| First Author | Zhang G | Year | 2011 |
| Journal | Lab Invest | Volume | 91 |
| Issue | 1 | Pages | 106-23 |
| PubMed ID | 20661225 | Mgi Jnum | J:167191 |
| Mgi Id | MGI:4867384 | Doi | 10.1038/labinvest.2010.135 |
| Citation | Zhang G, et al. (2011) Nicotinic acetylcholine receptor alpha1 promotes calpain-1 activation and macrophage inflammation in hypercholesterolemic nephropathy. Lab Invest 91(1):106-23 |
| abstractText | The nicotinic acetylcholine receptor alpha1 (nAChRalpha1) was investigated as a potential proinflammatory molecule in the kidney, given a recent report that it is an alternative urokinase plasminogen activator (uPA) receptor, in addition to the classical receptor uPAR. Two animal models and in vitro monocyte studies were involved: (1) In an ApoE(-/-) mouse model of chronic kidney disease, glomerular-resident cells and monocytes/macrophages were identified as the primary cell types that express nAChRalpha1 during hypercholesterolemia/uninephrectomy-induced nephropathy. Silencing of the nAChRalpha1 gene for 4 months (6 months on Western diet) prevented the increases in renal monocyte chemoattractant protein-1 and osteopontin expression levels and F4/80+ macrophage infiltration compared with the nonsilenced mice. These changes were associated with significantly reduced transforming growth factor-beta1 mRNA (50% decrease) and alpha smooth muscle actin-positive (alphaSMA+) myofibroblasts (90% decrease), better glomerular and tubular basement membranes (GBM/TBM) preservation (threefold less disintegration), and better renal function preservation (serum creatinine 40% lower) in the nAChRalpha1-silenced mice. The nAChRalpha1 silencing was also associated with significantly reduced renal tissue calcium deposition (78% decrease) and calpain-1 (but not calpain-2) activation (70% decrease). (2) The nAChRalpha1 was expressed in vitro by mouse monocyte cell line WEHI-274.1. The silencing of nAChRalpha1 significantly reduced both calpain-1 and -2 activities, and reduced the degradation of the calpain substrate talin. (3) To further explore the role of calpain-1 activity in hypercholesterolemic nephropathy, disease severities were compared in CAST(-/-)ApoE(-/-) (calpain overactive) mice and ApoE(-/-) mice fed with Western diet for 10 months (n=12). Macrophages were the main cell type of renal calpain-1 production in the model. The number of renal F4/80+ macrophages was 10-fold higher in the CAST(-/-)ApoE(-/-) mice (P<0.05), and was associated with a significantly higher level of alphaSMA+ cells, increased GBM/TBM destruction, and higher serum creatinine levels. Our studies suggest that the receptor nAChRalpha1 is an important regulator of calpain-1 activation and inflammation in the chronic hypercholesterolemic nephropathy. This new proinflammatory pathway may also be relevant to other disorders beyond hyperlipidemic nephropathy. |
