Dataset Information

A monoclonal anti-HMGB1 antibody attenuates neurodegeneration in an experimental animal model of glaucoma

ABSTRACT: Neuroinflammation is a crucial process for the loss of retinal ganglion cells (RGC), a major characteristic of glaucoma. High expression of high mobility group box protein 1 (HMGB1) plays a detrimental role in inflammatory processes and is elevated in the retinas of glaucoma patients. Therefore, this study aimed to investigate the effects of intravitreal injection of an anti-HMGB1 monoclonal antibody (anti-HMGB1 Ab) in an experimental animal model of glaucoma. Two groups of Spraque Dawley rats received episcleral vein occlusion to chronically elevate intraocular pressure (IOP): (1) IgG group, intravitreal injection of an unspecific IgG as a control, n=5, (2) HMGB1 group, intravitreal injection of an anti-HMGB1 Ab, n=6. IOP, retinal nerve fiber layer thickness (RNFLT), and the retinal flash response was monitored longitudinally. Post-mortem examinations included immunohistochemistry, microarray, and mass spectrometric analysis. RNFLT was significantly increased in the HMGB1 group compared to the IgG group (p<0.001). RGC density showed improved neuronal cell survival in the retina in HMGB1 compared to the IgG group (p<0.01). Mass spectrometric proteomic analysis of retinal tissue showed increased abundance of RNA metabolism-associated heterogeneous nuclear ribonucleoproteins (hnRNPs), such as hnRNP U, D, and H2, in animals injected with the anti-HMGB1 Ab, indicating that application of the antibody may cause increased gene expression. Microarray analysis showed significantly decreased expression of C-X-C motif chemokine ligand 8 (CXCL8, p<0.05) and connective tissue growth factor (CTGF, p<0.01) in the HMGB1 group. Thus, these data suggest that intravitreal injection of anti-HMGB1 Ab reduced HMGB1-dependent inflammatory signaling and mediated RGC neuroprotection.

INSTRUMENT(S): LTQ Orbitrap XL

ORGANISM(S): Rattus Norvegicus (rat)

TISSUE(S): Retina

DISEASE(S): Primary Open Angle Glaucoma

SUBMITTER: Henrik Tonner

LAB HEAD: Prof. Dr. Dr. Franz H. Grus

PROVIDER: PXD031987 | Pride | 2022-05-20

REPOSITORIES: Pride

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Publications

A Monoclonal Anti-HMGB1 Antibody Attenuates Neurodegeneration in an Experimental Animal Model of Glaucoma.

Tonner Henrik H Hunn Selina S Auler Nadine N Schmelter Carsten C Beutgen Vanessa M VM von Pein Harald D HD Pfeiffer Norbert N Grus Franz H FH

International journal of molecular sciences 20220407 8

Neuroinflammation is a crucial process for the loss of retinal ganglion cells (RGC), a major characteristic of glaucoma. High expression of high-mobility group box protein 1 (HMGB1) plays a detrimental role in inflammatory processes and is elevated in the retinas of glaucoma patients. Therefore, this study aimed to investigate the effects of the intravitreal injection of an anti-HMGB1 monoclonal antibody (anti-HMGB1 Ab) in an experimental animal model of glaucoma. Two groups of Spraque Dawley ra ...[more]

PMID: 35456925

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Project description:Glaucoma is a group of optic neuropathies characterized by the progressive degeneration of retinal ganglion cells (RGCs) as well as their axons leading to irreversible loss of sight. Medical management of the intraocular pressure (IOP) still represents the gold standard in glaucoma therapy, which only manages a risk factor and does not directly address the neurodegenerative component of this eye disease. Recently, our group showed that antibody derived immunopeptides (encoding complementarity-determining regions, CDRs) provide attractive glaucoma medication candidates and directly interfere its pathogenic mechanisms by different modes of action. In accordance with these findings, the present study showed the synthetic CDR2 peptide (INSDGSSTSYADSVK) significantly increased the RGCs viability in vitro in a concentration-dependent manner (p < 0.05 using a CDR2 concentration of 50 µg/mL). Employing state-of the-art immunoprecipitation experiments, we confirmed that synthetic CDR2 exhibited a high affinity towards the retinal target protein histone H3.1 (HIST1H3A) (p < 0.001 and log2 fold change > 3). Furthermore, virtual docking analyses predicted potential CDR2-specific binding regions of HIST1H3A, which might represent essential PTM sites for epigenetic regulations. Quantitative MS analysis revealed that 39 proteins were significantly changed between CDR2-treated and untreated control retinae (p < 0.05). An up-regulation of proteins involved in the energy production (e.g., ATP5F1B and MT-CO2) as well as the regulatory ubiquitin proteasome system (e.g., PSMC5) was induced by the synthetic CDR2 peptide. On the other hand, metabolic key enzymes (e.g., DDAH1 and MAOB) as well as ER stress-related proteins (e.g., SEC22B and VCP) were found with low abundancy in CDR2-treated retinae and were also partially confirmed by microarray technology. Based on these findings, it can be hypothesized that the specific protein-peptide interaction influences the regulatory epigenetic function of HIST1H3A promoting the neuroprotective mechanism on RGCs in vitro. It also might serve as basis for a synergistic immunotherapy of glaucoma in the future.

Project description:Glaucoma is a complex, multifactorial optic neuropathy mainly characterized by the progressive loss of retinal ganglion cells (RGCs) and their axons, resulting in a decline of visual function. The pathogenic molecular mechanism of glaucoma is still not well understood, and therapeutic strategies specifically addressing the neurodegenerative component of this ocular disease are urgently needed. Novel immunotherapeutics might overcome this problem by targeting specific molecular structures in the retina and providing direct neuroprotection via different modes of action. Within the scope of this research, the present study showed for the first time beneficial effects of the synthetic CDR1 peptide SCTGTSSDVGGYNYVSWYQ on the viability of RGCs ex vivo in a concentration-dependent manner compared to untreated control explants (CTRL, 50 µg/mL: p < 0.05 and 100 µg/mL: p < 0.001). Thereby, this specific peptide was identified first as a potential biomarker candidate in the serum of glaucoma patients and was significantly lower expressed in systemic IgG molecules compared to healthy control subjects. Furthermore, MS-based co-immunoprecipitation experiments confirmed the specific interaction of synthetic CDR1 with retinal acidic leucine-rich nuclear phosphoprotein 32A (ANP32A; p < 0.001 and log2 fold change > 3), which is a highly expressed protein in neurological tissues with multifactorial biological functions. In silico binding prediction analysis revealed the N-terminal leucine-rich repeat (LRR) domain of ANP32A as a significant binding site for synthetic CDR1, which was previously reported as an important docking site for protein-protein interactions (PPI). In accordance with these findings, quantitative proteomic analysis of the retinae ± CDR1 treatment resulted in the identification of 25 protein markers, which were significantly differentially distributed between both experimental groups (CTRL and CDR1, p < 0.05). Particularly, acetyl-CoA biosynthesis I-related enzymes (e.g., DLAT and PDHA1), as well as cytoskeleton-regulating proteins (e.g., MSN), were highly expressed by synthetic CDR1 treatment in the retina; on the contrary, direct ANP32A-interacting proteins (e.g., NME1 and PPP2R4), as well as neurodegenerative-related markers (e.g., CEND1), were identified with significant lower abundancy in the CDR1-treated retinae compared to CTRL. Furthermore, retinal protein phosphorylation and histone acetylation were also affected by synthetic CDR1, which are both partially controlled by ANP32A. In conclusion, the synthetic CDR1 peptide provides a great translational potential for the treatment of glaucoma in the future by eliciting its neuroprotective mechanism via specific interaction with ANP32A’s N terminal LRR domain.

Project description:Human CD34+ stem cells are mobilized from bone marrow to sites of tissue ischemia and play an important role in tissue revascularization. This study used a murine model to test the hypothesis that intravitreal injection of human CD34+ stem cells harvested from bone marrow (BMSCs) can have protective effects in eyes with diabetic retinopathy. Streptozotocin-induced diabetic mice (C57BL/6J) were used as a model for diabetic retinopathy. Subcutaneous implantation of Alzet pump, loaded with Tacrolimus and Rapamycin, 5 days prior to intravitreal injection provided continuous systemic immunosuppression for the study duration to avoid rejection of human cells. Human CD34+ BMSCs were harvested from the mononuclear cell fraction of bone marrow from a healthy donor using magnetic beads. The CD34+ cells were labeled with enhanced green fluorescent protein (EGFP) using a lentiviral vector. The right eye of each mouse received an intravitreal injection of 50,000 EGFP-labeled CD34+ BMSCs or phosphate buffered saline (PBS). Simultaneous multimodal in vivo retinal imaging system consisting of fluorescent scanning laser ophthalmoscopy (enabling fluorescein angiography), optical coherence tomography (OCT) and OCT angiography was used to confirm the development of diabetic retinopathy and study the in vivo migration of the EGFP-labeled CD34+ BMSCs in the vitreous and retina following intravitreal injection. After imaging, the mice were euthanized, and the eyes were removed for immunohistochemistry. In addition, microarray analysis of the retina and retinal flat mount analysis of retinal vasculature were performed. The development of retinal microvascular changes consistent with diabetic retinopathy was visualized using fluorescein angiography and OCT angiography between 5 and 6 months after induction of diabetes in all diabetic mice. These retinal microvascular changes include areas of capillary nonperfusion and late leakage of fluorescein dye. Multimodal in vivo imaging and immunohistochemistry identified EGFP-labeled cells in the superficial retina and along retinal vasculature at 1 and 4 weeks following intravitreal cell injection. Microarray analysis showed changes in expression of 162 murine retinal genes following intravitreal CD34+ BMSC injection when compared to PBS-injected control. The major molecular pathways affected by intravitreal CD34+ BMSC injection in the murine retina included pathways implicated in the pathogenesis of diabetic retinopathy including Toll-like receptor, MAP kinase, oxidative stress, cellular development, assembly and organization pathways. At 4 weeks following intravitreal injection, retinal flat mount analysis showed preservation of the retinal vasculature in eyes injected with CD34+ BMSCs when compared to PBS-injected control. The study findings support the hypothesis that intravitreal injection of human CD34+ BMSCs results in retinal homing and integration of these human cells with preservation of the retinal vasculature in murine eyes with diabetic retinopathy.

Project description:Purpose: Next-generation sequencing (NGS) has revolutionized systems-based analysis of cellular pathways. The goals of this study are using transcriptome profiling (RNA-seq) to evaluate the effects of anti-S100a9 antibody on the global transcriptome of the colon tissues of the AOM/DSS mouse model (a model that mimics the human colitis-associated colon cancer development). Methods: 36 five-week-old male ICR mice were randomized divided into three groups: control (i.e. no AOM/DSS and antibody treatment), AOM/DSS+IgG Ab (1.5 mg/kg), and AOM/DSS+anti-S100a9 Ab (1.5 mg/kg). Mice were intraperitoneal injected with a single dose of 10 mg/kg azoxymethane (AOM) (A5486; Sigma) on day 1. One week after the AOM injection, mice were given three cycles of DSS (cycle 1: 2%, 7 days; cycle 2: 1.5%, 5 days; and cycle 3: 1.5%, 5 days, DSS: 36–50 kDa; MP Biomedicals, CA, USA) in their drinking water, and then distilled water until the end of the experiment. Antibodies were administrated intravenously every two days during the three cycles of DSS treatment. Mice were sequentially killed randomly at the end of the 18th week, and at least five mice were killed for each group at each time point. RNAs were extracted by Trizol and sequenced by Solexa high-throughput sequencing service (Oebiotech, Shanghai, China). Data were extracted and normalized according to the manufacturer’s standard protocol.Each group has three mices' colon tissues be tested. Results: Log-fold changes of up- or down-regulated mRNAs between the control and experiment group were selected with a significance threshold of p<0.05. There are 1017 mRNAs were up-regulated and 815 were down-regulated in “AOM/DSS+IgG Ab" group comparing to “control" group. There are 385 mRNAs were up-regulated and 163 were down-regulated in “AOM/DSS+anti-S100a9 Ab" group comparing to “control" group. There are 1314 mRNAs were up-regulated and 968 were down-regulated in “AOM/DSS+anti-S100a9 Ab" group comparing to “AOM/DSS+IgG Ab". Conclusions: Our study describes the global transciptome changes of colon tissues of the AOM/DSS mouse model induced by anti-S100a9 antibody treatment.

Dataset Information

A monoclonal anti-HMGB1 antibody attenuates neurodegeneration in an experimental animal model of glaucoma

Publications

A Monoclonal Anti-HMGB1 Antibody Attenuates Neurodegeneration in an Experimental Animal Model of Glaucoma.

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