Dataset Information

Gene Expression Profiles of Lymphocytes Obtained from Mice treated with Glatimer Acetate and ither Glatiramatoids

ABSTRACT: Glatiramer acetate (GA; Copaxone), is a complex mixture of synthetic polypeptides approved for treatment of multiple sclerosis (MS). GA is an altered peptide ligand (APL) of myelin basic protein (MBP), an encephalitic autoantigen implicated in MS. GA induces GA-reactive T cells, which upregulate expression of anti-inflammatory and neurotrophic substances in the CNS. The antigenic sequences in glatiramoids cannot be completely characterized; nevertheless, differences among them can cause toxicity. We conducted microarray analyses to determine whether gene expression by GA-reactive lymphocytes from mouse spleens could differentiate GA from other glatiramoids. Expression of 135 genes was unique to cells reactivated by GA vs by intentionally altered GA and other glatiramoids. Significantly (p<0.01) altered expression of 207 genes was observed by cells reactivated by GA vs purported generic GA. Some APLs of MBP have caused serious adverse effects in MS patients. The influence of altered gene expression on glatiramoid safety warrants further investigation.

ORGANISM(S): Mus musculus

PROVIDER: GSE40566 | GEO | 2013/08/01

SECONDARY ACCESSION(S): PRJNA174403

REPOSITORIES: GEO

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Project description:Glatiramer acetate (GA; Copaxone), is a complex mixture of synthetic polypeptides approved for treatment of multiple sclerosis (MS). GA is an altered peptide ligand (APL) of myelin basic protein (MBP), an encephalitic autoantigen implicated in MS. GA induces GA-reactive T cells, which upregulate expression of anti-inflammatory and neurotrophic substances in the CNS. The antigenic sequences in glatiramoids cannot be completely characterized; nevertheless, differences among them can cause toxicity. We conducted microarray analyses to determine whether gene expression by GA-reactive lymphocytes from mouse spleens could differentiate GA from other glatiramoids. Expression of 135 genes was unique to cells reactivated by GA vs by intentionally altered GA and other glatiramoids. Significantly (p<0.01) altered expression of 207 genes was observed by cells reactivated by GA vs purported generic GA. Some APLs of MBP have caused serious adverse effects in MS patients. The influence of altered gene expression on glatiramoid safety warrants further investigation. Glatiramoid samples for SPL cell activation were grouped into four categories: 1) Verified GA, which included GA-RS (22 samples) and GA drug product (GA-DP, 34 samples from 30 batches) manufactured by Teva; 2) Deliberately Modified GA (DM-GA; 9 samples), which included glatiramoids made by Teva that were similar to GA but modified in a variety of ways: prepared with different ingredients (e.g., missing a constituent amino acid); prepared with the same amino acids in the same molar ratio as GA, but with defined amino acid sequences and different molecular weights (referred to as peptide markers TV-35 and TV-66); synthesized by a different process (e.g., changing acetolytic cleavage conditions, alternating polymerization initiator); exposed to destabilizing conditions (e.g., degradation by acid, base, and heat); 3) Unverified Glatiramoids, which included 4 samples, TV-5010 and 3 glatiramoids synthesized to be similar to GA but not manufactured using the Teva-patented manufacturing process; and 4) Unverified Generic GA, which included samples from 2 glatiramoids (M-bM-^@M-^\GA-NM-bM-^@M-^] 11 samples from 5 different batches, and 2 M-bM-^@M-^\GA-CM-bM-^@M-^] samples from a single batch) marketed as generic GA manufactured by companies other than Teva .

Project description:For decades, policies regarding generic medicines have sought to provide patients with economical access to safe and effective drugs, while encouraging the development of new therapies. This balance is becoming more challenging for physicians and regulators as biologics and non-biological complex drugs (NBCDs) such as glatiramer acetate demonstrate remarkable efficacy, because generics for these medicines are more difficult to assess. We sought to develop computational methods that use transcriptional profiles to compare branded medicines to generics, robustly characterizing differences in biological impact. We combined multiple computational methods to determine whether differentially expressed genes result from random variation, or point to consistent differences in biological impact of the generic compared to the branded medicine. We applied these methods to analyze gene expression data from mouse splenocytes exposed to either branded glatiramer acetate or a generic. The computational methods identified extensive evidence that branded glatiramer acetate has a more consistent biological impact across batches than the generic, and has a distinct impact on regulatory T cells and myeloid lineage cells. In summary, we developed a computational pipeline that integrates multiple methods to compare two medicines in an innovative way. This pipeline, and the specific findings distinguishing branded glatiramer acetate from a generic, can help physicians and regulators take appropriate steps to ensure safety and efficacy. Glatiramoid samples for SPL cell activation were grouped into four categories: 1) Verified GA, which included GA-RS (22 biological samples) and GA drug product (GA-DP, 34 biological samples from 30 batches) manufactured by Teva; 2) Deliberately Modified GA (DM-GA; 9 biological samples), which included glatiramoids made by Teva that were similar to GA but modified in a variety of ways: prepared with different ingredients (e.g., missing a constituent amino acid); prepared with the same amino acids in the same molar ratio as GA, but with defined amino acid sequences and different molecular weights (referred to as peptide markers TV-35 and TV-66); synthesized by a different process (e.g., changing acetolytic cleavage conditions, alternating polymerization initiator); exposed to destabilizing conditions (e.g., degradation by acid, base, and heat); 3) Unverified Glatiramoids, which included 4 biological samples, TV-5010 and 3 glatiramoids synthesized to be similar to GA but not manufactured using the Teva-patented manufacturing process; and 4) Unverified Generic GA, which included samples from 2 glatiramoids (M-bM-^@M-^\GA-QM-bM-^@M-^] 11 biological samples from 5 different batches, and 2 M-bM-^@M-^\GA-CM-bM-^@M-^] samples from a single batch) marketed as generic GA manufactured by companies other than Teva.

Project description:Astrocytes are instrumental in both maintaining CNS homeostasis and responding to tissue injury. While astrocyte activation may be a beneficial response to acute pathologies, prolonged reactive gliosis is thought to be injurious in neurodegenerative diseases, including multiple sclerosis (MS). A major limitation of studying neurodegenerative diseases is lack of human pathological specimens obtained during the acute stages, thereby relegating research to post mortem specimens often obtained years after the initiation of pathology. Rodent reactive astrocytes have been shown to be cytotoxic to neurons and oligodendrocytes but may differ from human cells, especially in diseases with known genetic susceptibility. Herein, we purified human CD49f+ astrocytes from differentiated induced pluripotent stem cells derived from individual patient and control peripheral white blood cell samples. We compared TNF and IL1a stimulated human reactive astrocytes from 7 persons with MS and 6 non-MS controls and show their specific astrocyte transcriptomic profiles are remarkably similar to those described in rodents. The functional effect of astrocyte conditioned media (ACM) was examined in a human oligodendrocyte precursor cell (OPC) line differentiation assay using a transgenic secreted reporter of myelin basic protein (MBP) expression. ACM was not cytotoxic to the OPCs but robustly inhibited the MBP reporter. No differences were seen between MS and control stimulated astrocytes at either the transcript level or in functional OPC suppression assays. We next used RNAseq to interrogate differentially expressed genes in the OPC lines that had suppressed differentiation from the human ACM. Remarkably, not only was OPC differentiation and myelin gene expression suppressed, but we observed induction of several immune pathways and Nf-κB signaling in OPCs exposed to the ACM. These data support the notion that reactive astrocytes can inhibit OPC differentiation thereby limiting their remyelination capacity, and that OPCs take on an immune profile in the context of inflammatory cues.