is an attractive therapeutic biotarget for T-cell and antibody-mediated autoimmune diseases. RegRF is anti-idiotypic antibodies that have a shared paratope in addition to an individual paratope. Epitopes specific to the shared regRF paratope (regRF epitopes) can be obtained on conformers of IgG Fc fragments. Immunization with Fc fragments carrying regRF epitopes reduces rat collagen-induced arthritis and diminishes experimental autoimmune encephalomyelitis. The aim of this study was to determine whether IgG Fc fragments bearing regRF epitopes suppress experimental autoimmune thyroiditis (EAT). Four weeks after EAT induction, rats were immunized with IgG Fc fragments exhibiting regRF epitopes. Histology studies of the thyroid were performed 4 weeks later. Thyroid function and other parameters were also evaluated. Treatment of rats with Fc fragments bearing regRF epitopes decreased the number of rats affected by EAT, significantly decreased the extent of thyroid damage, prevented thyroid metaplasia, and restored normal thyroid hormone production. Therefore, RegRF is a promising biotarget in autoimmune thyroiditis, and Fc fragments bearing regRF epitopes are a potential therapeutic agent for that condition.

New evidence for secondary axonal degeneration in demyelinating neuropathies

Development of peripheral nervous system (PNS) myelin involves a coordinated series of events between growing axons and the Schwann cell (SC) progenitors that will eventually ensheath them. Myelin sheaths have evolved out of necessity to maintain rapid impulse propagation while accounting for body space constraints. However, myelinating SCs perform additional critical functions that are required to preserve axonal integrity including mitigating energy consumption by establishing the nodal architecture, regulating axon caliber by organizing axonal cytoskeleton networks, providing trophic and potentially metabolic support, possibly supplying genetic translation materials and protecting axons from toxic insults. The intermediate steps between the loss of these functions and the initiation of axon degeneration are unknown but the importance of these processes provides insightful clues. Prevalent demyelinating diseases of the PNS include the inherited neuropathies Charcot-Marie-Tooth Disease, Type 1 (CMT1) and Hereditary Neuropathy with Liability to Pressure Palsies (HNPP) and the inflammatory diseases Acute Inflammatory Demyelinating Polyneuropathy (AIDP) and Chronic Inflammatory Demyelinating Polyneuropathy (CIDP). Secondary axon degeneration is a common feature of demyelinating neuropathies and this process is often correlated with clinical deficits and long-lasting disability in patients. There is abundant electrophysiological and histological evidence for secondary axon degeneration in patients and rodent models of PNS demyelinating diseases. Fully understanding the involvement of secondary axon degeneration in these diseases is essential for expanding our knowledge of disease pathogenesis and prognosis, which will be essential for developing novel therapeutic strategies.

Effects of microRNA-338 Transfection into Sciatic Nerve on Rats with Experimental Autoimmune Neuritis

Nerve demyelination or axonal lesions are characteristic of experimental autoimmune neuritis (EAN). Previous studies have demonstrated that microRNA-338 can regulate the differentiation and maturation of oligodendrocytes and Schwann cells and promote injured peripheral nerves in rats. In this study, we used microRNA-338 coded lentivirus vector (miR-338-LV) in a Lewis rat EAN model, in with the conjunction P0 peptide 180-199 which was injected into the footpads of animals to induce immunization. The clinical scores of miR-338-LV and intravenous immunoglobulin (IVIg) (positive drug) groups were significantly superior to those of untreated group at disease peak and disease plateau (p < 0.05). The nerve conduction velocity and the compound nerve action potential amplitude of miR-338-LV and IVIg groups increased significantly compared to those of the untreated group at disease peak (p < 0.01). At disease peak, myelin swelling, cavity formation, and lamellae separation showed improvement in miR-338-LV and IVIg groups compared to untreated group. S100 and NF200 expression in miR-338-LV and IVIg groups increased compared to that in untreated group. Iba1 and S100 co-expression in Schwann cells in miR-338-LV and IVIg groups decreased compared to that in untreated group, which was indicative of the reduced conversion of Schwann cells into inflammatory cells. Overall, miR-338-LV in sciatic nerves might improve neuromuscular function in EAN by inhibiting the conversion of Schwann cells into inflammatory cells.