Jo-1 Antibodies From Myositis Induce Complement-Dependent Cytotoxicity and TREM-1 Upregulation in Muscle Endothelial Cells.

BACKGROUND AND OBJECTIVES: Muscle microangiopathy due to dysfunction of endothelial cells because of inflammation is a critical hallmark of dermatomyositis (DM); however, its pathomechanism remains unclear. The aim of this study was to evaluate the effect of immunogloblin G (IgG) from patients with idiopathic inflammatory myopathies (IIM) on muscle endothelial cells in vitro. METHODS: Using a high-content imaging system, we analyzed whether IgG purified from sera from patients with IIM (n = 15), disease controls (DCs: n = 7), and healthy controls (HCs: n = 7) can bind to muscle endothelial cells and induce complement-dependent cellular cytotoxicity. RESULTS: IgGs from Jo-1 antibody myositis could bind to muscle endothelial cells and caused complement-dependent cell cytotoxicity. RNA-seq demonstrated the upregulation of genes associated with tumor necrosis factor (TNF)-α, triggering receptor expressed on myeloid cells-1 (TREM-1), CD25, and mitochondria pathways after exposure to IgG from the Jo-1, signal recognition particle (SRP), and polymyositis (PM) groups. The high-content imaging system showed that TREM-1 expression in the Jo-1, SRP, and PM groups was increased in comparison with DCs and HCs and that the TNF-α expression in the Jo-1 group was higher in comparison with the SRP, PM, DC, and HC groups. The expression of TREM-1 was observed in biopsied capillaries and the muscle membrane from patients with Jo-1 and in biopsied muscle fiber and capillaries from patients with DM and SRP. The depletion of Jo-1 antibodies by IgG of patients with Jo-1 antibody myositis reduced the Jo-1 antibody-induced complement-dependent cellular cytotoxicity in muscle endothelial cells. DISCUSSION: Jo-1 antibodies from Jo-1 antibody myositis show complement-dependent cellular cytotoxicity in muscle endothelial cells. IgGs from patients with Jo-1, SRP, and DM increase the TREM-1 expression in endothelial cells and muscles.

[Clinical features of 8 patients with multifocal motor neuropathy in the long-term follow-up].

OBJECTIVE: To clarify the clinical and long-term characteristics of multifocal motor neuropathy (MMN). METHODS: We retrospectively evaluated data from 8 consecutive MMN patients in Yamaguchi University Hospital from 2005 to 2020. Clinical information including dominant hand, occupations, hobbies, nerve conduction data, protein level in cerebrospinal fluid (CSF), responsiveness to intravenous immunoglobulin (IVIg) therapy as initial therapy as well as maintenance therapy were collected. RESULTS: Unilateral upper limb was initially affected in all patients and a dominant upper extremity was affected in six of them. Seven patients had occupations or hobbies which were associated with overuse of their dominant upper extremity. CSF protein level was normal or slightly elevated. Nerve conduction studies showed conduction blocks in 4 cases. Effectiveness of IVIg treatment as initial therapy was observed in all patients. Maintenance therapy was not needed in 2 patients because of mild symptoms with stable clinical course. Long-term maintenance therapy with immunoglobulin was effective in 5 patients during the follow-up period. CONCLUSION: Dominant upper extremity was frequently affected and most patients had job or habit associated with its overuse, suggesting that physical overload induces inflammation or demyelination in MMN. IVIg was commonly effective as both introduction and long-term maintenance therapies. Complete remission was achieved after several IVIg treatments in some patients.

Autocrine TNF-α Increases Penetration of Myelin-Associated Glycoprotein Antibodies Across the Blood-Nerve Barrier in Anti-MAG Neuropathy.

BACKGROUND AND OBJECTIVES: Deposition of myelin-associated glycoprotein (MAG) immunoglobulin M (IgM) antibodies in the sural nerve is a key feature in anti-MAG neuropathy. Whether the blood-nerve barrier (BNB) is disrupted in anti-MAG neuropathy remains elusive.We aimed to evaluate the effect of sera from anti-MAG neuropathy at the molecular level using our in vitro human BNB model and observe the change of BNB endothelial cells in the sural nerve of anti-MAG neuropathy. METHODS: Diluted sera from patients with anti-MAG neuropathy (n = 16), monoclonal gammopathies of undetermined significance (MGUS) neuropathy (n = 7), amyotrophic lateral sclerosis (ALS, n = 10), and healthy controls (HCs, n = 10) incubated with human BNB endothelial cells to identify the key molecule of BNB activation using RNA-seq and a high-content imaging system, and exposed with a BNB coculture model to evaluate small molecule/IgG/IgM/anti-MAG antibody permeability. RESULTS: RNA-seq and the high-content imaging system showed the significant upregulation of tumor necrosis factor (TNF-α) and nuclear factor-kappa B (NF-κB) in BNB endothelial cells after exposure to sera from patients with anti-MAG neuropathy, whereas the serum TNF-α concentration was not changed among the MAG/MGUS/ALS/HC groups. Sera from patients with anti-MAG neuropathy did not increase 10-kDa dextran or IgG permeability but enhanced IgM and anti-MAG antibody permeability. Sural nerve biopsy specimens from patients with anti-MAG neuropathy showed higher TNF-α expression levels in BNB endothelial cells and preservation of the structural integrity of the tight junctions and the presence of more vesicles in BNB endothelial cells. Neutralization of TNF-α reduces IgM/anti-MAG antibody permeability. DISCUSSION: Sera from individuals with anti-MAG neuropathy increased transcellular IgM/anti-MAG antibody permeability via autocrine TNF-α secretion and NF-κB signaling in the BNB.

[Acute sarcoid myopathy and neuropathy aggravated by ustekinumab administration in an elderly woman with psoriasis and systemic sarcoidosis].

A 72-year old woman, who had a history of psoriasis and psoriatic arthritis from age of 69, was admitted because of acute progression of dyspnea and generalized muscle weakness after initiation of ustekinumab. She had been diagnosed as having lung and eye sarcoidosis ten months before admission. Nerve conduction studies revealed multiple mononeuropathy and needle electromyography showed myogenic changes with spontaneous activities. Muscle pathology showed non-caseating epithelioid granuloma and high expression of HLA-class I in myofibers. Diagnosis of sarcoid myopathy and neuropathy aggravated by ustekinumab was made, and ustekinumab administration was discontinued, resulting in slight improvement of her respiratory and neuro-muscular symptoms, but her symptoms remained severely disabled. Treatment with oral steroids further improved her clinical symptoms and she became able to walk independently. We considered that ustekinumab inhibited IL-12 and IL-23 signaling, which caused an imbalance in Th1/Th17 differentiation and activation of Th1 cell differentiation, thereby promoting the development of sarcoid myopathy and neuropathy.

[Clinical and long-term characteristics of the subtypes of chronic inflammatory demyelinating polyneuropathy].

OBJECTIVE: To clarify the clinical and long-term characteristic of each subtype of chronic inflammatory demyelinating polyneuropathy (CIDP). METHODS: We evaluated data from 30 consecutive CIDP patients who met the criteria proposed by the European Federation of Neurological Societies and the Peripheral Nerve Society. RESULTS: Patients were classified as having typical CIDP (t-|CIDP) (10/30, 33%), multifocal acquired demyelinating sensory and motor (MADSAM) (12/30, 40%), DADS (4/30, 13%), sensory CIDP (3/30, 10%) or motor CIDP (1/30, 3%). Nerve conduction studies showed more prolonged distal motor latencies/F-wave latencies and slower motor nerve conduction in the typical CIDP group than in the MADSAM group. Intravenous immunoglobulin (IVIg) was effective in 80% (8/10) of t-|CIDP, 100% (12/12) of MADSAM, 100% (4/4) of DADS, and 100% (3/3) of sensory CIDP cases. Maintenance therapy with immunoglobulin was administered in patients with t-|CIDP (5/10, 50%), MADSAM (9/12, 75%), DADS (1/4, 25%), and sensory CIDP (2/3, 67%). There were no patients with CIDP, in whom CIDP subtype was transformed from the initial diagnosis during five years of follow-up. DISCUSSION: Percentage of MADSAM was the most common phenotype in our cohort of CIDP patients, and IVIg/immunoglobulin maintenance was effective for MADSAM as well as t-|CIDP in contrast to findings from the previous reports.

GRP78 Antibodies Are Associated With Blood-Brain Barrier Breakdown in Anti-Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disorder.

BACKGROUND AND OBJECTIVES: To analyze (1) the effect of immunoglobulin G (IgG) from patients with anti-myelin oligodendrocyte glycoprotein antibody (MOG-Ab)-associated disorder on the blood-brain barrier (BBB) endothelial cells and (2) the positivity of glucose-regulated protein 78 (GRP78) antibodies in MOG-Ab-associated disorders. METHODS: IgG was purified from sera with patients with MOG-Ab-associated disorder in the acute phase (acute MOG, n = 15), in the stable stage (stable MOG, n = 14), healthy controls (HCs, n = 9), and disease controls (DCs, n = 27). Human brain microvascular endothelial cells (BMECs) were incubated with IgG, and the number of nuclear NF-κB p65-positive cells in BMECs using high-content imaging system and the quantitative messenger RNA change in gene expression over the whole transcriptome using RNA-seq were analyzed. GRP78 antibodies from patient IgGs were detected by Western blotting. RESULTS: IgG in the acute MOG group significantly induced the nuclear translocation of NF-κB and increased the vascular cell adhesion molecule 1/intercellular adhesion molecule 1 expression/permeability of 10-kDa dextran compared with that from the stable MOG and HC/DC groups. RNA-seq and pathway analysis revealed that NF-κB signaling and oxidative stress (NQO1) play key roles. The NQO1 and Nrf2 protein amounts were significantly decreased after exposure to IgG in the acute MOG group. The rate of GRP78 antibody positivity in the acute MOG group (10/15, 67% [95% confidence interval, 38%-88%]) was significantly higher than that in the stable MOG group (5/14, 36% [13%-65%]), multiple sclerosis group (4/29, 14% [4%-32%]), the DCs (3/27, 11% [2%-29%]), or HCs (0/9, 0%). Removal of GRP78 antibodies from MOG-IgG reduced the effect on NF-κB nuclear translocation and increased permeability. DISCUSSION: GRP78 antibodies may be associated with BBB dysfunction in MOG-Ab-associated disorder.

[Chronic inflammatory demyelinating polyradiculoneuropathy with myelopathy due to massively enlarged nerve roots].

We report a 77-year-old man who presented with numbness and weakness of the feet bilaterally, that had progressed over 13 years. He was diagnosed with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) on the basis of nerve conduction studies and a sural nerve biopsy; however, he was inadequately treated and his weakness had progressed. At 76 years of age, he developed spasticity in the legs as well as bladder and rectal incontinences. Gd-enhanced MRI revealed severe compression of the cervical cord by massively enlarged nerve roots. A cervical laminectomy was performed to decompress the cervical cord. A fascicular biopsy of the C5 dorsal root showed a prominent lymphocyte infiltration and edema. Repeated methylprednisolone pulse therapy and IVIg ameliorated the weakness. We concluded that the main cause of nerve root hypertrophy in this patient was active inflammation.

[A women with aplastic anemia developed chronic inflammatory demyelinating polyneuropathy].

A 66-year-old female developed chronic inflammatory demyelinating polyneuropathy (CIDP) one year after the diagnosis of aplastic anemia. High-dose intravenous immunoglobulin (IVIg) therapy, followed by IVIg maintenance therapy, rapidly improved her weakness and hyperesthesia in four extremities. In addition, pancytopenia caused by aplastic anemia also improved following IVIg treatment in parallel. This is the first report to show the co-existence of CIDP and aplastic anemia, and a common pathomechanism may be present in these two rare autoimmune disorders.

GRP 78 antibodies are associated with clinical phenotype in neuromyelitis optica.

BACKGROUND: We previously reported the association between blood-brain barrier (BBB) dysfunction and glucose-regulated protein 78 (GRP 78) autoantibodies in neuromyelitis optica (NMO). OBJECTIVE: We clarify whether the BBB-endothelial cell activation induced by immunoglobulin G (IgG) is associated with the clinical phenotype, disease activity, and markers of BBB disruption. METHODS: We purified serum IgG from 24 serum samples from patients with NMO spectrum disorder (NMOSD), who were positive for anti-AQP4 antibodies (longitudinally extensive transverse myelitis [LETM], n = 14; optic neuritis [ON], n = 6; other phenotype, n = 4) and nine healthy controls. IgG was exposed to human brain microvascular endothelial cells (TY10) and the number of nuclear NF-κB p65-positive cells, as a marker of endothelial cell activation, was analyzed using a high-content imaging system. Change in BBB permeability was also measured. The presence of GRP78 autoantibodies was detected by Western blotting. RESULTS: In the LETM group, IgG significantly induced the nuclear translocation of NF-κB p65 in comparison to the ON and healthy control groups. A significant correlation was observed between the number of NF-κB nuclear-positive cells and clinical markers of BBB disruption, including Gd enhancement in spinal MRI and the cerebrospinal fluid/serum albumin ratio. This effect was significantly reduced at the remission phase in the individual NMOSD patients. Furthermore, GRP78 antibody positivity was associated with the LETM phenotype and disease severity in NMOSD patients. CONCLUSION: Endothelial cell activation was associated with the LETM phenotype, clinical markers of BBB disruption and disease activity. These observations may explain the phenotypic differences between the NMOSD subtypes, LETM, and isolated ON.

GRP78 antibodies damage the blood-brain barrier and relate to cerebellar degeneration in Lambert-Eaton myasthenic syndrome.

Lambert-Eaton myasthenic syndrome (LEMS) is an autoimmune disease of the neuromuscular junction caused by autoantibodies binding to P/Q-type voltage-gated calcium channels. Breakdown of the blood-brain barrier and diffusion of cerebellar granule/Purkinje cell-reactive autoantibodies into the CNS are critical for the pathogenesis of paraneoplastic cerebellar degeneration (PCD) with Lambert-Eaton myasthenic syndrome. We recently found evidence that glucose-regulated protein 78 (GRP78) autoantibodies in the plasma of patients with neuromyelitis optica promote the CNS access of AQP4 autoantibodies. In the present study, we investigated whether the GRP78 autoantibodies in PCD-LEMS IgG boost the brain uptake of cerebellar cell-reactive antibodies across the blood-brain barrier and facilitate cerebellar dysfunction. We first evaluated the effects of purified IgG from PCD-LEMS or PCD patients on the blood-brain barrier function in human brain microvascular endothelial cells using a high content imaging system with nuclear factor κB p65 and intracellular adhesion molecule 1 (ICAM1) immunostaining. Next, we identified GRP78 autoantibodies causing blood-brain barrier permeability in PCD-LEMS IgG by co-immunoprecipitation and the living cell-based antibody binding assays. Exposure of brain microvascular endothelial cells to IgG from PCD-LEMS patients induced nuclear factor κB p65 nuclear translocation, ICAM1 upregulation, reduced claudin-5 expression, increased permeability and increased autocrine IL-1ß and IL-8 secretion; the IgG from patients with Lambert-Eaton myasthenic syndrome did not have these effects. We detected GRP78 autoantibodies in the IgG of LEMS-PCD (83.3%, n = 18), but observed fewer in patients with LEMS (6.6%, n = 15) and none were observed in the control subjects (n = 8). The depletion of GRP78 autoantibodies reduced the biological effect of LEMS-PCD IgG on brain microvascular endothelial cells. These findings suggest that GRP78 autoantibodies play a role beyond neuromyelitis optica and that they have direct implications in the phenotypic differences between PCD-LEMS and LEMS.

A case of otitis externa caused by Schizophyllum commune: An approach to antimicrobial stewardship using Gram staining of otorrhea in a medical clinic.

Recently, basidiomycete Schizophyllum commune has been reported as a cause of allergic bronchopulmonary mycosis. However, it is rare as a cause of otitis externa. We experienced a very rare case of otitis externa caused by S. commune in a 68-year-old man with a history of chronic otitis media. We performed Gram staining at the first consultation and follow-up treatment and found fungal cells on the smear and treated him with an appropriate antifungal drug. The results of identification and antifungal susceptibility testing obtained in cooperation with clinical microbiologists at other facilities was very important for future treatment planning decisions. Medical practitioners worldwide should introduce a Gram staining tool into their workflow and cooperate closely with clinical microbiologists to achieve antimicrobial stewardship.

Increased IP-10 production by blood-nerve barrier in multifocal acquired demyelinating sensory and motor neuropathy and multifocal motor neuropathy.

OBJECTIVE: Dysfunction of the blood-nerve barrier (BNB) plays important roles in chronic inflammatory demyelinating polyneuropathy (CIDP) and multifocal motor neuropathy (MMN). The aim of the present study was to identify the candidate cytokines/chemokines that cause the breakdown of the BNB using sera from patients with CIDP and MMN. METHODS: We determined the levels of 27 cytokines and chemokines in human peripheral nerve microvascular endothelial cells (PnMECs) after exposure to sera obtained from patients with CIDP variants (typical CIDP and multifocal acquired demyelinating sensory and motor neuropathy [MADSAM]), MMN and amyotrophic lateral sclerosis (ALS), and healthy controls (HC), using a multiplexed fluorescent bead-based immunoassay system. RESULTS: The induced protein (IP)10 level in the cells in both the MADSAM and MMN groups was markedly increased in comparison with the typical CIDP, ALS and HC groups. The other cytokines, including granulocyte colony-stimulating factor,vascular endothelial growth factor (VEGF) and interleukin-7, were also significantly upregulated in the MADSAM group. The increase of IP-10 produced by PnMECs was correlated with the presence of conduction block in both the MADSAM and MMN groups. CONCLUSION: The autocrine secretion of IP-10 induced by patient sera in PnMECs was markedly upregulated in both the MADSAM and MMN groups. The overproduction of IP-10 by PnMECs leads to the focal breakdown of the BNB and may help to mediate the transfer of pathogenic T cells across the BNB, thereby resulting in the appearance of conduction block in electrophysiological studies of patients with MADSAM and MMN.

Fingolimod promotes blood-nerve barrier properties in vitro.

Objective: The main effect of fingolimod is thought to be functional antagonism of lymphocytic S1P1 receptors and the prevention of lymphocyte egress from lymphoid tissues, thereby reducing lymphocyte infiltration into the nervous system. However, a growing number of reports suggest that fingolimod also has a direct effect on several cell types in the nervous system. Although we previously reported that fingolimod enhances blood-brain barrier (BBB) functions, there have been no investigations regarding the blood-nerve barrier (BNB). In this study, we examine how fingolimod affects the BNB. Methods: An immortalized human peripheral nerve microvascular endothelial cell line (HPnMEC) was used to evaluate BNB barrier properties. We examined tight junction proteins and barrier functions of HPnMECs in conditioned medium with or without fingolimod-phosphate and blood sera from patients with typical chronic inflammatory demyelinating polyneuropathy (CIDP). Results: Incubation with fingolimod-phosphate increased levels of claudin-5 mRNA and protein as well as TEER values in HPnMECs. Conversely, typical CIDP sera decreased claudin-5 mRNA/protein levels and TEER values in HPnMECs; however, pretreatment with fingolimod-phosphate inhibited the effects of the typical CIDP sera. Conclusions: Fingolimod-phosphate directly modifies the BNB and enhances barrier properties. This mechanism may be a viable therapeutic target for CIDP, and fingolimod may be useful in patients with typical CIDP who have severe barrier disruption.

Steroid-responsive demyelinating peripheral neuropathy associated with chronic lymphoproliferative disorders of natural killer cells.

We herein report the findings of a 67-year-old woman with steroid-responsive multiple mononeuropathy associated with chronic natural killer (NK) cell lymphocytosis. The patient developed progressive, asymmetric weakness and numbness in all four extremities in the course of a three-month period. Nerve conduction studies revealed asymmetric demyelination in both the motor and sensory nerves, and a biopsy specimen of the sural nerve showed a conspicuous difference in the demyelination between the neighboring fascicles and the infiltration of NK cells in the endoneurium. We considered the multiple mononeuropathy in this patient to have been caused by NK cell infiltration in the endoneurium, and the observed asymmetry might have been due to differences in the NK cell intrusion among the fascicles. Corticosteroid administration resulted in a rapid neurological, electrophysiological and hematological improvement. The rapid clinical amelioration that was observed after corticosteroid therapy suggested that the neuropathy in this case had been mainly caused by the mechanical compression of the endoneurial NK cells or the inflammatory cytokines that had been released by them.

Establishment of a new conditionally immortalized human skeletal muscle microvascular endothelial cell line.

In skeletal muscle, the capillaries have tight junctions (TJs) that are structurally similar to those in the blood-brain barrier (BBB) and blood-nerve barrier (BNB). Although many findings have been clarified in the territory of BBB and BNB, few have so far examined the TJs of capillaries in the skeletal muscle. In addition, no in vitro human skeletal muscle microvasculature models have been reported thus far. We newly established a new human skeletal muscle microvascular endothelial cell (HSMMEC) line. HSMMECs were isolated from human skeletal muscle and were infected with retroviruses harboring temperature-sensitive SV40 T antigen and telomerase genes. This cell line, termed TSM15, showed a spindle fiber-shaped morphology, an immunoreactivity to anti-factor VIII and anti-VE-cadherin antibodies, and a temperature-sensitive growth. TSM15 cells grew stably for more than 40 passages when they were cultured at 33°C, thereby retaining their spindle fiber-shaped morphology and contact inhibition at confluence. The cells expressed tight junctional molecules such as claudin-5, occludin, and zonula occludens-1, as well as transporters such as a glucose transporter 1. The transendothelial electrical resistance of TSM15 was as high as those of the human brain microvascular endothelial cell line. This novel cell line might facilitate the analyses of the pathophysiology of inflammatory myopathy, such as dermatomyositis, and can improve our understanding of the physiological and biochemical properties of the microvasculature in human skeletal muscle.

Identification of galectin-3 as a possible antibody target for secondary progressive multiple sclerosis.

BACKGROUND: Recent studies have revealed that the disruption of the blood-brain barrier (BBB) might contribute to the induction of neurodegeneration in the progressive stage of multiple sclerosis (MS). OBJECTIVE: We investigated a potential target for the serum auto-antibodies responsible for the BBB impairment in patients with secondary progressive MS (SPMS). METHODS: We identified undetermined target antigens in human brain microvascular endothelial cells (BMECs) that reacted with auto-antibodies in sera from SPMS patients using a proteomic approach. In addition, we examined how the identified auto-antibodies compromise the BBB integrity. RESULTS: We found that 10 of 11 SPMS sera had auto-antibodies against galectin-3, although the patients with other neurological diseases did not have these antibodies. Downregulation of galectin-3 led to elevated intercellular adhesion molecule-1 (ICAM-1) and phospho-nuclear factor-kappa (NFκ) B p65 expression in the BMECs. Exposure to SPMS patients' sera also increased the protein levels of ICAM-1 and phospho-NFκB p65 in BMECs, but these effects induced by anti-galectin-3 immunoreactivity were canceled by the downregulation of galectin-3. CONCLUSION: Galectin-3 is a possible immunological target molecule of the pathogenic auto-antibodies and contributes to the persistent BBB breakdown in patients with SPMS. These antibodies may also serve as a novel biomarker for SPMS.

Markedly increased IP-10 production by blood-brain barrier in neuromyelitis optica.

OBJECTIVE: Severe damage to the blood-brain barrier (BBB) allows anti-aquaporin 4 (AQP4) antibodies to access the astrocytic endfeet in neuromyelitis optica (NMO). In the current study, we identified the pathogenic cytokines/chemokines that are responsible for the BBB malfunction induced by NMO sera. METHODS: We measured the levels of 27 cytokines/chemokines in human brain microvascular endothelial cells (BMECs) after exposure to sera obtained from patients with the acute and stable phases of anti-AQP4 antibody-positive NMO spectrum disorder (NMOSD), multiple sclerosis (MS) patients and healthy controls (HC) using a multiplexed fluorescent bead-based immunoassay system. RESULTS: The induced protein (IP)-10 level in the cells was markedly increased following exposure to acute phase NMOSD sera. Other cytokines/chemokines including interleukin (IL)-6 and monocyte chemotactic protein (MCP)-1 were also significantly increased in the acute NMOSD group compared to both the MS and HC groups. The up-regulation of the IP-10 levels in the cells after exposure to the acute-phase NMOSD sera was also observed using another specified ELISA, and this effect was significantly decreased during the remission phase in the individual NMOSD patients. Furthermore, the increase in the level of IP-10 after exposure to the sera was significantly correlated with the cerebrospinal fluid/serum albumin ratio. CONCLUSIONS: Sera from the acute phase of NMO markedly increased the autocrine secretion of IP-10 by BMECs. The over-production of IP-10 in BMECs may play an important role in the pathogenesis of NMO and may therefore help to mediate the trafficking of T cells expressing its receptor across the BBB.

Fingolimod prevents blood-brain barrier disruption induced by the sera from patients with multiple sclerosis.

OBJECTIVE: Effect of fingolimod in multiple sclerosis (MS) is thought to involve the prevention of lymphocyte egress from lymphoid tissues, thereby reducing autoaggressive lymphocyte infiltration into the central nervous system across blood-brain barrier (BBB). However, brain microvascular endothelial cells (BMECs) represent a possible additional target for fingolimod in MS patients by directly repairing the function of BBB, as S1P receptors are also expressed by BMECs. In this study, we evaluated the effects of fingolimod on BMECs and clarified whether fingolimod-phosphate restores the BBB function after exposure to MS sera. METHODS: Changes in tight junction proteins, adhesion molecules and transendothelial electrical resistance (TEER) in BMECs were evaluated following incubation in conditioned medium with or without fingolimod/fingolimod-phosphate. In addition, the effects of sera derived from MS patients, including those in the relapse phase of relapse-remitting (RR) MS, stable phase of RRMS and secondary progressive MS (SPMS), on the function of BBB in the presence of fingolimod-phosphate were assessed. RESULTS: Incubation with fingolimod-phosphate increased the claudin-5 protein levels and TEER values in BMECs, although it did not change the amount of occludin, ICAM-1 or MelCAM proteins. Pretreatment with fingolimod-phosphate restored the changes in the claudin-5 and VCAM-1 protein/mRNA levels and TEER values in BMECs after exposure to MS sera. CONCLUSIONS: Pretreatment with fingolimod-phosphate prevents BBB disruption caused by both RRMS and SPMS sera via the upregulation of claudin-5 and downregulation of VCAM-1 in BMECs, suggesting that fingolimod-phosphate is capable of directly modifying the BBB. BMECs represent a possible therapeutic target for fingolimod in MS patients.

Sera from patients with multifocal motor neuropathy disrupt the blood-nerve barrier.

OBJECTIVE: In multifocal motor neuropathy (MMN), the destruction of the blood-nerve barrier (BNB) has been considered to be the key step in the disease process. The purpose of the present study was to ascertain whether sera from patients with MMN can open the BNB, and which component of patient sera is the most important for this disruption. METHODS: We evaluated the effects of sera from patients with MMN, patients with amyotrophic lateral sclerosis, and control subjects on the expression of tight junction proteins and vascular cell adhesion molecule-1 (VCAM-1), and on the transendothelial electrical resistance (TEER) in human peripheral nerve microvascular endothelial cells (PnMECs). RESULTS: The sera from patients with MMN decreased the claudin-5 protein expression and the TEER in PnMECs. However, this effect was reversed after application of an anti-vascular endothelial growth factor (anti-VEGF) neutralising antibody. The VEGF secreted by PnMECs was significantly increased after exposure to the sera from patients with MMN. The sera from patients with MMN also increased the VCAM-1 protein expression by upregulating the nuclear factor kappa-B (NF-κB) signalling. The immunoglobulin G purified from MMN sera decreased the expression of claudin-5 and increased the VCAM-1 expression in PnMECs. CONCLUSIONS: The sera from MMN patients may disrupt the BNB function via the autocrine secretion of VEGF in PnMECs, or the exposure to autoantibodies against PnMECs that are contained in the MMN sera. Autoantibodies against PnMECs in MMN sera may activate the BNB by upregulating the VCAM-1 expression, thereby allowing for the entry of a large number of circulating inflammatory cells into the peripheral nervous system.

[Blood-brain barrier and blood-nerve barrier in neuroinflammatory diseases].

The blood-brain barrier (BBB) and blood-nerve barrier (BNB) restrict exchanges of soluble factors and cells between the blood and neural tissue, thus playing a crucial role in the maintenance of central (CNS) and peripheral nervous system (PNS) homeostasis. In neuroinflammatory diseases, disruption of the BBB/BNB is the initial key step in the development of inflammatory lesions. BBB/BNB breakdown during inflammation is related to two main processes: (1) leakage between opposing endothelial cells and alteration of junctional components, and (2) leukocyte extravasation into the CNS or PNS. The control of inflammatory cells and humoral factors such as cytokines at the level of BBB/BNB can develop a novel therapeutic strategy toward the inflammatory/autoimmune nervous system disorders.