Abstract: FR-PO235

APOL1-microRNA193a Feedback Loop Facilitates Monocyte Macrophage Transition

Session Information

Category: Cell Biology

  • 202 Apoptosis, Proliferation, Autophagy, Cell Senescence, Cell Transformation

Authors

  • Kumar, Vinod, The Feinstein Institute for Medical Research, Manhasset, New York, United States
  • Lan, Xiqian, Feinstein Institute for Medical Research, Great Neck, New York, United States
  • Marashi Shoshtari, Seyedeh Shadafarin, The Feinstein Institute for Medical Research, Manhasset, New York, United States
  • Chowdhary, Sheetal, Feinstein Institute of Medical Research, New Hyde Park, New York, United States
  • Bhooplapur, Manali, Feinstein Institute for medical research, Dix Hills, New York, United States
  • Malhotra, Ashwani, Feinstein Inst.Med research and NSLIJ, Manhasset, New York, United States
  • Skorecki, Karl, Rambam Health Care Campus, Haifa, Israel
  • Singhal, Pravin C., North Shore LIJ Health System, Great Neck, New York, United States
Background

Macrophage influx in the mesangium has been considered to be a precursor of mesangial expansion, a feature of focal segmental glomerulosclerosis. APOL1 is expressed by macrophages but not by monocytes. Therefore, APOL1 expression is associated with monocyte transition. However, the role of APOL1 in the conversion of monocytes to macrophages (transition) has not been investigated to date. We have studied feedback loop relationship between APOL1 and microRNA193a in parietal epithelial cells (abstract submitted to ASN). We now hypothesize that APOL1-microRNA (miR)-193a feedback loop facilitates monocyte macrophage transition.

Methods

Peripheral blood mononuclear cells (PBMCs) were harvested and incubated in media containing either buffer or experimental agents including, PMA (100 ng/ml), vitamin D receptor (VDR) agonist (EB1089, 50 nM), IFN-y (10 nM), HIV (NL4-3, 100 GEU units X1000), and LPS (10 ng/ml) for adherence for 48 hours followed by assays for adherence and expression of APOL1 mRNA and protein. To examine a causal relationship APOL1 and miR193a, control human monocytes (THPs) were transfected with control and APOL1 siRNAs and incubated in media containing either buffer or PMA, VDR agonist, IFN-y, HIV, and LPS for 48 hours, followed by assays for adherence and miR193a. To confirm the role of feedback loop relationship, THPs were transfected with either control or miR193a plasmids followed treatment with PMA or VDA for 48 hours and assay for APOL1 expression.

Results

Experimental agents enhanced (PMA, 50 fold, VDA, 10 fold, IFN-y 15 fold, HIV 10 fold, and LPS 15 fold) adherence when compared to control PBMCs. All experimental agents induced protein expression of APOL1 in THPs and PBMCs. However, knockout of APOL1 in THPs partially inhibited (<0.01) adherence of PBMCs and THPs treated with PMA (90%), VDA (80%), IFN-y (90%), and LPS (80%). Experimental agents down regulated (P<0.01) THPs expression of miR193a whereas knockout APOL1 reversed this effect of experimental agents on THPs expression of miR193a. However, overexpression of miR193a inhibited PMA/VDA –induced expression of APOL1 in THPs.

Conclusion

These findings suggest that APOL1 through mi193a feedback loop facilitates monocyte macrophage transition

Funding

  • NIDDK Support