Multiple sclerosis

From Proteopedia
Jump to navigation Jump to search

Please have patience as I edit this page over the next week! Thank you!--Kirsten Eldredge 04:06, 21 April 2012 (IDT)

Multiple sclerosis (MS) - an autoimmune disease that effects every patient differently based on the neurologic lesions found throughout the body. While some can go through their lives with relatively mild symptoms and short periods of relapse, others can become incapacitated within years or even months. Defined by Nylander and Hafler, MS is a "multifocal demyelinating disease with progressive neurodegeneration caused by an autoimmune response to self-antigens in a genetically susceptible individual."[1] Inflammation is the primary cause of damage in MS, and though the effects of the disease are well known, and various treatments exist for the disease, the exact identity of an antigen or infectious agent that causes the initiation of a myriad of symptoms is unknown.[2]

There are three ways in which MS is categorized: relapsing-remitting (RRMS), secondary progressive (SPMS), and primary progressive (PPMS). In RRMS, the patient experiences periods of time in which the symptoms increase considerably, although the neurological function of the patient usually returns to normal after the episode. Those with SPMS have symptoms like RRMS, but do not return to normal neurological function after the episode, rather they sustain the neurological damage (such as permanently losing the use of an arm). In PPMS, the patient has an initial episode that never ends. That is, once the symptoms begin, there is no remission in the neurological degradation. A constant autoimmune attack on the patient's body causes increasingly severe symptoms, which can sometimes lead to death.

Taking a biochemical look at the immunopathology and some of the various treatments that exist for MS helps in the understanding that MS is no longer a diagnosis which is hopeless, but is in fact full of hopeful and helpful treatments.

Immunopathology

Classical MS pathology has been characterized by white matter plaques which are typically located in the subcortical or periventricular white matter, optic nerve sheaths, brain stem, and spinal cord. The lesions that occur in these regions are generally identified by perivascular infiltrates that contain clonally expanded (two ectodomains shown, 3qzw), as well as a smaller amount of (3t0e), (2ra4), and rare (4e96) and (2wq9). Pathologists disagree on whether there are different mechanisms for the inflammatory and degenerative components of MS, especially given that older patients have generally progressed further along with their degeneration. There are many proposed degeneration mechanisms including Wallerian degeneration secondary to demyelination, and axonal transection, damage from reactive oxygen species and nitric oxide, or energy failure from mitochondrial dysfunction.[1][3][4][5] Many antigens have been investigated to determine whether they are the cause of T cell problems including: (MBP, 1bx2) with a peptide shown; (PLP, 2xpg) with peptide shown; (MOG, 3csp); oligodendroglia-specific enzyme transaldolase, and heat shock protein alphabeta-crystallin.[1]


Interferon-β

Interferon-β is a protein growth factor that stimulates an antiviral defense. Its encoding gene is one of only two known vertebrate structural genes that lacks introns.[6]

Interferon-β is a relatively simple biological response modifier, with several . It consists of five , as well as multiple interconnecting . Helices A, B and D run , and helices C and E run to the other three helices, but to one another. Helix A consists of residues 6-23; Helix B consists of residues 49-65; Helix C consists of residues 77-91; Helix D consists of residues 112-131; and Helix E consists of residues 135-155.[7][8]

Interferons alpha and beta interact with a receptor at the surface of [9]

Interferon receptor

[10]

Interferon receptor bound to interferon alpha

A comparison of Interferon Alpha to Interferon Beta

Interferon Alpha

Drag the structure with the mouse to rotate

Interferon Beta

Drag the structure with the mouse to rotate

Other Treatments

Interesting discoveries have been made on possible inhibitors of myelin repair functions within the body, with an obvious application to MS treatment. This The structure of the is a module implicated in central nervous system repair inhibition.[11]

Copaxone

Click on the green links to the left to see key structural features of Interferon Beta (PDB entry 1ifa)

Drag the structure with the mouse to rotate

ReferencesReferences

  1. 1.0 1.1 1.2 Nylander A, Hafler DA. Multiple sclerosis. J Clin Invest. 2012 Apr 2;122(4):1180-8. doi: 10.1172/JCI58649. Epub 2012 Apr 2. PMID:22466660 doi:10.1172/JCI58649
  2. Loma I, Heyman R. Multiple sclerosis: pathogenesis and treatment. Curr Neuropharmacol. 2011 Sep;9(3):409-16. PMID:22379455 doi:10.2174/157015911796557911
  3. Dziedzic T, Metz I, Dallenga T, Konig FB, Muller S, Stadelmann C, Bruck W. Wallerian degeneration: a major component of early axonal pathology in multiple sclerosis. Brain Pathol. 2010 Sep;20(5):976-85. Epub 2010 Apr 14. PMID:20477831 doi:10.1111/j.1750-3639.2010.00401.x
  4. Smith KJ, Lassmann H. The role of nitric oxide in multiple sclerosis. Lancet Neurol. 2002 Aug;1(4):232-41. PMID:12849456
  5. Campbell GR, Ziabreva I, Reeve AK, Krishnan KJ, Reynolds R, Howell O, Lassmann H, Turnbull DM, Mahad DJ. Mitochondrial DNA deletions and neurodegeneration in multiple sclerosis. Ann Neurol. 2011 Mar;69(3):481-92. doi: 10.1002/ana.22109. Epub 2010 Nov 8. PMID:21446022 doi:10.1002/ana.22109
  6. Voet, D., Voet, J.G., and C. Pratt. Fundamentals of Biochemistry 3rd Edition. Hoboken, NJ: John Wiley and Sons, 2008. Print.
  7. Kudo M. Management of hepatocellular carcinoma: from prevention to molecular targeted therapy. Oncology. 2010 Jul;78 Suppl 1:1-6. Epub 2010 Jul 8. PMID:20616576 doi:10.1159/000315222
  8. http://www.uniprot.org/uniprot/P00784
  9. [1] Samuel, C.E. "Interferons, Interferon Receptors, Signal Transducer and Transcriptional Activators, and Inteferon Regulatory Factors." J Biol Chem 2007 282: 20045-20046. First Published on May 14, 2007, doi:10.1074/jbc.R700025200
  10. Chill JH, Quadt SR, Levy R, Schreiber G, Anglister J. The human type I interferon receptor: NMR structure reveals the molecular basis of ligand binding. Structure. 2003 Jul;11(7):791-802. PMID:12842042
  11. Mosyak L, Wood A, Dwyer B, Buddha M, Johnson M, Aulabaugh A, Zhong X, Presman E, Benard S, Kelleher K, Wilhelm J, Stahl ML, Kriz R, Gao Y, Cao Z, Ling HP, Pangalos MN, Walsh FS, Somers WS. The structure of the Lingo-1 ectodomain, a module implicated in central nervous system repair inhibition. J Biol Chem. 2006 Nov 24;281(47):36378-90. Epub 2006 Sep 27. PMID:17005555 doi:M607314200

Relevant 3D StructuresRelevant 3D Structures

Interferon BetaInterferon Beta

1au1 - Homo sapiens

1ifa, 1wu3 - Mus musculus

Interferon ReceptorsInterferon Receptors

3s98, 3se3, 3se4, 1n6u, 1n6v, 2hym, 2kz1, 2lag, 3s8w, 3s9d - Homo sapiens

Proteopedia Page Contributors and Editors (what is this?)Proteopedia Page Contributors and Editors (what is this?)

Kirsten Eldredge