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Type 2 Diabetic Coronary Vascular Smooth Muscle Cells Exhibit Decreased Stiffness and Decreased Adhesion
Author(s) -
McCallinhart Patricia,
Sun Zhe,
Meininger Gerald A.,
Trask Aaron J.
Publication year - 2018
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2018.32.1_supplement.899.4
Subject(s) - extracellular matrix , vascular smooth muscle , stiffness , arterial stiffness , decellularization , fibronectin , elastic modulus , medicine , artery , biomedical engineering , materials science , chemistry , cardiology , anatomy , smooth muscle , composite material , blood pressure , biochemistry
We previously reported that type 2 diabetic (T2D) coronary resistance microvessels (CRMs) undergo early inward hypertrophic remodeling with reduced vessel stiffness that is associated with a proliferative VSMC phenotype. We also previously revealed that there is no difference in stiffness of decellularized CRMs from diabetic (db/db) and normal (Db/db) mice, suggesting that the decreased stiffness of the intact diabetic CRM is not due to alterations in the extracellular matrix (ECM) of those microvessels. Given that diabetic CRMs are less stiff and this decreased stiffness does not appear to be due differences in the mechanical strength of the surrounding ECM, the aim of the current study was to determine whether a reduction in cellular mechanical stiffness between Db/db and db/db CRM vascular smooth muscle cells (VSMCs) may be responsible. VSMCs were isolated from 16 week old Db/db and db/db mice and passage 1 cells were used for all experiments (n=6–7 for all groups). Using an atomic force microscope with probes coated with fibronectin (FN), a nano‐indentation protocol was used to measure cellular stiffness and adhesion to FN. Elastic modulus, a measurement of cellular stiffness, was reduced in diabetic coronary VSMCs compared to normal (Db/db: 6.74 ± 0.40 kPa vs. db/db: 4.96 ± 0.35 kPa, p = 0.004). By comparison, there were no significant differences in elastic modulus between normal and diabetic aortic VMSCs (Db/db: 5.39 ± 0.79 kPa vs. db/db: 5.18 ± 0.87 kPa, p = 0.861). Additionally, diabetic coronary VSMCs had reduced adhesive force to fibronectin compared to normal coronary VSMCs (Db/db: 54.78 ± 5.49 vs. db/db: 39.8 ± 3.43 pN, p = 0.03). In a separate experiment, qPCR was performed on mRNA from normal and diabetic CRM VSMCs. Alpha‐smooth muscle actin trended lower in db/db CRM VSMCs ( p =0.07), indicating a de‐differentiated phenotype. Cell cycle regulator, p53, had significantly reduced mRNA expression in the diabetic coronary VSMCs over control VSMCs (Db/db 1.00±0.06 vs. db/db 0.63±0.08, p<0.01). These data show that reductions in cellular stiffness and adhesion to the ECM of diabetic CRM VSMCs may underlie ex vivo whole microvessel mechanical properties to account for reduced CRM stiffness. The changes in diabetic coronary VSMC stiffness and adhesion may be the result of VMSC phenotypic switching to a more de‐differentiated/proliferative phenotype. Support or Funding Information Support: NIH R00 HL116769 and S10 OD023438 and Nationwide Children's Hospital to AJT This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .