Foxf2 and Smad6 co‐regulation of collagen 5A2 transcription is involved in the pathogenesis of intrauterine adhesion

Abstract

The replacement of normal endometrial epithelium by fibrotic tissue is the pathological feature of intrauterine adhesion (IUA), which is caused by trauma to the basal layer of the endometrium. COL5A2 is a molecular subtype of collagen V that regulates collagen production in fibrotic tissue. Here, we investigated the roles of Foxf2 and Smad6 in regulating the transcription of COL5A2 and their involvement in the pathogenesis of IUA. Small interference‐mediated Foxf2 (si‐Foxf2) silencing and pcDNA3.1‐mediated Smad6 (pcDNA3.1‐Smad6) up‐regulation were performed in a TGF‐β1‐induced human endometrial stromal cell line (HESC) fibrosis model. Assessment of collagen expression by Western blotting, immunofluorescence and qRT‐PCR showed that COL5A2, COL1A1 and FN were significantly down‐regulated in response to si‐Foxf2 and pcDNA3.1‐Smad6. Transfection of lentivirus vector‐Foxf2 (LV‐Foxf2) and pcDNA3.1‐Smad6 into HESCs and qRT‐PCR showed that Foxf2 promoted COL5A2 expression and Smad6 inhibited Foxf2‐induced COL5A2 expression. Co‐immunoprecipitation, chromatin immunoprecipitation and dual‐luciferase reporter assays to detect the interaction between Foxf2 and Smad6 and their role in COL5A2 transcription showed that Foxf2 interacted with Smad6 and bond the same promoter region of COL5A2. In a rat IUA model, injection of ADV2‐Foxf2‐1810 and ADV4‐Smad6 into the uterine wall showed that Foxf2 down‐regulation and Smad6 up‐regulation decreased fibrosis and the expression of COL5A2 and COL1A1, as detected by haematoxylin/eosin, Masson trichrome staining and immunohistochemistry. Taken together, these results suggested that Foxf2 interacted with Smad6 and co‐regulated COL5A2 transcription in the pathogenesis of IUA, whereas they played opposite roles in fibrosis.

The regulatory roles and mechanisms of the transcription factor FOXF2 in human diseases

“…FOXF2, also a TGF β target, cooperated with TGF β signaling to promote ECM formation. FOXF2 downregulation and SMAD6 upregulation affected the phase transition from G0/G1 to S, induced by TGF β 1 in vitro and decreased the number of endometrial fibroids encoded by COL5A2 in vivo ( Chen et al, 2020 ).…”

Focus on the Primary Prevention of Intrauterine Adhesions: Current Concept and Vision

“…IUA presents a challenge to the endometrial model of scar-free wound healing, as it would appear that several postulated mechanisms that allow for scar-free regeneration and repair are lost, including hypoxic injury, unbalanced inflammatory processes, decreased angiogenesis, the disturbance of immune and molecular mechanisms, an unregulated EMT, aberrant myofibroblast differentiation, bizarre stem cell regeneration, and interrupted normal endometrial cell proliferation [ 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 ]. However, evidence has shown the presence of distinct genetic profiles between patients with and without IUA, suggesting that IUA might not just be a representative of an iatrogenic disease, but also the result of a genetic predisposition [ 72 ].…”

“…Many strategies or principles for decreasing the risk of developing IUA, such as the reduced use of electrosurgery and the minimization of trauma to the healthy endometrium and myometrium, have been proposed [ 73 , 74 , 75 , 76 , 77 , 78 , 79 ]. Additionally, many biomaterial agents, barrier methods, and cell or bio-agent therapies have been applied [ 14 , 16 , 24 , 27 , 28 , 29 , 30 , 31 , 35 , 37 , 40 , 43 , 44 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 ]. Figure 3 shows the recent development of agents available for the primary prevention of IUA after uterine surgery.…”

“…One involves the avoidance of over- or purulent inflammatory processes or over-traumatic injury; the second is a barrier method to prevent the attachment of the bilateral traumatic surface; the third is the enhancement of regeneration ability; the last is early intervention via repeat hysteroscopy to remove the thin or immature adhesion band ( Figure 3 ). The tools include agents (drugs) or physical (mechanical) barriers to cover the uterine lining side, or separate the opposing sides of the uterine linings immediately after hysteroscopic surgery; the prescription of estrogen use postoperatively, postoperative gonadotropin-releasing hormone agonist injection, or immediate postoperative antibiotics use; and the use of biomaterials or new technologies such as cellular therapy [ 5 , 6 , 7 , 8 , 9 , 10 , 14 , 23 , 24 , 27 , 28 , 29 , 30 , 31 , 32 , 35 , 36 , 37 , 39 , 40 , 41 , 42 , 43 , 56 , 57 , 58 , 59 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 86 , 101 , 102 , 103 , 104 , 105 , 106 , 107 , …”

Recent developments in bio-scaffold materials as delivery strategies for therapeutics for endometrium regeneration

“…Dilatation and curettage (D&C), a primary risk factor for IUA, causes damage to the basal layer of the endometrium, thereby leading to endometrial fibrosis, in which fibrous tissues replace stromal tissues and is accompanied by a decrease in or disappearance of glands. As a result, the uterine cavity and/or the cervical canal become partially or completely obliterated [ 3 ]. According to reports, 36–53 million pregnancies worldwide are terminated yearly, of which approximately 90% occur in the first trimester [ 4 ].…”