SDF‐1α (Stromal Cell‐Derived Factor 1α) Induces Cardiac Fibroblasts, Renal Microvascular Smooth Muscle Cells, and Glomerular Mesangial Cells to Proliferate, Cause Hypertrophy, and Produce Collagen

Figures

• 

  Figure 1. A, Western blots show that cardiac fibroblasts (CFs) from spontaneously hypertensive rats (SHR) and normotensive Wistar–Kyoto rats (WKY) express CXCR4 (C‐X‐C motif chemokine receptor 4) receptors and that the expression of CXCR4 receptors is modestly increased in SHR CFs and modestly decreased in both SHR and WKY CFs by 4 days of treatment with SDF‐1α (stromal cell‐derived factor 1α; 10 nmol/L) plus sitagliptin (1 μmol/L; treated). B, Bar graph summarizes the densitometric analysis of the bands corresponding to the CXCR4 receptor (normalized to β‐actin). Values are means and SEM.

• 

  Figure 2. Western blots show that glomerular mesangial cells (GMCs) and preglomerular vascular smooth muscle cells (PGVSMCs) from spontaneously hypertensive rats (SHR; A) and normotensive Wistar–Kyoto rats (WKY; C) express CXCR4 (C‐X‐C motif chemokine receptor 4) receptors and that the expression of CXCR4 receptors is similar in untreated (control) vs cells treated with SDF‐1α (stromal cell‐derived factor 1α; 10 nmol/L) plus sitagliptin (1 μmol/L) for 4 days (treated). Bar graphs summarize the densitometric analysis of the bands corresponding to the CXCR4 receptor (normalized to β‐actin) for SHR (B) and WKY (D) GMCs and PGVSMCs. Values are means and SEM.

• 

  Figure 3. Bar graphs depict the concentration‐dependent effects of SDF‐1α (stromal cell‐derived factor 1α; 1, 3, and 10 nmol/L) on cell number (A and B), 3H‐leucine incorporation (C and D), and 3H‐proline incorporation (E and F) in cardiac fibroblasts (CFs) from spontaneously hypertensive rats (SHR; A, C, and E) and normotensive Wistar–Kyoto rats (WKY; B, D, and F) in the absence and the presence of sitagliptin (1 μmol/L). Each P value at the top of each main panel is the 3‐way interaction P value from a 3‐factor ANOVA. These P values demonstrate that the strain from which the cells were derived (SHR vs WKY) interacts with sitagliptin to determine the overall effects of SDF‐1α on cell number, 3H‐leucine incorporation, and 3H‐proline incorporation. Each P value at the top of each subpanel is the 2‐way interaction P value from a 2‐factor ANOVA. These P values demonstrate that for all 3 variables and for both SHR and WKY CFs, sitagliptin augmented responses to SDF‐1α. *Significant difference (P<0.05; Fisher least significant difference test) between the indicated concentration of SDF‐1α and the basal values (ie, values in the absence of SDF‐1α) for the indicated variable. †Significant…

• 

  Figure 4. Bar graphs depict the concentration‐dependent effects of SDF‐1α (stromal cell‐derived factor 1α; 1, 3, and 10 nmol/L) on cell number (A and B), 3H‐leucine incorporation (C and D), and 3H‐proline incorporation (E and F) in preglomerular vascular smooth muscle cells (PGVSMCs) from spontaneously hypertensive rats (SHR; A, C, and E) and normotensive Wistar–Kyoto rats (WKY; B, D, and F) in the absence and the presence of sitagliptin (1 μmol/L). Each P value at the top of each main panel is the 3‐way interaction P value from a 3‐factor ANOVA. These P values demonstrate that the strain from which the cells were derived (SHR vs WKY) interacts with sitagliptin to determine the overall effects of SDF‐1α on cell number, 3H‐leucine incorporation, and 3H‐proline incorporation. The significant 2‐way interaction P values in subpanels (A, C, E, and F) demonstrate that sitagliptin augmented responses to SDF‐1α. In WKY PGVSMCs, SDF‐1α and sitagliptin modestly enhanced cell number or 3H‐leucine incorporation, but the interaction was not significant. *Significant difference (P<0.05; Fisher least significant difference test) between the indicated concentration of SDF‐1α and the basal values (ie,…

• 

  Figure 5. Bar graphs depict the concentration‐dependent effects of SDF‐1α (stromal cell‐derived factor 1α; 1, 3, and 10 nmol/L) on cell number (A and B), 3H‐leucine incorporation (C and D), and 3H‐proline incorporation (E and F) in glomerular mesangial cells (GMCs) from spontaneously hypertensive rats (SHR; A, C, and E) and normotensive Wistar–Kyoto rats (WKY; B, D, and F) in the absence and the presence of sitagliptin (1 μmol/L). The P values at the top of the main panels for 3H‐leucine incorporation (C and D) and 3H‐proline incorporation (E and F) are the 3‐way interaction P values from a 3‐factor ANOVA. These P values demonstrate that the strain from which the cells were derived (SHR vs WKY) interacts with sitagliptin to determine the overall effects of SDF‐1α on 3H‐leucine incorporation and 3H‐proline incorporation. For cell number, however, the strain×sitagliptin×SDF‐1α interaction was not significant. The P values at the top of subpanels (A, B, C, E, and F) are the 2‐way interaction P values from a 2‐factor ANOVA. These P values demonstrate that sitagliptin augmented responses to SDF‐1α. In WKY GMCs, SDF‐1α and sitagliptin modestly enhanced 3H‐leucine incorporation, but the…

• 

  Figure 6. Bar graphs summarize changes (y‐axes) induced by SDF‐1α (stromal cell‐derived factor 1α; 10 nmol/L) in cell number (A and B), 3H‐leucine incorporation (C and D), and 3H‐proline incorporation (E and F) in cardiac fibroblasts (CFs) from spontaneously hypertensive rats (SHR; A, C, and E) and normotensive Wistar–Kyoto rats (WKY; B, D, and F) under 4 different conditions: (1) without sitagliptin and without AMD3100 (−/−), (2) without sitagliptin but with AMD3100 (−/+), (3) with sitagliptin but without AMD3100 (+/−), (4) both with sitagliptin and with AMD3100 (+/+). The concentrations of sitagliptin and AMD3100 were 1 and 10 μmol/L, respectively. Each P value at the top of each subpanel panel is the 2‐way interaction P value from a 2‐factor ANOVA. These P values demonstrate that for both SHR and WKY CFs, AMD3100 inhibited the response to SDF‐1α, and more so in cells cotreated with sitagliptin because in the presence of sitagliptin there was more response to inhibit. *Significant difference (P<0.05; Fisher least significant difference test) between −/− vs −/+ or between +/− vs +/+. †Significant difference (P<0.05; Fisher least significant difference test) between −/− vs +/−. Values are…

• 

  Figure 7. Bar graphs summarize changes (y‐axes) induced by SDF‐1α (stromal cell‐derived factor 1α; 10 nmol/L) in cell number (A and B), 3H‐leucine incorporation (C and D), and 3H‐proline incorporation (E and F) in preglomerular vascular smooth muscle cells (PGVSMCs) from spontaneously hypertensive rats (SHR; A, C, and E) and normotensive Wistar–Kyoto rats (WKY; B, D, and F) under 4 different conditions: (1) without sitagliptin and without AMD3100 (−/−), (2) without sitagliptin but with AMD3100 (−/+), (3) with sitagliptin but without AMD3100 (+/−), (4) both with sitagliptin and with AMD3100 (+/+). The concentrations of sitagliptin and AMD3100 were 1 and 10 μmol/L, respectively. The P values at the top of subpanels (A, C, D, E, and F) are the 2‐way interaction P values from a 2‐factor ANOVA. These P values demonstrate that AMD3100 inhibited the response to SDF‐1α, and more so in cells cotreated with sitagliptin because in the presence of sitagliptin there was more response to inhibit. AMD3100 also blocked the effects of SDF‐1α in subpanel B (cell number for WKY PGVSMCs) but, in this case, equally in sitagliptin vs non–sitagliptin‐treated cells. *Significant difference (P<0.05; Fisher least…

• 

  Figure 8. Bar graphs summarize changes (y‐axes) induced by SDF‐1α (stromal cell‐derived factor 1α; 10 nmol/L) in cell number (A and B), 3H‐leucine incorporation (C and D), and 3H‐proline incorporation (E and F) in glomerular mesangial cells (GMCs) from spontaneously hypertensive rats (SHR; A, C, and E) and normotensive Wistar–Kyoto rats (WKY; B, D, and F) under 4 different conditions: (1) without sitagliptin and without AMD3100 (−/−), (2) without sitagliptin but with AMD3100 (−/+), (3) with sitagliptin but without AMD3100 (+/−), (4) both with sitagliptin and with AMD3100 (+/+). The P values at the top of subpanels (A, B, C, E, and F) are the 2‐way interaction P values from a 2‐factor ANOVA. These P values demonstrate that AMD3100 inhibited the response to SDF‐1α, and more so in cells cotreated with sitagliptin because in the presence of sitagliptin there was more response to inhibit. AMD3100 also blocked the effects of SDF‐1α in subpanel D (3H‐leucine incorporation for WKY GMCs) but, in this case, equally in sitagliptin vs non–sitagliptin‐treated cells. *Significant difference (P<0.05; Fisher least significant difference test) between −/− vs −/+ or between +/− vs +/+. †Significant…

• 

  Figure 9. Bar graphs illustrate the effects of SDF‐1α (stromal cell‐derived factor 1α; 10 nmol/L, with added sitagliptin at 1 μmol/L to enhance the response) on cell number in the absence and the presence of pertussis toxin (A; 100 ng/mL), U73122 (B; 10 μmol/L), GF109203X (C; 10 μmol/L), and PD98059 (D; 10 μmol/L) in cardiac fibroblasts (CFs) from spontaneously hypertensive rats (SHR). Each set of P values in each panel are from a 2‐factor ANOVA (factor A, level of SDF‐1α; factor B, level of indicated inhibitor). The interaction P values show that the effects of SDF‐1α were blocked by the indicated inhibitor. *,†,‡,§Significant difference (P<0.05; Fisher least significant difference test) from first, second, third, and fourth columns, respectively. Values are means and SEM.

• 

  Figure 10. Bar graphs illustrate the effects of SDF‐1α (stromal cell‐derived factor 1α; 10 nmol/L, with added sitagliptin at 1 μmol/L to enhance the response) on cell number in the absence and the presence of PP1 (A; 100 ng/mL), rapamycin (B; 10 μmol/L), LY294002 (C; 10 μmol/L), and RACK1 short hairpin RNA (D) in cardiac fibroblasts (CFs) from spontaneously hypertensive rats (SHR). Each set of P values in each panel are from a 2‐factor ANOVA (factor A, level of SDF‐1α; factor B, level of indicated inhibitor). The interaction P values show that the effects of SDF‐1α were blocked by the indicated inhibitor. *,†,‡,§Significant difference (P<0.05; Fisher least significant difference test) from the first, second, third, and fourth columns, respectively. Values are means and SEM.

• 

  Figure 11. Bar graphs illustrate the effects of SDF‐1α (stromal cell‐derived factor 1α; 10 nmol/L, with added sitagliptin at 1 μmol/L to enhance the response) on cell number in the absence and the presence of pertussis toxin (A; 100 ng/mL), U73122 (B; 10 μmol/L), GF109203X (C; 10 μmol/L), and PD98059 (D; 10 μmol/L) in preglomerular vascular smooth muscle cells (PGVSMCs) from spontaneously hypertensive rats (SHR). Each set of P values in each panel are from a 2‐factor ANOVA (factor A, level of SDF‐1α; factor B, level of indicated inhibitor). The interaction P values show that the effects of SDF‐1α were blocked by the indicated inhibitor. *,†,‡,§Significant difference (P<0.05; Fisher least significant difference test) from the first, second, third, and fourth columns, respectively. Values are means and SEM.

• 

  Figure 12. Bar graphs illustrate the effects of SDF‐1α (stromal cell‐derived factor 1α; 10 nmol/L, with added sitagliptin at 1 μmol/L to enhance the response) on cell number in the absence and the presence of PP1 (A; 100 ng/mL), rapamycin (B; 10 μmol/L), and LY294002 (C; 10 μmol/L) in preglomerular vascular smooth muscle cells (PGVSMCs) from spontaneously hypertensive rats (SHR). Each set of P values in each panel are from a 2‐factor ANOVA (factor A, level of SDF‐1α; factor B, level of indicated inhibitor). The interaction P values show that the effects of SDF‐1α were blocked by the indicated inhibitor. *,†,‡,§Significant difference (P<0.05; Fisher least significant difference test) from the first, second, third, and fourth columns, respectively. Values are means and SEM.