PTX3 in serum induces renal mesangial cell proliferation but has no effect on apoptosis

Abstract

The present study aimed to investigate the effect of pentraxin 3 (PTX3) on the regulation of proliferation and apoptosis in human glomerular mesangial cells (HMCs). Small interfering (si)RNA was designed and synthesized to inhibit the expression of endogenous PTX3, and the effects on the proliferation and apoptosis of HMCs were detected by flow cytometry and an MTT assay. Western blot analysis was used to detect the activation of mitogen-activated protein kinase (MAPK) proteins in HMCs with PTX3 knockdown. Three siRNAs targeting PTX3 were individually transfected into HMCs for 48 h, and reverse-transcription quantitative PCR demonstrated that the relative mRNA expression of PTX3 was significantly decreased in all groups by up to 79.62% of that in the control group (P<0.05). Following transfection with PTX3-siRNA, the viability of an HMC line was significantly decreased in comparison with that of a control group transfected with scrambled siRNA. However, PTX3-siRNA did not significantly effect early and late apoptotic cell populations in HMCs compared with those in the control. Endogenous PTX3 interference was found to significantly decrease p38 MAPK, extracellular signal-regulated kinase 1/2 and c-Jun N-terminal kinase phosphorylation. In conclusion, silencing of PTX3, inhibited the proliferation of HMCs via MAPK pathways, but exerted no effect on the apoptosis of HMCs.

Keywords: apoptosis; glomerular mesangial cells; pentraxin 3; proliferation.

Figure 1.

siPTX3 significantly reduced the expression of PTX3 mRNA in human glomerular mesangial cells. **P<0.01 vs. Scramble. PTX3, pentraxin 3; siPTX3, small interfering RNA targeting PTX3.

Figure 2.

Human glomerular mesangial cell proliferation in Scramble, siPTX3-1, siPTX3-2 and siPTX3-3 groups. OD450, optical density at 450 nm; siPTX3, small interfering RNA targeting pentraxin 3. *P<0.05 vs. siPTX3-1, −2 and −3.

Figure 3.

siPTX3 had no significant effect on the apoptosis of human glomerular mesangial cells. siPTX3, small interfering RNA targeting pentraxin 3; FITC, fluorescein isothiocyanate; PI, propidium iodide.

Figure 4.

Protein levels of p38 MAPK, JNK and ERK1/2 as well as their phosphorylated forms in human glomerular mesangial cells. Phosphorylation of p38 MAPK, JNK and ERK1/2 were significantly reduced after knockdown of PTX3. *P<0.05, **P<0.01 vs. Scramble. MAPK, mitogen-activated protein kinase; p-ERK, phosphorylated extracellular signal-regulated kinase; JNK, c-Jun N-terminal kinase; PTX3, pentraxin 3; siPTX3, small interfering RNA targeting PTX3.