Measuring changes in matrix stiffness using a force conditioning model

Details

• Personal Author:
  Hindman B
• Description:
  The role of a stiffening extra-cellular matrix (ECM) in the development of organ fibrosis and a range of other illness, including cancer and autoimmune/inflammatory diseases, can be difficult to study and interpret. Measuring changes in matrix stiffness can be complicated, involving complex mathematical models and physically complex methodology. Current methods for measuring matrix stiffness involve exposing a sample to a physical strain such as stretching or indentation. However, very few directly measure matrix stiffness while allowing for a global and dynamic response to strain. Here we developed a conditioning stretch protocol to measure the stiffness of collagen matrices and how these biophysical changes are regulated by cellular and matrix cues. Using this assay, we determined the stiffness of matrices arranged by MDA-MB-231 cells, with or without nonmuscle myosin II isoforms, major regulators of actin contractility in nonmuscle cells. We found that inclusion of MDA-MB-231 cells remarkably enhanced the stiffness of the collagen matrix, increasing the elastic modulus from 0.40 Pascals (Pa) to 9.22 Pa. Myosin IIA and IIB were shown to have separate functions in matrix remodeling by MDA-MB-231 cells, as cells lacking these isoforms generated matrices with significantly different elastic moduli (3.42 and 7.20 for IIA and IIB KD cells, respectively). Specific cell and matrix contributions to the overall sample elastic modulus were calculated. These results reveal that Myosin IIA and IIB play distinct and non-redundant roles in matrix remodeling by breast cancer cells. Thus, this stretch conditioning model allows both the direct measurement of ECM stiffness and molecular analysis of impacts of specific cellular components and signaling molecules on ECM remodeling in a controlled environment. We expect this force conditioning protocol to be applicable to the study of diverse diseases involving changes in matrix stiffness. [Description provided by NIOSH]
• Subjects:
  Environmental Exposure Fibrosis Neoplasms Occupational Health Safety
• Keywords:
  Autoimmune Diseases Cancer Cell Function Cellular Effects Cellular Function Elastic Properties Exposure Levels Mathematical Models Organs Physical Stress
• Publisher:
  Keystone Symposia
• Document Type:
  Text
• Genre:
  Abstract or Summary
• Place as Subject:
  OSHA Region 3 ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  HELD - Health Effects Laboratory Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  48
• NIOSHTIC Number:
  nn:20048454
• Citation:
  Fibrosis: from basic mechanisms to targeted therapies joint with the meeting on stromal cells in immunity, Feb 7-11, 2016, Keystone, Colorado. Silverthorne, CO: Keystone Symposia, 2016 Feb; :48
• Federal Fiscal Year:
  2016
• Peer Reviewed:
  False
• Source Full Name:
  Fibrosis: from basic mechanisms to targeted therapies joint with the meeting on stromal cells in immunity, Feb 7-11, 2016, Keystone, Colorado
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:9d7d321996dbfff5108e638620570df5dd20633dfa3ccec48d6e3991a90c16b3373ffe83aa3b2943191a1a5ebb80a58992c0aa94825d5209c874ba44b2c6de51
• Download URL:
  https://stacks.cdc.gov/view/cdc/203205/cdc_203205_DS1.pdf
• File Type:
  [PDF - 271.74 KB ]