BACKGROUND
Bone marrow-derived mesenchymal stem cells (MSCs) show podocyte-protective effects in chronic kidney disease. Calycosin (CA), a phytoestrogen, is isolated from
Astragalus membranaceus
with a kidney-tonifying effect. CA preconditioning enhances the protective effect of MSCs against renal fibrosis in mice with unilateral ureteral occlusion. However, the protective effect and underlying mechanism of CA-pretreated MSCs (MSCs
CA
) on podocytes in adriamycin (ADR)-induced focal segmental glomerulosclerosis (FSGS) mice remain unclear.
AIM
To investigate whether CA enhances the role of MSCs in protecting against podocyte injury induced by ADR and the possible mechanism involved.
METHODS
ADR was used to induce FSGS in mice, and MSCs, CA, or MSCs
CA
were administered to mice. Their protective effect and possible mechanism of action on podocytes were observed by Western blot, immunohistochemistry, immunofluorescence, and real-time polymerase chain reaction.
In vitro
, ADR was used to stimulate mouse podocytes (MPC5) to induce injury, and the supernatants from MSC-, CA-, or MSCs
CA
-treated cells were collected to observe their protective effects on podocytes. Subsequently, the apoptosis of podocytes was detected
in vivo
and
in vitro
by Western blot, TUNEL assay, and immunofluorescence. Overexpression of Smad3, which is involved in apoptosis, was then induced to evaluate whether the MSCs
CA
-mediated podocyte protective effect is associated with Smad3 inhibition in MPC5 cells.
RESULTS
CA-pretreated MSCs enhanced the protective effect of MSCs against podocyte injury and the ability to inhibit podocyte apoptosis in ADR-induced FSGS mice and MPC5 cells. Expression of p-Smad3 was upregulated in mice with ADR-induced FSGS and MPC5 cells, which was reversed by MSC
CA
treatment more significantly than by MSCs or CA alone. When Smad3 was overexpressed in MPC5 cells, MSCs
CA
could not fulfill their potential to inhibit podocyte apoptosis.
CONCLUSION
MSCs
CA
enhance the protection of MSCs against ADR-induced podocyte apoptosis. The underlying mechanism may be related to MSCs
CA
-targeted inhibition of p-Smad3 in podocytes.