Inhibition of sphingosine kinase 2 attenuates hypertrophic scar formation via upregulation of Smad7 in human hypertrophic scar fibroblasts

Abstract

The aims of the present study were to investigate the role of sphingosine kinase 2 (Sphk2) in hypertrophic scar (HS) formation and its underlying mechanisms. The expression levels of Sphk2 and Smad7 in HS tissues and healthy skin tissues of patients undergoing plastic surgery were determined using immunohistochemical staining. Subsequently, the expression levels of Sphk2 and collagen i in human embryonic skin fibroblasts (control) and human HS fibroblasts (HSF) were detected using western blot analysis and immunofluorescence assay, respectively. Following Sphk2 silencing, Smad7 overexpression or both Sphk2 and Smad7 silencing, HSF proliferative ability was assessed using cell counting Kit-8 assay and proliferation-associated proteins were evaluated using western blot analysis. in addition, the level of apoptosis in HSF was assessed using flow cytometry and expression levels of apoptotic-associated proteins were determined using western blotting. Furthermore, the expression levels of collagen i and proteins in the TGF-β1/Smad signaling pathway were detected using western blot analysis. The results indicated that the expression of Sphk2 was significantly increased, while Smad7 expression was decreased in HS tissue. Moreover, the upregulation of Sphk2 and collagen i expression levels was identified in HSF. The present results also indicated that Sphk2 silencing or Smad7 overexpression inhibited proliferation, but promoted apoptosis of HSF, coupled with changes in the expression levels of proliferation-associated proteins, with an increase in p21 and a decrease in cyclin d1 expression levels, and apoptosis-associated proteins, with an increase in Bax and cleaved caspase-3, and a decrease in Bcl-2, which were reversed following transfection with both Sphk2 and Smad7 using small interfering rna in HSF. in addition, the expression levels of transforming growth factor-β1, phosphorylated (p)-Smad2, p-Smad3 and collagen i were reduced following Sphk2 silencing or Smad7 overexpression, which were abolished by silencing both Sphk2 and Smad7. collectively, the present results indicated that inhibition of Sphk2 attenuated HS formation via upregulation of Smad7 expression, thus Sphk2 may serve as a potential therapeutic target for the treatment of HS.

miR-211-5p inhibits the proliferation, migration, invasion, and induces apoptosis of human hypertrophic scar fibroblasts by regulating TGFβR2 expression

“…It is known that CCND1 and C-myc are important factors that regulate the cell cycle and cell proliferation (29). Furthermore, Bax and Bcl-2 are key proteins that promote apoptosis and antiapoptosis, respectively (30). Also, MMP3 and MMP9, which can regulate the synthesis and degradation of ECM at the wound site, are protein factors that can regulate cell migration and invasion (31).…”

MiR-21 regulates skeletal muscle atrophy and fibrosis by targeting TGF-beta/SMAD7-SMAD2/3 signaling pathway

“…We confirmed that miR-21 could simultaneously target SMAD7 through dual-luciferase reporter assays, which is consistent with previous studies [ [41] , [42] , [43] , [44] ]. SMAD7, an inhibitor of SMAD-2/3 phosphorylation [ 45 ], is an essential negative regulator in the TGF-β1/Smad signaling pathway and inhibits fibrosis by regulating this pathway [ [46] , [47] , [48] ].…”

Altered Smooth Muscle Cell Histone Acetylome by the SPHK2/S1P Axis Promotes Pulmonary Hypertension

“…Nuclear SPHK2/S1P signaling plays a critical role in epigenetic regulation of bacterial-mediated inflammatory lung injury, 23 cardiovascular diseases, and cancer progression. 12,24 A recent study alludes to SPHK2 signaling in TGFβ1/Smad signaling pathway 36 in PH while SPHK2 phosphorylation and nuclear localization to airway epithelium suggests a critical role in epigenetic regulation of bacterial-mediated inflammatory lung injury through histone acetylation. 23 However, neither TGFβ1 nor SMAD7 were detected as a differentially acetylated region that overlaps with cCREs in CUT&RUN (data not shown).…”