Newswise — MADISON, Wisconsin, March 9, 2017 – The Americas Committee for Treatment and Research in Multiple Sclerosis (ACTRIMS) recognized the research contributions of three young investigators during the recent ACTRIMS Forum 2017.

Nanocrystalline Gold As a Novel Remyelination Therapeutic for Multiple Sclerosis

Dr. Michael Hotchkin1, Dr. Joanne Zhang, PhD2, Prof. Andrew Robinson, PhD3, Dr. Haley Titus, PhD4, Ms. Molly Karl5, Dr. Karen S Ho, PhD1,6, Dr. Glen Frick, PhD, MD1, Prof. Stephen D Miller3, Prof. Robert Miller, PhD5 and Mr. Mark Mortenson7, (1)Clene Nanomedicine, Inc., Salt Lake City, UT, (2)Clene Nanomedicine, Inc., Northeast, MD, (3)Northwestern University, Chicago, IL, (4)Northwestern University, 303 E. Chicago Avenue, IL, (5)George Washington University, Washington, DC, (6)University of Utah, Salt Lake City, UT, (7)Clene Nanomedicine, Inc., North East, MD

Background: Pharmacotherapeutic strategies for Multiple Sclerosis (MS) have traditionally addressed the activated immune response against myelin. Although such agents may delay disease progression, they cannot restore function because they do not trigger the production of new myelin by oligodendrocytes (OL). Oligodendrocyte precursor cells (OPC) are present in adult brains and have been detected in and around MS lesions. However, activating their differentiation into mature myelin-producing oligodendrocytes has been challenging.We have developed a novel preparation of faceted, crystalline gold (Au) nanoparticles (~10 nm) that does not require stabilizing or capping processes related to colloidal preparations. This results in a suspension of faceted, clean-surfaced nanocrystals for development as an oral therapeutic.

Objectives: We aimed to show the efficacy of nanocrystalline Au (CNM-Au8) for remyelination.Methods: In vivo and in vitro myelination assays.

Results: Using in vivo cuprizone and lysolecithin models, we demonstrate using transmission electron microscopy (EM) and immunohistochemistry (IHC) of myelin markers (myelin basic protein (MBP), luxol fast blue (LFB)), robust remyelination response by CNM-Au8. CNM-Au8 demonstrated in vitro dose-dependent differentiation of enriched primary OPCs and was comparable to the activity of triiodothyronine (T3), (% MBP+ by IHC; 100% increase vs. vehicle, p<0.05). Efficacy was demonstrated by CNM-Au8 in both prophylactic as well as post-injury contexts in the cuprizone model, suggesting that CNM-Au8 may be useful in clinical settings after disease progression has occurred. Furthermore, open field behavioral and fine motor kinematic assays of cuprizone treated mice demonstrated that CNM-Au8 restored behavioral function following demyelination (Example: Central Vertical Rearing, least-squares mean difference (SE), 43.9 (20.5); p<0.05). In the lysolecithin model, CNM-Au8 resulted in increased myelin assessed by LFB staining, enhanced CC-1 positive OLs within the lesion, and improved myelin wrapping by quantitation of ultra-structural lesion microscopy (+43% myelin wrapped axons per unit area vs. vehicle, p<0.05).

Conclusion: CNM-Au8 consistently demonstrates remyelinating activity in in vitro, in vivo, and in functional behavioral assays in rodents. Faceted clean surfaced nanocrystalline gold is therefore a promising new therapeutic candidate for multiple sclerosis. Phase 2 human MS studies with CNM-Au8 will commence in 2018.

 

Oligodendrocyte Progenitor Cells Are Co-Opted By the Immune System to Cross-Present Antigen and Mediate Cytoxicity

Ms. Leslie A Kirby, BS1, Mrs. Jing Jin, MD, PhD1, Mr. Jaime Gonzalez-Cardona, MD2, Mrs. Jingya Wang, Ph.D.3, Mr. Kyle Martin2, Ms. Leyla Herbst2, Ms. Maya Alexis2, Mr. Todd Davidson, PhD3, Mrs. Jodi Karnell, Ph.D.3, Mr. Matthew Smith, BS4 and Dr. Peter A Calabresi, MD4, (1)Johns Hoplkins School of Medicine, Baltimore, MD, (2)Johns Hopkins School of Medicine, Baltimore, MD, (3)MedImmune, Gaithersburg, MD, (4)Johns Hopkins University, Baltimore, MD

Background: Oligodendrocyte progenitor cells (OPCs) have been a specific cell of interest in MS targeted therapies based on their ability to differentiate and replace mature oligodendrocytes in the process of remyelination. Several proinflammatory signaling molecules have been identified to inhibit OPC differentiation. However, limited investigation has been done into other signaling pathways that the OPCs might implement in response to their presence in the inflammatory microenvironment. We hypothesize that OPCs respond to proinflammatory cues and adopt an immunomodulatory phenotype in addition to suppression of their differentiation program.

Objectives: To determine the functional consequences of IFNg signaling mediated antigen presentation in OPCs.

Methods: OPCs isolated from neonate rodents were cultured under differentiating conditions with Thyroid hormone (T3) alone or T3 with additional supplementation of IFNg or IL-17. Microarray and gene enrichment analysis was completed. In vitro and in vivo functional assays were performed using OPC-CD8 co-culture systems and both EAE and cuprizone models. Flow cytometry and immunostaining were performed to confirm OPC antigen presentation of Ovalbumin protein or myelin peptide in co-culture or animal models, respectively.

Results: Gene array analysis of IFNg signaling in OPCs revealed the enrichment of cross-presentation and MHC class I antigen presentation signaling pathways. We determined by flow cytometry and immunostaining that OPCs can quickly and stably present foreign peptide on MHC class I molecules by both TAP1 dependent and independent means. OPC processing and presentation of Ovalbumin protein promoted OT-1 CD8 T-cell survival, proliferation, cytokine production and granular protein production resulting in cytotoxicity of the OPC targets. EAE mice were found to contain a population of OPCs that were positive for MHC class I molecules loaded with specific MBP79-87 peptide. OPCs from EAE mice exhibited up-regulation of FAS cell death receptor expression and significant increases in Caspase 3/7 activation. Future experimentation will involve FAS receptor neutralization and myelin specific CD8 T-cell transgenic mouse line utilization to confirm CD8 T-cell mediated OPC death in vivo.

Conclusion: We show a novel and important role for OPCs in the context of remyelination and CNS inflammation. In response to IFNg signaling, OPCs present antigen and activate cytotoxic T-cells, which ultimately promote OPC apoptosis and remyelination suppression.

 

Genetic Risk Variant for Multiple Sclerosis Drives Astrocyte Responses Associated with Lesion Formation

Dr. Gerald Ponath, PhD1, Dr. Matthew R Lincoln, MD DPhil1, Ms. Mayyan Mubarak2, Mrs. Somiah Dahlawi2, Dr. Tomokazu Sumida, MD PhD1, Dr. Laura Airas, MD, PhD2, Dr. Shun Zhang3, Dr. Thanh D. Nguyen3, Dr. David Hafler2 and Dr. David Pitt, MD2, (1)Yale University, New Haven, CT, (2)Yale School of Medicine, New Haven, CT, (3)Weill Cornell Medical College, NewYork, NY

Background: Epigenetic annotation studies of multiple sclerosis (MS) genetic risk variants implicate dysfunctional lymphocyte responses as major factor for MS susceptibility. It is unclear whether MS risk variants also impact on the cellular function in the target organ, i.e. the central nervous system (CNS).

Objectives: To determine the impact of the risk variant, rs7665090-G, located near the NFKB1 gene, on astrocyte function.

Methods: We determined chromatin accessibility at the risk locus in human fetal astrocytes, using an assay for transposase-accessible chromatin sequencing (ATAC-seq). We generated induced pluripotent stem cell-derived astrocytes obtained from MS patients, homozygous for the rs7665090 risk and protective variants, with which we performed cell-based assays. We subsequently genotyped MS autopsy tissue and performed immunohistochemistry to quantify protein expression in astrocytes and lymphocytic infiltrates within lesions. Finally, in MS patients with the risk and protective variants, we quantified lesion load on MRI.

Results: ATAC-seq in human fetal astrocytes suggests that chromatin is accessible in the haplotype block tagged by rs7665090. In stimulated iPSC-derived astrocytes, the risk variant was associated with enhanced NF-κB signaling and increased expression of specific NF-κB target genes that promote lymphocyte recruitment and neurotoxicity. Increased expression of NF-κB and NF-κB targets was also observed in situ in reactive astrocytes within MS lesions with the risk variant, which also contained more infiltrating lymphocytes. Moreover, MS patients homozygous for the risk variant exhibited an increased FLAIR lesion load compared to patients with the protective variant.

Conclusion: The rs7665090 risk variant is associated with functional changes in astrocytes that drive lymphocyte recruitment and thus lower the threshold for lesion formation, as suggested by the increased lesion load in MS patients. This provides evidence for the first time that MS risk variants directly perturb CNS cell functions. Thus, MS may be triggered by a complex interplay between the peripheral immune system and the CNS, where excessive immune responses are targeted to the CNS through dysfunctional astrocytes.

 

Natalizumab Extended Interval Dosing Is Associated with a Reduction in Progressive Multifocal Leukoencephalopathy (PML) Risk in the Touch® Registry

Dr. Lana Zhovtis Ryerson1, Dr. John Foley2, Dr. Ih Chang3, Dr. Ilya Kister4, Prof. Gary R Cutter5, Dr. Ryan Metzger2, Dr. Judith D Goldberg6, Dr. Xiaochun Li1, Dr. Evan Riddle7, Dr. Bei Yu3, Dr. Zheng Ren3, Dr. Christophe Hotermans3, Dr. Pei-Ran Ho3 and Dr. Nolan Campbell3, (1)NYU Langone Health, New York University, New York, NY, (2)Rocky Mountain MS Clinic, Salt Lake City, UT, (3)Biogen, Cambridge, MA, (4)NYU, New York, NY, (5)UAB School of Public Health, Birmingham, AL, (6)New York University School of Medicine, New York, NY, (7)Biogen, Farmington, UT

Background: Natalizumab, approved for 300 mg IV every 4 weeks dosing, has a known risk of PML. Extended interval dosing (EID) is sometimes practiced, especially in patients at high risk of PML, with the aim of reducing PML risk while maintaining efficacy. Prior studies have been inconclusive on EID’s impact on PML risk. The mandatory US REMS program (TOUCH) offers the largest data source that could inform on PML risk in patients on EID (90,038 patients as of June 1, 2017).

Objectives: To determine whether EID is associated with reduced PML risk.

Methods: Standard dosing (SD) and EID definition development and statistical analysis plan finalization occurred while blinded to PML events. Primary, secondary, and tertiary analyses assessed various SD and EID definitions. SD was based on average dosing intervals (ADI) of ≥3 to 5 to ≤12 weeks. The primary analysis assessed ADI in the last 18 months of recorded infusion history; the secondary identified any consecutive 6-month period of EID dosing in the infusion history; the tertiary assessed ADI over the full infusion history. Only anti-JC virus antibody positive (JCV Ab+) patients were included. Patients with a dosing interval >12 weeks or

Results: Analyses included 13,132 patients on SD and 1988 on EID for primary analyses, 15,424 SD and 3331 EID for secondary, and 23,168 SD and 815 EID for tertiary. Baseline demographics were well balanced across dosing groups. In primary analyses, ADI (days) was 29 for SD and 36 for EID; median exposure (months) was 44 for SD and 59 for EID. Most EID patients had >2 years of SD treatment prior to EID. PML hazard ratio (95% confidence intervals) was 0.06 (0.01‒0.22; P<0.001) for primary analyses, 0.12 (0.05‒0.29; P<0.001) for secondary analyses; no PML cases were observed with EID in tertiary analyses (KM log-rank test P=0.02).

Conclusion: These results suggest that in JCV Ab+ patients, natalizumab EID is associated with clinically and statistically significant reduction in PML risk as compared with SD. Effectiveness data is not collected in TOUCH, so benefit-risk of EID cannot be assessed. Limitations include potential bias as most EID patients received SD treatment first and did not get PML on SD prior to EID.

 

ACTRIMS Forum 2019 will be held February 28-March 2 in Dallas, Texas.

 

###

 

About ACTRIMS

Founded in 1995, Americas Committee for Treatment and Research in Multiple Sclerosis (ACTRIMS) is a community of leaders from the United States and Canada who are dedicated to the treatment and research in MS and other demyelinating diseases. ACTRIMS focuses on knowledge dissemination, education and collaboration among disciplines. ACTRIMS also provides a forum for experienced and newer clinicians and researchers to exchange information, debate current issues and discuss advances related to basic research and clinical issues.

 

Contact:

Kristin McGuine

kmcguine@actrims.org

MEDIA CONTACT
Register for reporter access to contact details