Han Lab Publications

Abstract

X-linked adrenoleukodystrophy (ALD) is caused by mutations in ABCD1, a peroxisomal gene. More than half of males with an ABCD1 mutation develop inflammatory cerebral demyelination (cALD), but underlying mechanisms remain unknown and therapies are limited. We sought to develop and characterize a mouse model of cALD to facilitate study of disease mechanisms and therapy development.We used immunoassays and immunohistochemistry to assess novel (interleukin 18 [IL-18]) and established molecular markers in cerebrospinal fluid (CSF) and postmortem brain tissue from cALD patients. We generated a cALD phenotype in Abcd1-knockout mice using a 2-hit method that combines cuprizone and experimental autoimmune encephalomyelitis models. We then used magnetic resonance imaging (MRI) and immunohistochemistry to assess the fidelity of cALD molecular markers in the mice.Human and mouse cALD lesions shared histologic features of myelin phagocytosis, myelin loss, abundant microglial activation, T and B-cell infiltration, and astrogliosis. Compared to wild-type controls, Abcd1-knockout mice displayed more cerebral demyelination, blood-brain barrier disruption, and perivascular immune cell infiltration. This enhanced inflammatory response was associated with higher levels of fibrin deposition, oxidative stress, demyelination, and axonal injury. IL-18 immunoreactivity co-localized with perivascular monocytes/macrophages in both human and mouse brain tissue. In cALD patients, CSF IL-18 levels correlated with MRI lesion severity.Our results suggest loss of Abcd1 function in mice predisposes to more severe blood-brain barrier disruption, cerebral inflammation driven by the infiltration of peripheral immune cells, demyelination, and axonal damage, replicating human cALD features. This novel mouse model could shed light on cALD mechanisms and accelerate cALD therapy development. ANN NEUROL 2024.

View details for DOI 10.1002/ana.27117

View details for PubMedID 39467011

View details for Web of Science ID 001324906903494

View details for Web of Science ID 001324906902302

View details for Web of Science ID 001324906902075

View details for Web of Science ID 001324906903445

View details for DOI 10.1212/WNL.0000000000209215

View details for Web of Science ID 001262358400001

Abstract

The dry mass and the orientation of biomolecules can be imaged without a label by measuring their permittivity tensor (PT), which describes how biomolecules affect the phase and polarization of light. Three-dimensional (3D) imaging of PT has been challenging. We present a label-free computational microscopy technique, PT imaging (PTI), for the 3D measurement of PT. PTI encodes the invisible PT into images using oblique illumination, polarization-sensitive detection and volumetric sampling. PT is decoded from the data with a vectorial imaging model and a multi-channel inverse algorithm, assuming uniaxial symmetry in each voxel. We demonstrate high-resolution imaging of PT of isotropic beads, anisotropic glass targets, mouse brain tissue, infected cells and histology slides. PTI outperforms previous label-free imaging techniques such as vector tomography, ptychography and light-field imaging in resolving the 3D orientation and symmetry of organelles, cells and tissue. We provide open-source software and modular hardware to enable the adoption of the method.

View details for DOI 10.1038/s41592-024-02291-w

View details for PubMedID 38890427

View details for PubMedCentralID 6922317

View details for Web of Science ID 001313316200178

View details for Web of Science ID 001312227704062

Abstract

Antipsychotic medications (APMs) and selective serotonin reuptake inhibitors (SSRIs) are frequently utilized in patients with neuroinflammatory disorders, such as autoimmune encephalitis and multiple sclerosis (MS). This retrospective study investigates how in-hospital treatment with APMs and SSRIs in patients with these neuroinflammatory diseases are associated with differences in hospital length-of-stay (LOS) and mortality.We evaluated all the inpatients in the Stanford University Hospital from 2008 to 2023 diagnosed with either non-infectious encephalitis or MS and subdivided them into those who did or did not receive APMs or SSRIs while hospitalized. We then analyzed whether hospital LOS and mortality differed with these medications.Among inpatients with non-infectious encephalitis (n = 114), those who were exposed to APMs had a significantly increased mean LOS (11.8 vs 20.9 days, p < 0.01). For inpatients with MS (n = 1095), treatment with an APM was associated with a significant increase in mean LOS (2.8 vs. 7.1, p < 0.00001). When comparing typical to atypical APMs given to subjects with MS, those who received atypical APMs showed a significant increase in LOS (4.3 vs 10.5, p < 0.01), although typical APMs showed significantly increased risk of mortality (p < 0.05). For inpatients with MS and SSRI use, there was a significant increase in mean hospital LOS (3.5 vs 5.3, p < 0.01), with a significant difference found in those who received fluoxetine or citalopram, but not sertraline or escitalopram. Finally, several healthcare disparities were found, including that Black patients were more likely to receive APMs, and those with MS were more likely to receive typical rather than atypical APMs. Conversely, Black patients with MS were less likely to receive SSRI treatment.There was a statistically significant increase in LOS associated with APM use in non-infectious encephalitis and MS, as well as with SSRI use in MS. These data reflect the importance of these medications in these neuroinflammatory disorders and suggest that further investigation into their risks and benefits would be warranted.

View details for DOI 10.1016/j.jocn.2024.04.021

View details for PubMedID 38677201

Abstract

CD19 chimeric antigen receptor (CAR) T-cell therapy has proven highly effective for treating relapsed/refractory mantle cell lymphoma (MCL). However, immune effector cell-associated neurotoxicity syndrome (ICANS) remains a significant concern. This study aimed to evaluate the clinical, radiological, and laboratory correlatives associated with ICANS development following CD19 CAR T-cell therapy in patients with MCL. All patients (n = 26) who received standard of care brexucabtagene autoleucel until July 2022 at our institution were evaluated. Laboratory and radiographic correlatives including brain magnetic resonance imaging (MRI) and electroencephalogram (EEG) were evaluated to determine the clinical impact of ICANS. Seventeen (65%) patients experienced ICANS after treatment, with a median onset on day 6. Ten (38%) patients experienced severe (≥ grade 3) ICANS. All ICANS patients had antecedent cytokine release syndrome (CRS), but no correlation was observed between ICANS severity and CRS grade. 92% of EEGs revealed interictal changes; no patients experienced frank seizures due to ICANS. 86% of severe ICANS patients with post-infusion brain MRIs demonstrated acute neuroimaging findings not seen on pretreatment MRI. Severe ICANS was also associated with higher rates of cytopenia, coagulopathy, increased cumulative steroid exposure, and prolonged hospitalization. However, severe ICANS did not affect treatment outcomes of patients with MCL. Severe ICANS is frequently associated with a range of post-infusion brain MRI changes and abnormal EEG findings. Longer hospitalization was observed in severe ICANS patients, especially those with abnormal acute MRI or EEG findings, but there was no discernible impact on overall treatment response and survival.

View details for DOI 10.1182/bloodadvances.2023011896

View details for PubMedID 38295285

Abstract

Neuromyelitis optica spectrum disorder (NMOSD) is a chronic CNS demyelinating autoimmune disorder targeting the astrocyte antigen aquaporin-4 (AQP4), typically presenting with optic neuritis, transverse myelitis, and brain syndromes. Cognitive dysfunction (CD) in NMOSD is under-recognized and poorly understood. The purpose of this study was to evaluate the prevalence and clinical variables associated with CD in NMOSD.This observational retrospective study with longitudinal follow-up describes a clinical cohort seen in the Collaborative International Research in Clinical and Longitudinal Experience Study in NMOSD. Serial Montreal Cognitive Assessments (MoCAs) were performed upon enrollment and at 6-month intervals to evaluate longitudinal cognitive function relative to demographic and disease-related factors. We used 2-tailed t test, analysis of variance, the χ2 test, linear regression for univariable and adjusted analyses and simultaneous linear regression and mixed-effects model for multivariable analyses.Thirty-four percent (75/219) of patients met criteria for CD (MoCA <26); 29% (64/219) showed mild dysfunction (MoCA 20-26/30), and 5% (11/219) showed moderate (MoCA <20/30) dysfunction. Patients with less neurologic disability and lower pain scores had higher MoCA scores (95% CI 0.24-0.65 and 95% CI 0.09-0.42, respectively). Patients with at least high school education scored higher on the MoCA (95% CI 2.2-5). When comparing patients dichotomized for CD, patients never on rituximab scored higher than patients only treated with rituximab (p < 0.029). There was no significant association between annualized relapse rate, age, sex, disease duration, AQP4 serostatus or brain lesions, and CD. CD was more pronounced among Black than White patients (95% CI -2.7 to -0.7). Multivariable analysis of serial MoCA did not indicate change (p = 0.715). Descriptive analysis of serial MoCA showed 30% (45/150) of patients with worsening MoCA performance had impaired language and verbal recall.To our knowledge, this is the largest study of diverse cohort to investigate CD in patients with NMOSD. Our findings demonstrate 34% of patients with NMOSD experience mild-to-moderate CD, while 30% of patients demonstrated decline on serial testing. The substantial prevalence of CD in this pilot report highlights the need for improved and validated screening tools and comprehensive measures to investigate CD in NMOSD.

View details for DOI 10.1212/WNL.0000000000207965

View details for PubMedID 38165361

View details for DOI 10.1002/ana.27117

Abstract

We sought to create and characterize a mouse model of the inflammatory, cerebral demyelinating phenotype of X-linked adrenoleukodystrophy (ALD) that would facilitate the study of disease pathogenesis and therapy development. We also sought to cross-validate potential therapeutic targets such as fibrin, oxidative stress, and the NLRP3 inflammasome, in post-mortem human and murine brain tissues.ALD is caused by mutations in the gene ABCD1 encoding a peroxisomal transporter. More than half of males with an ABCD1 mutation develop the cerebral phenotype (cALD). Incomplete penetrance and absence of a genotype-phenotype correlation imply a role for environmental triggers. Mechanistic studies have been limited by the absence of a cALD phenotype in the Abcd1-null mouse.We generated a cALD phenotype in 8-week-old, male Abcd1-null mice by deploying a two-hit method that combines cuprizone (CPZ) and experimental autoimmune encephalomyelitis (EAE) models. We employed in vivo MRI and post-mortem immunohistochemistry to evaluate myelin loss, astrogliosis, blood-brain barrier (BBB) disruption, immune cell infiltration, fibrin deposition, oxidative stress, and Nlrp3 inflammasome activation in mice. We used bead-based immunoassay and immunohistochemistry to evaluate IL-18 in CSF and post-mortem human cALD brain tissue.MRI studies revealed T2 hyperintensities and post-gadolinium enhancement in the medial corpus callosum of cALD mice, similar to human cALD lesions. Both human and mouse cALD lesions shared common histologic features of myelin phagocytosis, myelin loss, abundant microglial activation, T and B-cell infiltration, and astrogliosis. Compared to wild-type controls, Abcd1-null mice had more severe cerebral inflammation, demyelination, fibrin deposition, oxidative stress, and IL-18 activation. IL-18 immunoreactivity co-localized with macrophages/microglia in the perivascular region of both human and mouse brain tissue.This novel mouse model of cALD suggests loss of Abcd1 function predisposes to more severe cerebral inflammation, oxidative stress, fibrin deposition, and Nlrp3 pathway activation, which parallels the findings seen in humans with cALD. We expect this model to enable long-sought investigations into cALD mechanisms and accelerate development of candidate therapies for lesion prevention, cessation, and remyelination.

View details for DOI 10.1101/2023.11.07.564025

View details for PubMedID 37986739

View details for PubMedCentralID PMC10659266

View details for Web of Science ID 001091311305114

View details for Web of Science ID 001091311305307

View details for Web of Science ID 001091311305047

View details for Web of Science ID 001053795604033

View details for DOI 10.1212/WNL.0000000000204308

View details for Web of Science ID 001053672100108

View details for DOI 10.1212/WNL.0000000000204140

View details for Web of Science ID 001053672105186

View details for DOI 10.1212/WNL.0000000000204219

View details for Web of Science ID 001053672106241

View details for DOI 10.1212/WNL.0000000000204302

View details for Web of Science ID 001053672102035

Abstract

OBJECTIVE: Neuromyelitis optica spectrum disorders (NMOSD) represent rare autoimmune diseases of the central nervous system largely targeting optic nerve(s) and spinal cord. The present analysis used real-world data to identify clinical and epidemiological correlates of treatment change in patients with NMOSD.METHODS: CIRCLES is a longitudinal, observational study of NMOSD conducted at 15 centers across North America. Patients with≥60days of follow-up and receiving on-study maintenance treatment were evaluated. The mean annual relapse rate (ARR) was estimated using negative binomial models; the likelihood of treatment change was estimated using Cox proportional hazards models. Relapses were included as time-varying covariates to estimate the relationship to treatment change.RESULTS: Of 542 patients included, 171 (31.5%) experienced≥1 relapse on the study and 133 patients (24.5%) had≥1 change in the treatment regimen. Two categories of variables significantly correlated with the likelihood of treatment change: (1) relapse: any on-study relapse (hazard ratio [HR]=2.91; p<0.001), relapse phenotypes (HR range=2.15-5.49; p<0.001), and pre-study ARR>0.75 (HR 2.28; p<0.001); 2) disease phenotype: brain syndrome only vs transverse myelitis involvement at onset (HR 2.44; p=0.008), disease duration<1 vs>5years (HR 1.66; p=0.028), or autoimmune comorbidity (HR 1.55; p=0.015). A subset of these factors significantly correlated with shorter time to first rituximab discontinuation.CONCLUSIONS: In CIRCLES, relapse patterns and disease phenotype significantly correlated with changes in the maintenance treatment regimen. Such findings may facilitate the identification of patients with NMOSD who are likely to benefit from treatment change to reduce relapse risk or disease burden and enhance the quality of life.

View details for DOI 10.1007/s00415-022-11529-6

View details for PubMedID 36565348

View details for Web of Science ID 000867884200308

Abstract

Multiple sclerosis (MS) is an inflammatory-demyelinating disease of the central nervous system (CNS) mediated by aberrant auto-reactive immune responses. The current immune-modulatory therapies are unable to protect and repair immune-mediated neural tissue damage. One of the therapeutic targets in MS is the sphingosine-1-phosphate (S1P) pathway which signals via sphingosine-1-phosphate receptors 1-5 (S1P1-5). S1P receptors are expressed predominantly on immune and CNS cells. Considering the potential neuroprotective properties of S1P signaling, we utilized S1P1-GFP (Green fluorescent protein) reporter mice in the cuprizone-induced demyelination model to investigate in vivo S1P - S1P1 signaling in the CNS. We observed S1P1 signaling in a subset of neural stem cells in the subventricular zone (SVZ) during demyelination. During remyelination, S1P1 signaling is expressed in oligodendrocyte progenitor cells in the SVZ and mature oligodendrocytes in the medial corpus callosum (MCC). In the cuprizone model, we did not observe S1P1 signaling in neurons and astrocytes. We also observed beta-arrestin-dependent S1P1 signaling in lymphocytes during demyelination and CNS inflammation. Our findings reveal beta-arrestin-dependent S1P1 signaling in oligodendrocyte lineage cells implying a role of S1P1 signaling in remyelination.

View details for DOI 10.1007/s10571-022-01245-0

View details for PubMedID 35917044

Abstract

Background: Fingolimod is a sphingosine 1-phosphate receptor modulator approved for relapsing MS. Long-term effects on the immunological profile are not fully understood.Objective: Investigate fingolimod's temporal effects on immune cell subsets, and safety outcomes.Methods: In FLUENT, a 12-month, prospective, non-randomized, open-label, phase IV study, adult participants received fingolimod 0.5 mg/day. Changes in immune cell subsets, anti-John Cunningham virus (JCV) antibody index, and serum neurofilament levels were assessed.Results: 165 fingolimod-naive and 217 participants treated for 2-12 years in routine clinical practice were enrolled. Levels of all monitored peripheral lymphocyte subsets were reduced from month 3 in fingolimod-naive participants. Greatest reductions occurred in naive and central memory CD4+and CD8+T cells, and in naive and memory B cells. Most lymphocyte subset levels remained stable in the continuous fingolimod group. Components of the innate immune system remained within reference ranges. No increase in JCV seropositivity was observed. No single cellular subset correlated with anti-JCV antibody index at any time point. Neurofilament levels remained within healthy adult reference limits throughout. No opportunistic infections were reported; no new or unexpected safety signals were observed.Conclusion: FLUENT provides insights into the utility of immunological profiling to evaluate therapy response and potential infection risk.

View details for DOI 10.1177/20552173221115023

View details for PubMedID 35936922

View details for Web of Science ID 000894020500455

Abstract

INTRODUCTION: A multidisciplinary panel of physicians was convened to gain understanding of the relationship between thromboembolic events (TEs) and immune-mediated diseases (IMDs).The primary objective of the panel was to assess areas of consensus on the IMD most prone to TE as well as modifiable and unmodifiable factors that might exacerbate or mitigate the risk of TEs.METHODS: Thirteen nationally recognized physicians were selected based on their contributions to guidelines, publications, and patient care. The modified Delphi panel consisted of four rounds of engagement: (1) a semi-structured interview, (2) an expert panel questionnaire, (3) an in-person panel discussion, and (4) a consensus statement survey.RESULTS: Ulcerative colitis and Crohn's disease were identified as two of four IMDs with the highest TE risk. Consensus was reached on several non-modifiable and modifiable characteristics of high-risk. Approaches to reduce TE incidence were identified such as altering treatment, requiring the monitoring of patients for TEs, and modifying patient behaviors. Janus kinase inhibitors and corticosteroids were identified as therapies that required further evaluation given their potential TE risk.DISCUSSION: The panel reached a consensus that several IMDs are at an elevated risk of TEs. Physicians are unable to control most patient level risk factors but can control the therapies being used. Consequently, physicians should consider the specific IMD, be aware of TE risk factors, and take into account risk factors in selecting the therapies to optimally manage their conditions and to reduce the risk of TEs in this population.

View details for DOI 10.1080/03007995.2021.1932450

View details for PubMedID 34034599

View details for DOI 10.1073/pnas.2104740118

View details for PubMedID 33850053

Abstract

Pericytes regulate the development of organ-specific characteristics of the brain vasculature such as the blood-brain barrier (BBB) and astrocytic end-feet. Whether pericytes are involved in the control of leukocyte trafficking in the adult central nervous system (CNS), a process tightly regulated by CNS vasculature, remains elusive. Using adult pericyte-deficient mice (Pdgfb ret/ret ), we show that pericytes limit leukocyte infiltration into the CNS during homeostasis and autoimmune neuroinflammation. The permissiveness of the vasculature toward leukocyte trafficking in Pdgfb ret/ret mice inversely correlates with vessel pericyte coverage. Upon induction of experimental autoimmune encephalomyelitis (EAE), pericyte-deficient mice die of severe atypical EAE, which can be reversed with fingolimod, indicating that the mortality is due to the massive influx of immune cells into the brain. Additionally, administration of anti-VCAM-1 and anti-ICAM-1 antibodies reduces leukocyte infiltration and diminishes the severity of atypical EAE symptoms of Pdgfb ret/ret mice, indicating that the proinflammatory endothelium due to absence of pericytes facilitates exaggerated neuroinflammation. Furthermore, we show that the presence of myelin peptide-specific peripheral T cells in Pdgfb ret/ret ;2D2 tg mice leads to the development of spontaneous neurological symptoms paralleled by the massive influx of leukocytes into the brain. These findings indicate that intrinsic changes within brain vasculature can promote the development of a neuroinflammatory disorder.

View details for DOI 10.1073/pnas.2016587118

View details for PubMedID 33653955