Regulation of Mesangial Cell Alpha-Smooth Muscle Actin Expression in 3-Dimensional Matrix by High Glucose and Growth Factors
We postulated that alpha-smooth muscle actin expressed in primary cultured mesangial cells is down-regulated in 3-dimensional (D) culture and up-regulated by high glucose and growth factors.
Primary rat mesangial cells were growth-arrested in 5.6 mM (NG) or 30 mM (HG) glucose for 14 days in 3-D Matrigel. Alpha-SM actin expression was analyzed by immunoblotting, real-time PCR and by alpha-SM actin promoter activity in response to 24 h stimulation with endothelin-1 (ET-1), angiotensin II (Ang II) or HG.
Alpha-SM actin mRNA, protein and promoter activity were reduced to significantly lower levels in 3-D cells compared to cells in 2-D. Up-regulation of alpha-SM expression was stimulated by ET-1, Ang II and HG. Specific inhibitors of protein kinase C (PKC)-alpha, -beta or -zeta prevented alpha-SM upregulation in HG. In NG, PKC and ERK1/2 activation were required for alpha-SM actin accumulation in 3-D in response to ET-1 or Ang II. In HG, enhanced expression of alpha-SM actin in response to ET-1 or Ang II was unchanged during PKC or ERK1/2 inhibition.
Mesangial cells in 3-D express low levels of alpha-SM actin representing a more differentiated state. Regulation of alpha-SM actin expression is dependent on specific PKC isozyme and ERK1/2 signaling.
Figures in this publication
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.