Inhibit TGF-β1/Smad3 pathway by upregulation of miR145 with active vitamin D in lupus nephritis

Abstract

Objective To investigate whether 1,25 (OH) 2D3 inhibits the TGF-β1/Smad3 pathway through upregulation of miR145 and its possible therapeutic mechanism in lupus nephritis. Methods A total of 42 8-week-old female ApoE-/- mice were divided into 7 groups of 6 mice each. Blank control group 1 and group 2 were given 0.5 mL of sterile 0.9% saline intraperitoneally every day until the end of the experiment; blank model group 1 and group 2 were given 0.5 mL of hypocretin intraperitoneally once and fed with high-fat diet for 3 months to establish a mouse model of lupus nephritis. 1,25 (OH) 2D3 treatment group, miR145 overexpression group and miR145 empty vector group were treated with vitamin D by gavage, miR145 by gavage and miR145 by gavage, respectively. Mice were treated with vitamin D by gavage, loaded with miR145 empty vector adenovirus and loaded with miR145 overexpressing adenovirus, respectively. Urine protein level was measured by CBB at week 8 in each group, and peripheral blood ANA antibody and anti-dsDNA antibody were measured by ELISA in each group to assess the establishment of the mouse model. The expression of miR145 in peripheral blood PBMCs was measured by RT-qPCR and the expression of miR145 was observed after treatment with 1,25 (OH) 2D3. 1,25 (OH) 2D3, miR145 overexpression on the TGF-β1/Smad3 pathway. The kidneys of normal control group 1, blank model group 1, miR145 overexpression group and miR145 empty vector group were examined pathologically to compare the renal pathological changes after miR145 overexpression. Results Kidney damage was reduced in the miR145 overexpression group. Expression levels of miR145 in peripheral blood PBMCs were significantly higher than those in the miR145 empty vector group (P<0.01), and the expression of TGF-β1, Smad3 and p-smad3 were significantly lower than those in the miR145 empty vector group (P<0.01). Expression of TGF-β1, Smad3 and p-smad3 in the kidney were significantly lower than those in the miR145 empty vector group (P<0.01). 1,25 (OH) 2D3 on the treatment of lupus nephritis in mice experimental group: the amount of urinary protein in the 1,25 (OH) 2D3 treated group was significantly lower than that in the blank model group at week 24. The serum 1,25 (OH) 2D3 concentration in the 1,25 (OH) 2D3 treated group was significantly higher than that in the blank model group (P<0.01), and the expression level of miR145 in peripheral blood PBMCs was significantly higher than that in the blank model group (P<0.01), while expressions of TGF-β1, Smad3 and p-smad3 were significantly lower than those in the blank model group (all P<0.01). Conclusion 1,25 (OH) 2D3 attenuated kidney damage of lupus nephritis in mice by upregulating miR145 expression and thus negatively regulating the TGF-β1/Smad3 pathway. miR145 may be a new target for the treatment of lupus nephritis.

Keywords

• vitamin d
• lupus nephritis
• mir145
• tgf-β1/smad3 signal pathway