Targeting remyelination treatment for multiple sclerosis

High-throughput screening for myelination promoting compounds using human stem cell-derived oligodendrocyte progenitor cells

Promoting myelination capacity of endogenous oligodendrocyte precursor cells (OPCs) is a promising therapeutic approach for CNS demyelinating disorders such as Multiple Sclerosis (MS). To aid in the discovery of myelination-promoting compounds, we generated a genome-engineered human pluripotent stem cell (hPSC) line that consists of three reporters: identification-and-purification tag, GFP, and secreted-NanoLuc, driven by the endogenous PDGFRA, PLP1, and MBP genes, respectively. Using this cell line, we established a high-throughput drug screening platform and performed a small-molecule screen, which identified at least two myelination-promoting small-molecule (Ro1138452 and SR2211) that target prostacyclin (IP) receptor and retinoic acid receptor-related orphan receptor γ (RORγ), respectively. Single-cell-transcriptomic analysis of differentiating OPCs treated with these molecules further confirmed that they promote oligodendrocyte differentiation and revealed several pathways that are potentially modulated by them. The molecules and their target pathways provide promising targets for the possible development of remyelination-based therapy for MS and other demyelinating disorders.

Diosgenin ameliorates cellular and molecular changes in multiple sclerosis in C57BL/6 mice

Multiple sclerosis (MS) is especially known as a demyelinating disease of the central nervous system. Current treatments for MS are mostly based on controlling neuroinflammation and there are no treatments to promote the remyelination process at present. Diosgenin is a known herbal anti-inflammatory and antioxidant agent, which has also been shown to stimulate the growth of myelin in vitro. However, there is no or little evidence about diosgenin effects; specially on myelination, neuroprotection and its corresponding mechanisms in vivo in experimental autoimmune encephalomyelitis (EAE) as the most valid experimental model of MS. In this study, the therapeutic effect of diosgenin on clinical signs of EAE, and the corresponding cellular and molecular mechanisms have been examined with emphasis on myelination and neuroprotection mechanisms. EAE was induced using myelin oligodendrocyte glycoprotein (MOG) antigen in C57BL/6 mice. Diosgenin was gavaged (100 mg/kg) daily with the onset of paralysis signs (half tail paralysis) until the 18th post-immunization day in the treatment group. Blood and spinal cord tissue sampling was performed on post-immunization day 18. Lumbar spinal cord inflammation, demyelination, and axonal degeneration were assessed using Hematoxylin and Eosin (H & E), Luxol Fast Blue (LFB), and Bielschowsky's silver staining methods, respectively. Serum and spinal cord tissue level of tumor necrosis factor alpha (TNFα) and tissue levels of matrix metalloproteinase 9 (MMP-9) and interleukin 17 (IL-17) as inflammatory markers, microtubule-associated proteins 1A/1B light chain 3A (MAP1LC3A), and activity dependent neuroprotector homeobox (ADNP) as neuroprotective markers were assayed using enzyme linked immunosorbent assay (ELISA) method. The clinical score of EAE in the diosgenin treatment group was significantly reduced compared to the EAE group on days 15 to 18 after induction of the EAE (p < 0.001). Inflammation, demyelination and axonal loss scores also decreased significantly in the diosgenin treatment group compared to the EAE group (p < 0.05). Serum and spinal cord tissue level of TNFα and tissue level of MMP-9 considerably decreased in the diosgenin treatment group in comparison with the EAE group (p < 0.01). Diosgenin treatment had no significant effects on the tissue levels of IL-17, ADNP and MAP1LC3A. Therefore, diosgenin improved the clinical signs of EAE through lowering neuroinflammation, demyelination and axonal degeneration, but did not significantly affect the neuroprotective factors in this study. As a result, diosgenin could be a good candidate for new MS treatment strategies that, in addition to their anti-inflammatory effects, also enhance myelination.

Association Between Exposure of Ipratropium and Salmeterol and Diagnosis of Multiple Sclerosis: A Matched Case-control Study

PURPOSE

Ipratropium and salmeterol were found to stimulate oligodendrocyte differentiation in a high-throughput drug screening assay; thus, they may play a role in the risk reduction of multiple sclerosis (MS). So far, they have not been examined in any clinical data. This study aims at investigating the association between ipratropium and salmeterol and reduced diagnosis of MS with the use of real-world clinical data.

METHODS

We conducted a 1:10 matched case-control study that compared the exposure of ipratropium and salmeterol between patients with MS and control patients over the past 2 years, using the MS Flowsheet Registry of OSF HealthCare Saint Francis Medical Center. Cases were matched to control patients, based on service year/quarter, age, sex, race, and payer type. The relationship was examined with a Poisson regression model and a generalized structural equation model.

FINDINGS

The sample in our analysis included 217 patients with MS and 2164 matched control patients. The mean (SD) age for both patients with MS and control patients was 41 (11.8) years with a range of 18 to 75 years. The MS group had consistently less prescriptions of ipratropium and salmeterol than the control group in the past 1, 2, and 3 years before the index date. Our multivariable analysis found that the control group had 3.2 more prescriptions (95% CI, 1.4-7.1; P = 0.006) of either ipratropium or salmeterol in the past 2 years than the MS group, even if controlling for other confounders. In the generalized structural equation model, we found that use of ipratropium and salmeterol was significantly associated with reduced diagnosis of MS (P = 0.036), whereas smokers and people with family history of MS were more likely to have a diagnosis of MS (P < 0.001).

IMPLICATIONS

The observed association between ipratropium and salmeterol use and reduced diagnosis of MS indicates that they might potentially serve as agents in the treatment of MS.

Repurposing HAMI3379 to Block GPR17 and Promote Rodent and Human Oligodendrocyte Differentiation

Identification of additional uses for existing drugs is a hot topic in drug discovery and a viable alternative to de novo drug development. HAMI3379 is known as an antagonist of the cysteinyl-leukotriene CysLT₂ receptor, and was initially developed to treat cardiovascular and inflammatory disorders. In our study we identified HAMI3379 as an antagonist of the orphan G protein-coupled receptor GPR17. HAMI3379 inhibits signaling of recombinant human, rat, and mouse GPR17 across various cellular backgrounds, and of endogenous GPR17 in primary rodent oligodendrocytes. GPR17 blockade by HAMI3379 enhanced maturation of primary rat and mouse oligodendrocytes, but was without effect in oligodendrocytes from GPR17 knockout mice. In human oligodendrocytes prepared from inducible pluripotent stem cells, GPR17 is expressed and its activation impaired oligodendrocyte differentiation. HAMI3379, conversely, efficiently favored human oligodendrocyte differentiation. We propose that HAMI3379 holds promise for pharmacological exploitation of orphan GPR17 to enhance regenerative strategies for the promotion of remyelination in patients.

Neuroprotective effects of ellagic acid on cuprizone-induced acute demyelination through limitation of microgliosis, adjustment of CXCL12/IL-17/IL-11 axis and restriction of mature oligodendrocytes apoptosis

CONTEXT

Ellagic acid (EA) is a natural phenol antioxidant with various therapeutic activities. However, the efficacy of EA has not been examined in neuropathologic conditions.

OBJECTIVE

In vivo neuroprotective effects of EA on cuprizone (cup)-induced demyelination were evaluated.

MATERIAL AND METHODS

C57BL/6 J mice were fed with chow containing 0.2% cup for 4 weeks to induce oligodendrocytes (OLGs) depletion predominantly in the corpus callosum (CC). EA was administered at different doses (40 or 80 mg/kg body weight/day/i.p.) from the first day of cup diet. Oligodendrocytes apoptosis [TUNEL assay and myelin oligodendrocyte glycoprotein (MOG⁺)/caspase-3⁺ cells), gliosis (H&E staining, glial fibrillary acidic protein (GFAP⁺) and macrophage-3 (Mac-3⁺) cells) and inflammatory markers (interleukin 17 (IL-17), interleukin 11 (IL-11) and stromal cell-derived factor 1 α (SDF-1α) or CXCL12] during cup intoxication were examined.

RESULTS

High dose of EA (EA-80) increased mature oligodendrocytes population (MOG⁺ cells, p < 0.001), and decreased apoptosis (p < 0.05) compared with the cup mice. Treatment with both EA doses did not show any considerable effects on the expression of CXCL12, but significantly down-regulated the expression of IL-17 and up-regulated the expression of IL-11 in mRNA levels compared with the cup mice. Only treatment with EA-80 significantly decreased the population of active macrophage (MAC-3⁺ cells, p < 0.001) but not reactive astrocytes (GFAP⁺ cells) compared with the cup mice.

DISCUSSION AND CONCLUSION

In this model, EA-80 effectively reduces lesions via reduction of neuroinflammation and toxic effects of cup on mature OLGs. EA is a suitable therapeutic agent for moderate brain damage in neurodegenerative diseases such as multiple sclerosis.