title: Utility of survival motor neuron ELISA for spinal muscular atrophy clinical and preclinical analyses.
abstract: OBJECTIVE
  Genetic defects leading to the reduction of the survival motor neuron protein (SMN) are a causal factor for Spinal Muscular Atrophy (SMA). While there are a number of therapies under evaluation as potential treatments for SMA, there is a critical lack of a biomarker method for assessing efficacy of therapeutic interventions, particularly those targeting upregulation of SMN protein levels. Towards this end we have engaged in developing an immunoassay capable of accurately measuring SMN protein levels in blood, specifically in peripheral blood mononuclear cells (PBMCs), as a tool for validating SMN protein as a biomarker in SMA.
  
  
  METHODS
  A sandwich enzyme-linked immunosorbent assay (ELISA) was developed and validated for measuring SMN protein in human PBMCs and other cell lysates. Protocols for detection and extraction of SMN from transgenic SMA mouse tissues were also developed.
  
  
  RESULTS
  The assay sensitivity for human SMN is 50 pg/mL. Initial analysis reveals that PBMCs yield enough SMN to analyze from blood volumes of less than 1 mL, and SMA Type I patients' PBMCs show ∼90% reduction of SMN protein compared to normal adults. The ELISA can reliably quantify SMN protein in human and mouse PBMCs and muscle, as well as brain, and spinal cord from a mouse model of severe SMA.
  
  
  CONCLUSIONS
  This SMN ELISA assay enables the reliable, quantitative and rapid measurement of SMN in healthy human and SMA patient PBMCs, muscle and fibroblasts. SMN was also detected in several tissues in a mouse model of SMA, as well as in wildtype mouse tissues. This SMN ELISA has general translational applicability to both preclinical and clinical research efforts.
authors: Spinal Muscular Atrophy Foundation, New York, New York, United States of America. dkobayashi@smafoundation.org
authors: Dione T
authors: DT
authors: Kobayashi
authors: Rory J
authors: RJ
authors: Olson
authors: Laurel
authors: L
authors: Sly
authors: Chad J
authors: CJ
authors: Swanson
authors: Brett
authors: B
authors: Chung
authors: Nikolai
authors: N
authors: Naryshkin
authors: Jana
authors: J
authors: Narasimhan
authors: Anuradha
authors: A
authors: Bhattacharyya
authors: Michael
authors: M
authors: Mullenix
authors: Karen S
authors: KS
authors: Chen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D002478:Cells, Cultured; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D009134:Muscular Atrophy, Spinal / Q000378:metabolism*; D015203:Reproducibility of Results; D055532:SMN Complex Proteins / Q000032:analysis* / Q000378:metabolism
chemical_list: D055532:SMN Complex Proteins