MIF contribution to progressive brain diseases.

Progressive brain diseases create a huge social and economic burden on modern societies as a major cause of disability and death. Incidence of brain diseases has a significantly increasing trend and merits new therapeutic strategies. At the base of many progressive brain malfunctions is a process of unresolved, chronic inflammation. Macrophage migration inhibitory factor, MIF, is an inflammatory mediator that recently gained interest of neuro-researchers due to its varied effects on the CNS such as participation of nervous system development, neuroendocrine functions, and modulation of neuroinflammation. MIF appears to be a candidate as a new biomarker and target of novel therapeutics against numerous neurologic diseases ranging from cancer, autoimmune diseases, vascular diseases, neurodegenerative pathology to psychiatric disorders. In this review, we will focus on MIF's crucial role in neurological diseases such as multiple sclerosis (MS), Alzheimer's disease (AD) and glioblastoma (GBM).

Novel therapeutic for multiple sclerosis protects white matter function in EAE mouse model.

Multiple sclerosis (MS) is a chronic demyelinating disease with prominent axon dysfunction. Our previous studies in an MS mouse model, experimental autoimmune encephalomyelitis (EAE), demonstrated that major histocompatibility complex Class II constructs can reverse clinical signs of EAE. These constructs block binding and downstream signaling of macrophage migration inhibitory factors (MIF-1/2) through CD74, thereby inhibiting phosphorylation of extracellular signal-regulated kinase (ERK) activation and tissue inflammation and promoting remyelination. To directly assess the effects of a novel third generation construct, DRhQ, on axon integrity in EAE, we compared axon conduction properties using electrophysiology on corpus callosum slices and optic nerves. By using two distinct white matter (WM) tracts, we aimed to assess the impact of the EAE and the benefit of DRhQ on myelinated and unmyelinated axons as well as to test the clinical value of DRhQ on demyelinating lesions in CC and optic myelitis. Our study found that EAE altered axon excitability, delayed axon conduction and slowed spatiotemporal summation correlated with diffuse astrocyte and microglia activation. Because MS predisposes patients to stroke, we also investigated and showed that vulnerability to WM ischemia is increased in the EAE MS mouse model. Treatment with DRhQ after the onset of EAE drastically inhibited microglial and astrocyte activation, improved functional integrity of the myelinated axons and enhanced recovery after ischemia. These results demonstrate that DRhQ administered after the onset of EAE promotes WM integrity and function, and reduces subsequent vulnerability to ischemic injury, suggesting important therapeutic potential for treatment of progressive MS.

Centella asiatica promotes antioxidant gene expression and mitochondrial oxidative respiration in experimental autoimmune encephalomyelitis.

Centella asiatica (Centella) is a traditional botanical medicine that shows promise in treating dementia based on behavioral alterations seen in animal models of aging and cognitive dysfunction. In order to determine if Centella could similarly improve cognitive function and reduce disease burden in multiple sclerosis (MS), we tested its effects in the neuroinflammatory experimental autoimmune encephalomyelitis (EAE) model of MS. In two independent experiments, C57BL/6J mice were treated following induction of EAE with either a standardized water extract of Centella (CAW) or placebo for 2 weeks. At the dosing schedule and concentrations tested, CAW did not improve behavioral performance, EAE motor disability, or degrees of demyelination. However, CAW-treated mice demonstrated increases in nuclear factor (erythroid-derived 2)-like 2 and other antioxidant response element genes, and increases in mitochondrial respiratory activity. Caw also decreased spinal cord inflammation. Our findings indicate that CAW can increase antioxidant gene expression and mitochondrial respiratory activity in mice with EAE, supporting investigation of the clinical effects of CAW in people with MS.

Pharmacological targeting of coagulation factor XI attenuates experimental autoimmune encephalomyelitis in mice.

Multiple sclerosis (MS) is the most common causes of non-traumatic disability in young adults worldwide. MS pathophysiologies include the formation of inflammatory lesions, axonal damage and demyelination, and blood brain barrier (BBB) disruption. Coagulation proteins, including factor (F)XII, can serve as important mediators of the adaptive immune response during neuroinflammation. Indeed, plasma FXII levels are increased during relapse in relapsing-remitting MS patients, and previous studies showed that reducing FXII levels was protective in a murine model of MS, experimental autoimmune encephalomyelitis (EAE). Our objective was to determine if pharmacological targeting of FXI, a major substrate of activated FXII (FXIIa), improves neurological function and attenuates CNS damage in the setting of EAE. EAE was induced in male mice using murine myelin oligodendrocyte glycoprotein peptides combined with heat-inactivated Mycobacterium tuberculosis and pertussis toxin. Upon onset of symptoms, mice were treated every other day intravenously with anti-FXI antibody, 14E11, or saline. Disease scores were recorded daily until euthanasia for ex vivo analyses of inflammation. Compared to the vehicle control, 14E11 treatment reduced the clinical severity of EAE and total mononuclear cells, including CD11b+CD45high macrophage/microglia and CD4+ T cell numbers in brain. Following pharmacological targeting of FXI, BBB disruption was reduced, as measured by decreased axonal damage and fibrin(ogen) accumulation in the spinal cord. These data demonstrate that pharmacological inhibition of FXI reduces disease severity, immune cell migration, axonal damage, and BBB disruption in mice with EAE. Thus, therapeutic agents targeting FXI and FXII may provide a useful approach for treating autoimmune and neurologic disorders.

PD-L1 is required for estrogen-induced protection against severe EAE in IL-10 deficient mice1.

BACKGROUND: IL-10 knockout (KO) mice can be protected against experimental autoimmune encephalomyelitis (EAE) with low-dose estrogen (E2) treatment similar to wild type (WT) mice, indicating that IL-10 is not required for E2-induced EAE protection. Our previous study demonstrated that E2 treatment induced an increase in programmed death ligands 1 (PD-L1) and 2 (PD-L2) on monocytes and macrophages in the periphery and within the CNS. In this study, we selectively inhibited the function of PD-L1 and PD-L2 to evaluate their critical role in maintaining E2-induced protection against EAE in IL-10-KO mice. METHODS: This study used female IL-10 KO mice pre-treated with either E2 or sham pellets seven days prior to induction of EAE and subsequently treated with Vehicle or antibodies to PD-L1, PD-L2 or respective isotype controls. Mice were scored daily for EAE severity over 21 days post-EAE induction. Cells from the spleen and brain were evaluated by flow cytometry. RESULTS: Differences in EAE severity were assessed in E2 and sham pre-treated IL-10-KO mice treated with α-PD-L1 or α-PD-L2 antibodies over the course of disease compared to treatment with Vehicle or isotype control antibodies. The results revealed real-time development of severe EAE in E2-pre-treated IL-10-KO mice treated with α-PD-L1 but not α-PD-L2 antibodies, mediated in part by increased percentages of activated CD74+CD11b+ myeloid cells in spleen and brain as well as splenic B-cells, T-cells and CD73+ cells. CONCLUSION: These results demonstrate unequivocally that PD-L1 but not PD-L2 was required to retain the inhibitory effects of E2 on clinical EAE scores in female IL-10-KO mice and further implicate the emergence of the MIF/CD74 axis as a contributing pathogenic mechanism.

"Near Cure" treatment of severe acute EAE in MIF-1-deficient female and male mice with a bifunctional MHCII-derived molecular construct.

Our previous studies demonstrated increased serum levels of macrophage migration inhibitory factor (MIF-1) and its homologue, MIF-2, in males during MS progression; and that genetically high-MIF-expressing male subjects with relapsing multiple sclerosis (MS) had a significantly greater risk of conversion to progressive MS than lower-MIF-expressing males and females. However, female MS subjects with severe disease expressed higher levels of CD74, the common MIF-1/MIF-2 receptor, on blood cells. In the murine model of MS, experimental autoimmune encephalomyelitis (EAE), both male and female mice lacking MIF-1 and/or MIF-2 were clinically improved during development of moderately severe disease, thus implicating both homologs as co-pathogenic contributors. The current study using MIF-deficient mice with severe acute EAE revealed a highly significant reduction of EAE scores in MIF-1-deficient females, in contrast to only minor and delayed reduction of clinical signs in MIF-1-deficient males. However, clinical EAE scores and factor expression were strongly suppressed in males and further reduced in females after treatment of WT and MIF-1-, MIF-2- and MIF-1/2-DUAL-deficient female and male mice with a MHCII DRα1-MOG-35-55 molecular construct that competitively inhibits MIF-1 & MIF-2 signaling through CD74 as well as T cell activation. These results suggest sex-dependent differences in which the absence of the MIF-1 and/or MIF-2 genotypes may permit stronger compensatory CD74-dependent EAE-inducing responses in males than in females. However, EAE severity in both sexes could still be reduced nearly to background (a "near cure") with DRα1-MOG-35-55 blockade of compensatory MIF and CD74-dependent factors known to attract peripheral inflammatory cells into the spinal cord tissue.

Genistein Stimulation of White Adipose Tissue Thermogenesis Is Partially Dependent on GPR30 in Mice.

SCOPE: Genistein increases whole body energy expenditure by stimulating white adipose tissue (WAT) browning and thermogenesis. G-Coupled receptor GPR30 can mediate some actions of genistein, however, it is not known whether it is involved in the activation of WAT-thermogenesis. Thus, the aim of the study is to determine whether genistein activates thermogenesis coupled to an increase in WAT browning and mitochondrial activity, in GPR30+/+ and GPR30-/- mice. METHODS AND RESULTS: GPR30+/+ and GPR30-/- mice are fed control or high fat sucrose diets containing or not genistein for 8 weeks. Body weight and composition, energy expenditure, glucose tolerance, and browning markers in WAT, and oxygen consumption rate, 3', 5'-cyclic adenosine monophosphate (cAMP) concentration and browning markers in adipocytes are evaluated. Genistein consumption reduces body weight and fat mass gain in a different extent in both genotypes, however, energy expenditure is lower in GPR30-/- compared to GPR30+/+ mice, accompanied by a reduction in browning markers, maximal mitochondrial respiration, cAMP concentration, and browning markers in cultured adipocytes from GPR30-/- mice. Genistein improves glucose tolerance in GPR30+/+ , but this is partially observed in GPR30-/- mice. CONCLUSION: The results show that GPR30 partially mediates genistein stimulation of WAT thermogenesis and the improvement of glucose tolerance.

Tyrphostin A9 protects axons in experimental autoimmune encephalomyelitis through activation of ERKs.

AIMS: Small molecule compound tyrphostin A9 (A9), an inhibitor of platelet-derived growth factor (PDGF) receptor, was previously reported by our group to stimulate extracellular signal-regulated kinase 1 (ERK1) and 2 (ERK2) in neuronal cells in a PDGF receptor-irrelevant manner. The study aimed to investigate whether A9 could protect axons in experimental autoimmune encephalomyelitis through activation of ERKs. MAIN METHODS: A9 treatment on the protection on neurite outgrowth in SH-SY5Y neuroblastoma cells and primary substantia nigra neuron cultures from the neurotoxin MPP+ were analyzed. Then, clinical symptoms as well as ERK1/2 activation, axonal protection induction, and the abundance increases of the regeneration biomarker GAP-43 in the CNS in the relapsing-remitting experimental autoimmune encephalomyelitis (EAE) model were verified. KEY FINDINGS: A9 treatment could stimulate neurite outgrowth in SH-SY5Y neuroblastoma cells and protect primary substantia nigra neuron cultures from the neurotoxin MPP+. In the relapsing-remitting EAE model, oral administration of A9 successfully ameliorated clinical symptoms, activated ERK1/2, induced axonal protection, and increased the abundance of the regeneration biomarker GAP-43 in the CNS. Interestingly, gene deficiency of ERK1 or ERK2 disrupted the beneficial effects of A9 in MOG-35-55-induced EAE. SIGNIFICANCE: These results demonstrated that small molecule compounds that stimulate persistent ERK activation in vitro and in vivo may be useful in protective or restorative treatment for neurodegenerative diseases.

Microglia and astrocyte involvement in neurodegeneration and brain cancer.

The brain is unique and the most complex organ of the body, containing neurons and several types of glial cells of different origins and properties that protect and ensure normal brain structure and function. Neurological disorders are the result of a failure of the nervous system multifaceted cellular networks. Although great progress has been made in the understanding of glia involvement in neuropathology, therapeutic outcomes are still not satisfactory. Here, we discuss recent perspectives on the role of microglia and astrocytes in neurological disorders, including the two most common neurodegenerative conditions, Alzheimer disease and progranulin-related frontotemporal lobar dementia, as well as astrocytoma brain tumors. We emphasize key factors of microglia and astrocytic biology such as the highly heterogeneic glial nature strongly dependent on the environment, genetic factors that predispose to certain pathologies and glia senescence that inevitably changes the CNS landscape. Our understanding of diverse glial contributions to neurological diseases can lead advances in glial biology and their functional recovery after CNS malfunction.

Brief report: Enhanced DRα1-mMOG-35-55 treatment of severe EAE in MIF-1-deficient male mice.

Macrophage migration inhibitory factor (MIF-1) and its homologue d-dopachrome tautomerase (MIF-2) share the common CD74 receptor and function innately to enhance severity of multiple sclerosis (MS) as well as the experimental autoimmune encephalomyelitis (EAE) model for MS. We previously demonstrated that genetically high-MIF-expressing male subjects with relapsing MS had a significantly greater risk of conversion to progressive MS (PMS) than lower-MIF-expressing males. To expand on this observation, we utilized MIF-1, MIF-2, and MIF-1/2-DUAL-deficient male mice to discern if there would be a greater contribution of these inflammatory factors in EAE mice with severe vs. moderate clinical disease signs. As shown previously, mice deficient in either MIF-1 or MIF-2 each had a ∼25% reduction of moderate EAE compared to WT mice, with significant differences in disease onset and trajectory. However, EAE induction in mice deficient in both MIF-1 and MIF-2 genes did not result in a further reduction in EAE severity. This result suggests that the two MIF homologues were likely affecting the same pathogenic pathways such that each could partially compensate for the other but not in an additive or synergistic manner. However, MIF-1-KO, MIF-2-KO, and MIF-1/2-DUAL-KO mice with severe EAE did not exhibit a significant reduction in cumulative EAE scores compared with WT mice, but the MIF-1-KO and, to a lesser extent, MIF-1/2-DUAL-KO mice did show a significant reduction in daily EAE scores over the last 3 days of observation, and MIF-2-KO mice showed a more modest but still consistent reduction over the same span. Furthermore, deletion of MIF-1 resulted in a massive reduction in the expression of EAE- and Complete Freund's Adjuvant-associated inflammatory factors, suggesting delayed involvement of the MIF/CD74 axis in promoting disease expression. To further explore modulation of MIF-1 and MIF-2 effects on EAE, we treated WT mice with moderate EAE using DRα1-mMOG-35-55, an inhibitor of CD74 that blocks both MIF-1 and MIF-2 action. This treatment reduced ongoing moderate EAE severity in excess of 25%, suggesting efficient blockade of the MIF/CD74 axis in disease-enhancing pathways. Moreover, DRα1-mMOG-35-55 treatment of mice with severe EAE strongly reversed EAE- and CFA-associated expression of inflammatory cytokines and chemokines including Tnf, Ccr7, Ccr6, Ccl8, Cxcr3, and Ccl19 in MIF-deficient mouse genotypes, and also exceeded innate MIF-1 and MIF-2 EAE enhancing effects, especially in MIF-1-KO mice. These results illustrate the therapeutic potential of targeting the disease-enhancing MIF/CD74 pathway in male mice with moderate and severe EAE, with implications for treatment of high-MIF-expressing RRMS human males at risk of conversion to progressive MS as well as those that have already transitioned to PMS.

Major histocompatibility complex Class II-based therapy for stroke.

This review discusses the potential of major histocompatibility complex (MHC) Class II constructs as stroke therapeutics. We focus on the delivery of MHC Class II construct, DRmQ, as a safe and effective treatment for ischemic stroke. DRmQ was observed to attenuate behavioral deficits and decrease microglia activation and proinflammatory cytokines, illustrating its ability to mitigate the secondary cell death following stroke. Similar anti-neuroinflammation treatments, such as transplantation of mesenchymal stem cells and mitochondrial transfers, are briefly discussed to provide further support that sequestration of inflammation stands as a robust therapeutic target for stroke.

Cross-Talk of the CNS With Immune Cells and Functions in Health and Disease.

The immune system's role is much more than merely recognizing self vs. non-self and involves maintaining homeostasis and integrity of the organism starting from early development to ensure proper organ function later in life. Unlike other systems, the central nervous system (CNS) is separated from the peripheral immune machinery that, for decades, has been envisioned almost entirely as detrimental to the nervous system. New research changes this view and shows that blood-borne immune cells (both adaptive and innate) can provide homeostatic support to the CNS via neuroimmune communication. Neurodegeneration is mostly viewed through the lens of the resident brain immune populations with little attention to peripheral circulation. For example, cognition declines with impairment of peripheral adaptive immunity but not with the removal of microglia. Therapeutic failures of agents targeting the neuroinflammation framework (inhibiting immune response), especially in neurodegenerative disorders, call for a reconsideration of immune response contributions. It is crucial to understand cross-talk between the CNS and the immune system in health and disease to decipher neurodestructive and neuroprotective immune mechanisms for more efficient therapeutic strategies.

Sex differences in EAE reveal common and distinct cellular and molecular components.

Experimental autoimmune encephalomyelitis (EAE) is commonly used as an animal model for evaluating clinical, histological and immunological processes potentially relevant to the human disease multiple sclerosis (MS), for which the mode of disease induction remains largely unknown. An important caveat for interpreting EAE processes in mice is the inflammatory effect of immunization with myelin peptides emulsified in Complete Freund's Adjuvant (CFA), often followed by additional injections of pertussis toxin (Ptx) in some strains to induce EAE. The current study evaluated clinical, histological, cellular (spleen), and chemokine-driven processes in spinal cords of male vs. female C57BL/6 mice that were immunized with mouse (m)MOG-35-55/CFA/Ptx to induce EAE; immunized with saline/CFA/Ptx only (CFA, no EAE); or were untreated (Naïve, no EAE). Analysis of response curves utilized a rigorous and sophisticated methodology to parse and characterize the effects of EAE and adjuvant alone vs. the Naive baseline responses. The results demonstrated stronger pro-inflammatory responses of immune cells and their associated cytokines, chemokines, and receptors in male vs. female CFA and EAE mice that appeared to be offset partially by increased percentages of male anti-inflammatory, regulatory and checkpoint T cell, B cell, and monocyte/macrophage subsets. These sex differences in peripheral immune responses may explain the reduced cellular infiltration and differing chemokine profiles in the Central Nervous System (CNS) of male vs. female CFA immunized mice and the reduced CNS infiltration and demyelination observed in male vs. female EAE groups of mice that ultimately resulted in the same clinical EAE disease severity in both sexes. Our findings suggest EAE disease severity is governed not only by the degree of CNS infiltration and demyelination, but also by the balance of pro-inflammatory vs. regulatory cell types and their secreted cytokines and chemokines.

Spleen participation in partial MHC class II construct neuroprotection in stroke.

Pathological progression of stroke in the peripheral and central nervous systems (PNS and CNS) is characterized by multiple converging signalling pathways that exacerbate neuroinflammation-mediated secondary cell death. This creates a need for a novel type of immunotherapy capable of simultaneously lowering the synergistic inflammatory responses in the PNS and CNS, specifically the spleen and brain. Previously, we demonstrated that partial major histocompatibility complex (MHC) class II constructs can be administered subcutaneously to promote histological and behavioural effects that alleviate common symptoms found in a murine model of transient stroke. This MHC class II manipulates T cell cytokine expression in both PNS and CNS, resulting in dampened inflammation. In our long-standing efforts towards translational research, we recently demonstrated that a potent next generation mouse-based partial MHC class II construct named DRmQ (DRa1L50Q -mMOG-35-55) similarly induces neuroprotection in stroke rats, replicating the therapeutic effects of the human homolog as DRhQ (DRa1L50Q -human (h)MOG-35-55) in stroke mice. Our preclinical studies showed that DRmQ reduces motor deficits, infarct volume and peri-infarct cell loss by targeting inflammation in this second species. Moreover, we provided mechanistic support in both animal studies that partial MHC class II constructs effectively modulate the spleen, an organ which plays a critical role in modulating secondary cell death. Together, these preclinical studies satisfy testing the constructs in two stroke models, which is a major criterion of the Stroke Therapy Academic Industry Roundtable (STAIR) criteria and a key step in effectively translating this drug to the clinic. Additional translational studies, including dose-response and larger animal models may be warranted to bring MHC class II constructs closer to the clinic.

A Novel Partial MHC Class II Construct, DRmQ, Inhibits Central and Peripheral Inflammatory Responses to Promote Neuroprotection in Experimental Stroke.

Recognizing that the pathologic progression of stroke is closely associated with aberrant immune responses, in particular the activation of peripheral leukocytes, namely T cells, we hypothesized that finding a treatment designed to inhibit neuroantigen-specific T cells and block cytotoxic monocytes and macrophages may render therapeutic effects in stroke. We previously reported that subcutaneous administration of partial MHC class II constructs promote behavioral and histological effects in stroke mice by centrally promoting a protective M2 macrophage/microglia phenotype in the CNS and peripherally reversing stroke-associated splenic atrophy. Here, we employed a second species using adult Sprague-Dawley rats exposed to the middle cerebral artery occlusion stroke model and observed similar therapeutic effects with a mouse partial MHC class II construct called DRmQ, as evidenced by reductions in stroke-induced motor deficits, infarcts, and peri-infarct cell loss and neuroinflammation. More importantly, we offered further evidence of peripheral sequestration of inflammation at the level of the spleen, which was characterized by attenuation of stroke-induced spleen weight reduction and TNF-ɑ and IL-6 upregulation. Collectively, these results satisfy the Stroke Therapy Academic Industry Roundtable criteria of testing a novel therapeutic in a second species and support the use of partial MHC class II constructs as a stroke therapeutic designed to sequester both central and peripheral inflammation responses in an effort to retard, or even halt, the neuroinflammation that exacerbates the secondary cell death in stroke.

Estrogen-induced compensatory mechanisms protect IL-10-deficient mice from developing EAE.

BACKGROUND: IL-10 knockout (KO) mice are protected from experimental autoimmune encephalomyelitis (EAE) with low-dose estrogen (E2) treatment similar to wild-type (WT) mice. Previous studies have demonstrated a decrease in tumor necrosis factor in all E2-treated groups, which led to the protection of the mice. METHODS: This study used IL-10 KO mice and WT mice treated either with E2 or sham pellets 7 days prior to induction of EAE. Mice were observed for 21 days post-immunization. The spleen, inguinal lymph nodes, and brain were evaluated by flow cytometry. Spinal cords were evaluated using a cytokine/chemokine array, RT-PCR, and histology. RESULTS: This study demonstrates that E2 treatment induced three heightened regulatory mechanisms that potentially protect IL-10 KO mice from EAE: (1) an increase in programmed death-ligands 1 and 2 on monocytes and macrophages in the periphery and within the CNS; (2) an increase in CD73 in the inflamed CNS, which can increase the production of the anti-inflammatory molecule adenosine; and (3) a decrease in CD4+CD25+FoxP3+ regulatory T cells in the spleen. Together, these factors comprise an alternative compensatory mechanism that significantly downregulates key pro-inflammatory cytokine, chemokine, and chemokine receptor genes which are enhanced in the spinal cord of IL-10 KO mice. This group of E2-treated mice remained asymptomatic after EAE challenge similar to E2-treated WT mice, despite their having more T and B lymphocytes in the brain, and modestly increased demyelination in the spinal cord. CONCLUSION: These results indicate that previously unrecognized compensatory mechanisms of EAE protection are stimulated by E2 in the absence of IL-10, which can provide disease protection comparable to the IL-10-dependent effects induced by E2 in WT mice.

Sex differences in the therapeutic effects of anti-PDL2 neutralizing antibody on stroke.

Inflammation involving migration of immune cells across the damaged blood-brain barrier (BBB), activation of resident innate microglia and production of inflammatory humoral mediators such as cytokines and chemokines play a critical role in the pathogenesis of ischemic stroke. Cell-cell signaling involved in the process also includes checkpoint interaction between programmed death receptor (PD1) and programmed death ligands, PDL1 and PDL2. Based on our previous studies showing reduced MCAO infarct volumes in PDL2 deficient mice, we evaluated the ability of anti-PDL2 mAb to treat MCAO in male and female C57BL/6 mice. We found that anti-PDL2 neutralizing antibody treatment of MCAO significantly reduced infarct volumes in male mice but had no protective effects in female mice even at a 5-fold increased dose of anti-PDL2 mAb. The protection in male mice was likely mediated by reduced percentages in the spleen of PDL2+CD19+ B cells, PDL1+CD4+ T cells and CD86+CD11b+ macrophages in concert with reduced expression of PDL1 and TNFα and continued expression of CD206, in the injured ipsilateral brain hemisphere. The lack of a therapeutic benefit of anti-PDL2 on stroke-induced infarct volumes in female mice was reflected by no detectable reduction in expressed PDL2 or PDL1 and an increased frequency of Th1 and Th17 pro-inflammatory T cell subsets in the spleen, an effect not seen in PDL2 mAb treated males. This result potentially limits the utility of anti-PDL2 mAb therapy in stroke to males but underscores the importance of meeting the STAIR requirements for development of new stroke therapies for both sexes.

A novel neurotherapeutic for multiple sclerosis, ischemic injury, methamphetamine addiction, and traumatic brain injury.

Neurovascular, autoimmune, and traumatic injuries of the central nervous system (CNS) all have in common an initial acute inflammatory response mediated by influx across the blood-brain barrier of activated mononuclear cells followed by chronic and often progressive disability. Although some anti-inflammatory therapies can reduce cellular infiltration into the initial lesions, there are essentially no effective treatments for the progressive phase. We here review the successful treatment of animal models for four separate neuroinflammatory and neurodegenerative CNS conditions using a single partial MHC class II construct called DRa1-hMOG-35-55 or its newest iteration, DRa1(L50Q)-hMOG-35-55 (DRhQ) that can be administered without a need for class II tissue type matching due to the conserved DRα1 moiety of the drug. These constructs antagonize the cognate TCR and bind with high affinity to their cell-bound CD74 receptor on macrophages and dendritic cells, thereby competitively inhibiting downstream signaling and pro-inflammatory effects of macrophage migration inhibitory factor (MIF) and its homolog, D-dopachrome tautomerase (D-DT=MIF-2) that bind to identical residues of CD74 leading to progressive disease. These effects suggest the existence of a common pathogenic mechanism involving a chemokine-driven influx of activated monocytes into the CNS tissue that can be reversed by parenteral injection of the DRa1-MOG-35-55 constructs that also induce anti-inflammatory macrophages and microglia within the CNS. Due to their ability to block this common pathway, these novel drugs appear to be prime candidates for therapy of a wide range of neuroinflammatory and neurodegenerative CNS conditions.

Increased CD74 binding and EAE treatment efficacy of a modified DRα1 molecular construct.

Multiple sclerosis (MS) is a demyelinating and degenerative disease of the central nervous system (CNS) with a strong inflammatory component that affects more than 2 million people worldwide (and at least 400,000 in the United States). In MS, macrophage migration inhibitory factor (MIF) and D-dopachrome tautomerase (D-DT) enhance the inflammatory event as a result of their interaction with their cognate receptor CD74. Therefore, the search for new agents aimed at blocking this interaction is critical for therapeutic purposes and will be of paramount importance for the treatment of MS. DRα1-MOG-35-55 constructs have been demonstrated to be effective in the treatment of experimental autoimmune encephalomyelitis (EAE) a mouse model for MS. This effect is directly correlated with the binding to its cell surface receptor, CD74, apparently preventing or blocking the binding of two inflammatory factors, MIF and D-DT. Here we report that a single amino acid substitution (L50Q) in the DRα1 domain of the human and mouse DRα1-MOG-35-55 constructs (notated as DRhQ and DRmQ, respectively) possessed increased affinity for CD74, a greater capacity to block MIF binding, the ability to inhibit pERK1/2 signaling and increased therapeutic activity in mice with EAE. These data suggest that binding affinity for CD74 could serve as an in vitro indicator of biological potency of DRhQ and thus support its possible clinical utility as an effective therapy for MS and perhaps other diseases in which there is an inflammatory reaction driven by MIF and D-DT.