Acceleration of Collagen Breakdown by Extracellular Basic pH in Human Dermal Fibroblasts

Abstract

Background/Aims: Wound healing is a complex regeneration process involving the degradation and reassembly of connective tissues and skin layers. Previous studies have shown that pH plays a significant role in both the direct and indirect regulation of cellular processes in the wound, which, in turn, affect the wound healing process. However, the effects of pH on the collagen breakdown component of wound healing have yet to be investigated. Therefore, we investigated the induction of accelerated collagen breakdown by pH imbalance in the skin. Methods: Na⁺/H⁺ exchanger and metalloproteinase (MMP)-1 were analyzed spectrophotometrically, and the expression of collagen type-I-alpha-1 (COL1A1) and mitogen-activated protein kinase (MAPK) was measured by Western blotting. Results: Accelerated collagen breakdown induced by extracellular basic pH via the overproduction of reactive oxygen species (ROS) and MAPK signaling was examined in skin fibroblasts and in a three-dimensional human skin equivalent system. Basic pH (>7.50) upregulated MMP-1 and downregulated COL1A1 levels via ROS generation and MAPK signaling pathways. Acidic pH (<6.04) slightly upregulated MMP-1 and slightly downregulated COL1A1 levels via ROS generation and the p38 signaling pathway. Conclusion: Our results indicate that skin pH is an important effector of collagen formation in wound healing. This finding will aid in the development of new pH-targeted therapeutic strategies.

Acidic pH derived from cancer cells as a double‐edged knife modulates wound healing through DNA repair genes and autophagy

“…The signal transduction pathway that leads to acidic extracellular‐induced MMP9 overexpression is through the activation of phospholipase D and phosphorylation of p38 and MAPK1/2. Park et al showed that cell treatment at pHs 6.04‐6.48 and 7.64‐7.99 leads to MMP‐1 and p38 gene expressions and ROS production . Our data also showed an enhancement of ROS production in face to acidic media.…”

Acceleration of Apoptosis by Extracellular Basic pH in a 3D Human Skin Equivalent System

“…Similarly, our previous study showed that mitogen-activated protein kinase signaling and ROS generation were significantly increased by pH values >7.64 in human fibroblast skin cells or 3HSE [6]. In addition, human fibroblast HS68 cells responded to increased pH toxicity by inducing NADH dehydrogenase activity [6]. To assess whether basic pH increases apoptosis, we measured Annexin V levels.…”

“…The 3HSE was established according to previously published methods [6]. Using Neoderm®-ED purchased from TEGO Science (Seoul, South Korea), human dermal fibroblasts (HDF) were cultured in collagen matrix for 1 day.…”

“…The skin equivalent was then treated with pH 6.40-7.70 for 10 days and the medium was changed every 2 days for 10 days. The skin equivalent was incubated at 37°C under 5% CO 2 and the cell culture system was then established according to previously published methods [6]. The HaCaT human epidermal keratinocyte cell line was donated by Dr. HS Lim at KIOM, Korea [6].…”

“…The skin equivalent was incubated at 37°C under 5% CO 2 and the cell culture system was then established according to previously published methods [6]. The HaCaT human epidermal keratinocyte cell line was donated by Dr. HS Lim at KIOM, Korea [6]. Cells were maintained in DMEM supplemented with 10% heat inactivated FBS and 1% penicillin/streptomycin under an atmosphere of 95% air and 5% CO 2 at 37°C.…”