Relaxin stimulates MMP-2 and α-smooth muscle actin expression by human periodontal ligament cells

Relaxin Enhances the Collagenolytic Activity and In Vitro Invasiveness by Upregulating Matrix Metalloproteinases in Human Thyroid Carcinoma Cells

“…RLN affects the expression and/or secretion of collagenase 1 (MMP1) and 3 (MMP13), gelatinase A (MMP2) and B (MMP9), stromelysin1 (MMP3), and MT1-MMP in the periodontal apparatus and joints (38)(39)(40), lung (13), reproductive tissues (24,(41)(42)(43), human renal fibroblasts (44), and human breast cancer cells (20). We previously showed that human thyroid cancer tissue is a source of RLN2 and that RLN2 enhances elastin matrix degradation by thyroid cancer cells (7).…”

Role of Mechanical Stress-induced Glutamate Signaling-associated Molecules in Cytodifferentiation of Periodontal Ligament Cells

“…Interestingly, de Araujo et al (33) reported a microarray analysis of human PDL cells under compressive forces using an in vitro three-dimensional culture system. They identified several up-regulated genes, including inflammation-related molecules, such as COX-2 (cyclooxygenase-2), PGE 2 (prostaglandin E 2 ), IL-6 (interleukin-6), and IL-1␤ (interleukin-1␤), which were not listed in our present study. These findings suggest that mechanical compressive stress tends to induce inflammation and destructive responses, whereas tensile stress induces cytodifferentiation and remodeling responses in PDL cells in vivo, similar to those in orthodontic treatments.…”

“…The periodontal ligament (PDL) 3 is a connective tissue interposed between the roots of teeth and the inner wall of the tooth-supporting bone (alveolar bone) socket. The PDL constitutively and iatrogenically receives mechanical stress, such as occlusal pressure and orthodontic forces, which have effects on the homeostasis of the PDL (2). Proper mechanical stress on teeth induces not only the proliferation and differentiation of PDL cells into osteoblasts and cementoblasts but also the synthesis and degradation of extracellular matrix (ECM) molecules (3).…”

Upregulation of relaxin receptors in the PDL by biophysical force

“…Subtle differences in cellular response to Rln treatment existed according to the cell state, that is, between being tensed or compressed. These differences may partly explain the discrepant results between the in vitro and in vivo studies for the use of Rln in orthodontic tooth movement [10][11][12][13][14][15]. However, extrapolating from the failure to demonstrate Rln-enhanced orthodontic tooth movement, any conclusion as to its usefulness in orthodontic treatment should be approached with caution, as suggested by Madan [14].…”

“…Rln is a good candidate molecule for biological approaches, considering its effects on connective tissue turnover and bone cells. Specifically, Rln modulates in vitro PDL cells, which are crucial for periodontal remodeling through the stimulation of matrix metalloproteinase (MMP)-2 and α-actin expression [10] or Col-1 and MMP-1 expression [11]. Although Rln was found to be effective in preventing relapse after experimental tooth movement in rats [12], the in vivo effects of Rln on orthodontic tooth movement require further research.…”