Research Summary

Dr. Lisak's research programs are in neuroimmunologic diseases including multiple sclerosis (MS) and related diseases including neuromyelitis optic spectrum disorders (NMOSD) and transverse myelitis (TM), myasthenia gravis (MG), immune-mediated neuropathies including Guillain-Barre Syndrome (GBS), Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) and variants as well as other autoimmune neuropathies and inflammatory diseases of muscle. His approach, dating back to the 1960s, has always been translational. These studies have encompassed basic (wet bench) and translational science and clinical research. The latter include characterization of clinical disorders, clinical trials including many multicenter trials that have lead to approval of several treatments for MS, MG and GBS.

Multiple Sclerosis and Related Disorders

MS is the most common potentially disabling non-traumatic disease of the central nervous system (CNS) of young adults and affects over 400,000 individuals and their families in the USA. Clinical signs and symptoms are variable but commonly include weakness, difficulty walking, imbalance, decreased sensation and tingling, various types of pain, difficulty with vision, double vision, problems with bladder and bowel control, sexual dysfunction, fatigue, and problems with mental functions and mood. The course is variable in individual patients and often not predictable.  Eighty five percent of patients present with relapses, relatively acute episodes of neurologic dysfunction followed by improvement, sometimes back to base line early in the disease. This is called relapsing remitting (RRMS) or relapsing MS (RMS). In the era prior to effective disease modifying therapies (DMTs) 50-85% of patient eventually transitioned in to a progressive course, often without superimposed relapses called secondary progressive MS (SPMS) Fifteen percent present with a progressive course without any obvious acute or subacute relapse-like episodes, called primary progressive MS (PPMS).

In our MS wet bench and translational research, done in collaboration with Dr Joyce Benjamins, Professor Emerita of Neurology at Wayne State University and others, we look at fundamental interactions of the immune system and the central nervous system in order to better plan new therapies for MS. Our current MS laboratory work examines the effect of cytokines and other mediators of inflammation on cells of the nervous system including oligodendrocytes (OL) and their precursors (OPC), astrocytes, microglia (the endogenous inflammatory cells of the central nervous system), and neurons. Studies have been focused on the protective and potential reparative effects of therapies already approved for other uses in MS and other diseases. These studies could point the way not only for use of these treatments for protective and reparative effects like enhancing remyelination, but by looking at the mechanisms of protection and repair by these agents, including adrenocortical trophic hormone (ACTH) and dextromethorphan (DM), newer treatments, like a series of sigma-1 receptor agonists, could also be developed that target the receptors for these molecules. We have also examined the effects of muscarinic receptors on glial cells. In our other studies, done in collaboration with Dr Amit Bar-Or, formerly of McGill University in Montreal and currently at the University of Pennsylvania, we have discovered a somewhat unexpected potential role for B lymphocytes (B-cells) in the pathogenesis of MS, particularly for the cortical gray matter. Gray matter lesions correlate with the degree of permanent disability and begin in the earliest stages of MS. It has always been felt that B cells which mature to become plasma blasts and plasma cells, the antibody producing cells of the body, were involved in MS by producing antibodies (autoantibodies) that attack the CNS particularly myelin and the OL, the cells that produce myelin in the CNS. But newer roles for B cells in the immune system have been discovered and our work suggests that B cells can produce substances, not immunoglobulins (Ig) that are directly toxic to OL and neurons. Such B cells resident in the meninges (the covering of the brain and spinal cord) could release these toxic factors and damage the OL/myelin and the neurons and axons in the underlying cortical gray matter. We demonstrated that toxic factor or factors released by the B cells which could then lead to a more specific therapy rather than simply destroying B cells in patients which is how the newer B cell MS therapies work.

Our studies have demonstrated the toxic effect is mediated by exosomes release by B cells. The current major thrust of the laboratory is using proteomics, lipidomics and mRNA Seq to characterize exosomes from B cells from MS patients and compare with controls.. Selective blocking of toxic factors in exosomes would not only be more specific and potentially more effective treatment but also safer.

Our clinical research related to MS and related disorders like Neuromyelitis Optica Spectrum Disorder (NMOSD) includes participation in many multicenter clinical trials as well as projects limited to our own patients. Until 1993 there were no known treatments that favorably altered the course of MS and basic studies on our laboratories and that of others have lead to the current status of at least 20 FDA approved treatments with more in the 'pipeline'. While none of the available agents are cures the change in the outlook for many patients with MS has been remarkable.

Selected Laboratory Studies Related to MS

1. Lisak, RP, Benjamins, JA, Bealmear, B, Nedelkoska, L, Studzinski, D, Retland, E, Yao, B, Land, S. Differential effects of Th1, monocyte/macrophage and Th2 cytokine mixtures on early gene expression for molecules associated with metabolism, signaling and regulation in central nervous system mixed glial cell cultures. J Neuroinflammation 6:4, 2009

2. Ragheb, S, Li, Y, Simon, K, Van Haerents, S, Galimberti, D, de Riz, M, Genoglio, C, Scarpini, E, Lisak, R. Multiplesclerosis: BAFF and CXCL 13 in cerebrospinal fluid. Mult Scler 17:819-829, 2011

3. Lisak, RP, Nedelkoska, L, Studzinski, D Bealmear, B, Xu, W, Benjamins, J.  Cytokines regulate neuronal gene expression: Differential effects of Th1, Th2 and monocyte/macrophage cytokines. J Neuroimmunol 238:19-33, 2011

4. Lisak, RP, Benjamins, JA, Nedelkoska, L, Barger, J, Ragheb, S, Fan, B, Ouamara N, Johnson, TA, Rajasekharan, S, Bar-Or, A. Secretory products of multiple sclerosis B cells are cytotoxic to oliogdendroglia in vitro, J Neuroimmunol 246:85-95, 2012

5. Benjamins, JA, Nedelkoska, L, Bealmear, B, Lisak, RP. ACTH protects mature oligodendroglia from excitotoxic and inflammation-related damage in vitro. Glia 61:1206-1217, 2013

6. Lisak, RP, Nedelkoska, L, Benjamins, JA. Effects of dextromethorphan on glial cell function: Proliferation, maturation and protection from cytotoxic molecules. Glia 62:751-762, 2014

7. Benjamins, J, Nedlekoska, L, Lisak, R. ACTH 1-39 promotes proliferation and differentiation of olgodendroglial progenitor cells and protects from excitotoxic and inflammation-related damage. J Neurosci Res 92:1243-1251, 2014

8. Lisak, R, Nedelkoska, L, Bealmear, B, Benjamins, J. Melanocortin receptor agonist ACTH 1-39 protects rat forebrain neurons from apoptotic, excitotoxic and inflammation-related damage. Exp Neurol 273:161-167, 2015

9. Lisak, RP, Nedelkoska, L, Benjamins, JA, Schalk, D, Bealmear, B, Touil, H, LI, R, Muirhead, G, Bar-Or, A. B cells from patients with multiple sclerosis induce cell death via apoptosis in neurons in vitro  J Neuroimmunol 309:88-99, 2017

10. Benjamins, JA, Nedelkoska, L, Lisak, RP. Melanocortin receptor subtypes are expressed on cells in the oligodendroglial lineage and signal ACTH protection. J Neurosci Res 96:427-435, 2018;  ePub 2017 Sep 6

11. Lisak, RP, Nedelkoska, L, Benjamins, JA. Sigma-1 receptor agonists as potential protective therapies in multiple sclerosis. J Neuroimmunol  342:577188, 2020 ePub doi.org/10.1016/jneuroim.2020577188

12. Lisak, RP, Nedelkoska, L, Benjamins, JA. Muscarinic receptors mediate oligodendroglial protection by sigma-1 receptor agonist ANAVEX2-73. ACTRIMS Forum 2020 West Palm Beach, FL Mult Scler (on line)

Immune-mediated diseases of the Peripheral Nervous System

Immune mediated demyelinating diseases of the peripheral nervous system (PNS) while not common constitute an important group of diseases. In this era of excellent hygiene and vaccinations to prevent and reduce infections that directly affect the nervous system, Guillain Barre Syndrome (GBS), an acute disease of the PNS, is one of the most common neuropathies causing paralysis including weakness of the facial muscles, muscle involved in swallowing and speaking and in some instances difficulty or even inability to breathe.  While many patients recover from this syndrome, many are left with varying degrees of deficits including weakness, pain and fatigue.  In the United States and in most other developed countries a demyelinating form of the GBS, acute inflammatory demyelinating polyradiculoneuropathy (AIDP) is the most common type of GBS and in AIDP myelin and the Schwann cell which is the cell of the PNS that produces and maintains myelin, are the target of an immune attack with no known etiology and with uncertainty of the mechanisms causing demyelination and recovery, called remyelination. Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and its variants are more progressive and in many cases difficult to treat. Therefore, we need to know more about the interactions between immune system and its effector molecules and the Schwann cells and PNS myelin.

Our work in inflammatory immune-mediated demyelinating and other autoimmune neuropathies examines both the interactions of immune system mediators, antibodies as well as products of T cells and monocyte/macrophages, with Schwann cells, the myelin forming cells of the peripheral nervous system (PNS), using in vitro (tissue culture) and in vivo (animal models) experiments, as well as studies of patients including the first study to demonstrate that plasma exchange was an effective treatment for GBS. Our current 'wet bench' research work is focused on in vitro expression and function of melanocortin receptors (MCRs) on Schwann cells. Our data seem to indicate the activation of MCRs increase proliferation of Schwann cells as well as increasing rate of Schwann cell maturation. Both of these would be beneficial in repair in inflammatory and genetic demyelinating neuropathies as well as in trauma to the PNS. We are also involved in a clinical trial to determine if lowering serum IgG  levels by blocking the neonatal Fc receptor (FcRn) is an effective therapy in CIDP.

Selected Laboratory Studies Related to the PNS

1. Lisak, RP, Bealmear, B, Benjamins, J, Skoff, A. Cytokines inhibit cyclic AMP-upregulation of expression of glycolipids by Schwann Cells in vitro.  Neurology 51:1661-1665,1998.

2. Skoff, AM, Lisak RP, Bealmear, B, Benjamins, JA.  TNF-a and TGF-b act synergistically to kill Schwann cells.  J. Neurosci Res 53:747-756, 1998.

3. Skundric, DS, Lisak, RP, Rhoui, M, Kieseier, BC, Jung, S, Hartung, HP.  Schwann cell specific regulation of IL-1 and IL-1Ra during EAN: possible relevance for immune regulation.  J Neuroimmunol 116:74-82, 2001.

4. Lisak, RP. Cytokines and chemokines in inflammatory demyelinating neuropathies. Clin Exper Neuroimmunology 1:153-164, 2010

5. Lisak, R, Bealmear, B, Benjamins, JA. Schwann cell differentiation inhibits interferon-gamma induction of major histocompatibility complex class II and intercellular adhesion molecule-1. J Neuroimmunology 295-296:93-99, 2016

Myasthenia gravis

Acquired myasthenia gravis (MG) is a disease in which the immune system produces antibodies (autoantibodies) that are directed against molecules of the patients own neuromuscular junction (NMJ). The NMJ is where the peripheral nerves signal the muscle to contract and patients with MG develop weakness with symptoms that include double vision, drooping eye lids, weakness of the arms and legs, trouble swallowing, chewing, speaking and breathing. While death from MG is no longer common, persistent weakness is common. Additionally, many of the treatments used in patients with MG suppress the immune system causing increase in infections, as well as having many other side effects. Thus we need to understand more about how the autoantibodies attack the NMJ and to develop additional therapies for the treatment of MG.

Our current research related to myasthenia gravis is currently more heavily weighted towards clinical trials as well as collaborating with other institutions to characterize clinical phenotypes of patients with more recently describe autoantibodies directed at other molecules expressed at the neuromuscular junction.

Selected Studies Related to MG

1. Ragheb, S, Lisak, R, Lewis, R, Van Stavern, G, Gonzales, F, Simon, K. a potential role for B-cell activating factor in the pathogenesis of autoimmune myasthenia gravis. Arch Neurol 65:11358-1362, 2008.

2. Zhang, B, Tzartos, JS, Belimezi, M, Ragheb, S, Bealmear, B, Lewis, RA, Xiong, W-C, Lisak, RP, Tzartos, SJ.       Autoantibodies to LRP4 in double seronegative myasthenia gravis patients. Arch Neurol 69:445-451, 2012.

3. Berrih-Aknin, S, Ragheb, S, le Panse, R, Lisak, R.Ectopic germinal centers, BAFF and anti-B cell therapy in myasthenia gravis. Autoimmunity Rev Epub 2013/03/30.

4. Zhang, B, Shen, C, Bealmear, B, Ragheb, S, Lewis, RA, Lisak, RP, Mei, L. Autoantibodies to agrin in myasthenia gravis patients. PLos One DOI:10.1371/journal.pone.0091816, March 14, 2014.

5. Lisak, RP, Barcellos, L. New insights into the genetics of autoimmune myasthenia gravis: An evolving story. JAMA Neurol 72:386-387, 2015.

6. Howard, JF, Jr, Utsugisawa, K, Benatar, M, Murai, H, Barohn, RJ,Illa, I, Jacob, S, Vissing, J, Burns, TM, Kissel, JT, Muppidi, S, Nowak, RJ, Wang, JJ, Mantegazza, R.  REAGIN Study Group (Lisak R, memer, Wayne State University PI, listed as author by abstracting services). Safety and efficacy of eclulizumab in anti-acetylcholine receptor antibody-positive refractory generalised myasthenia gravis (REGAIN): a phase 3, randomized, double-blind, placebo-controlled, multicentre study.  Lancet Neurol 16: 976-986, 2017.

7. Ruff, R, Lisak RP.  Nature and action of antibodies in myasthenia gravis. Neurol Clin 36:275-291, 2018.