Wound healing involves the collaboration of multiple cells, including macrophages and fibroblasts, and requires the coordination of cytokines, growth factors, and matrix proteins to regulate the repair response. In this study, we investigated how M2 macrophages regulate expression of the anti-fibrotic and anti-inflammatory regulator tumor necrosis factor-α (TNF-α)-stimulated gene 6 (TSG-6) secreted by adipose tissue-derived stem cells (ASCs) during wound healing. Interleukin (IL)-4/IL-13, which is used to differentiate macrophage M2 phenotypes, increases TSG-6 in ASCs; however, M2 macrophages significantly decrease TSG-6 in ASCs. Transforming growth factor (TGF)-β expression was increased, and TNF-α expression was decreased in M2 macrophages. TGF-β inhibited IL-4/IL-13-induced ASC TSG-6 expression. In addition, TSG-6 suppressed TGF-β-triggered wound closure and fibrogenic responses in LX-2 cells. Collectively, TSG-6 inhibited wound healing, but M2 macrophage-expressed TGF-β prevented TSG-6 production from ASCs, which ultimately helped wound healing. Our results indicate that the balance of TNF-α and TGF-β levels during wound healing regulates TSG-6 production from ASCs, which may ultimately modulate the healing process. Our study findings could contribute to novel therapeutic strategies that manipulate the delicate balance between TNF-α and TGF-β to enhance wound repair and mitigate fibrosis.

Enterotoxigenic Bacteroides fragilis (ETBF) is an intestinal bacterium that secretes the metalloprotease Bacteroides fragilis toxin (BFT), which induces E-cadherin cleavage and interleukin-8 secretion in human intestinal epithelial cell lines. ETBF-induced E-cadherin cleavage is proposed to be the underlying reason for the promotion of colitis in ETBF-infected mice. However, a BFT-responsive murine cell line has not yet been reported. In the current study, we report that the mouse colonic epithelial cell line CMT93 undergoes E-cadherin ectodomain cleavage, cell rounding, and proliferation in response to BFT treatment. The amino acid sequence of the putative cleavage site of E-cadherin is identical in both BFT-responsive (CMT93) and BFT-nonresponsive (MSIE, CT26, YAMC, and B16) cell lines, suggesting that the E-cadherin amino acid sequence is not responsible for this observation. After E-cadherin ectodomain cleavage, the membrane-bound intracellular E-cadherin domain underwent cleavage by γ-secretase and was subsequently degraded by the proteasome. Moreover, BFT induced the secretion of two chemokines (LIX and KC) and the formation of soluble TNFR1 in the CMT93 cell line. The identification of a BFT-responsive murine cell line may be used to elucidate the mechanism of ETBF pathogenesis in ETBF murine infection models.

Background/Aim: Over-expression of apurinic/apyrimidinic endonuclease 1 (APE1) has been demonstrated to be associated with cancer progression, chemo- and radioresistance in various cancers. This study examined the expression of APE1 and its relation to tumor progression and prognosis in patients with colorectal cancer (CRC). Materials and Methods: We investigated 193 patients with CRC who received curative surgery for whom formalin-fixed and paraffin-embedded blocks were available, and long-term tumor-specific survival rate analysis was possible. The expression of APE1 was investigated by reverse transcription-polymerase chain reaction, western blotting, and immunohistochemistry in CRC and lymph node tissues. The apoptosis, proliferation, and angiogenesis of CRC cells were determined using terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay, and immunohistochemical staining for Ki-67 and CD34 antibodies. Results: APE1 was over-expressed in CRC and metastatic lymph node tissues compared with normal colorectal mucosa and non-metastatic lymph node tissues. Over-expression of APE1 was significantly associated with advanced stage, lymphovascular invasion, perineural invasion, deeper tumor invasion, lymph node metastasis, distant metastasis, and poor survival. Multivariate analysis demonstrated that APE1, perineural invasion, and lymph node metastasis were the independent prognostic factors associated with overall survival. The mean Ki-67 labeling index value of APE1-positive tumors was significantly higher than that of APE1-negative tumors. However, there was no significant association between APE1 expression and the apoptotic index or microvessel density. Conclusion: Over-expression of APE1 is significantly associated with tumor progression and poor survival in patients with CRC. Therefore, APE1 may be a novel biomarker and present a potential prognostic factor for CRC.

Pressure ulcers (PUs) are localized injuries caused by prolonged mechanical loading and ischemia, often leading to delayed healing and high recurrence rates. Although conventional treatments aim to support tissue repair, their efficacy remains limited, prompting interest in noninvasive therapies such as the pulsed electromagnetic field (PEMF). The PEMF has been reported to enhance cellular proliferation, re-epithelialization, and collagen remodeling, but its effects in pressure ulcer models, particularly concerning genetic background, remain unclear. This study investigated the therapeutic effects of the PEMF in a murine pressure ulcer model established by ischemia and reperfusion injury induced with externally attached magnets in two mouse strains, BALB/c and C57BL/6. The PEMF (10 Hz, 24 h per day) was used to treat PU-induced mice from day 4 to day 15 in BALB/c mice and to day 14 in C57BL/6 mice. Wound healing was assessed by gross morphological observation, histological analysis, and digital quantification of epidermal lesion length and collagen-positive area. In BALB/c mice, PEMF-treated wounds showed a modest trend toward improved re-epithelialization and collagen deposition, although the differences were not statistically significant. In contrast, C57BL/6 mice exhibited a significantly shorter length of epidermal lesion in the PEMF group on day 14, indicating enhanced epidermal regeneration. Collagen analysis showed comparable levels between treated and control groups in both strains, with no significant differences observed. To further assess the cellular response to PEMF, a scratch wound assay was conducted using HaCaT cells. Quantitative analysis demonstrated that PEMF treatment accelerated cell migration and wound closure in vitro. These findings suggest that PEMF enhances epidermal regeneration and keratinocyte mobility, with therapeutic responses potentially influenced by genetic background. This study supports the potential application of PEMF in pressure ulcer treatment and underscores the importance of strain selection in preclinical wound healing research.

Wound healing involves the collaboration of multiple cells, including macrophages and fibroblasts, and requires the coordination of cytokines, growth factors, and matrix proteins to regulate the repair response. In this study, we investigated how M2 macrophages regulate expression of the anti-fibrotic and anti-inflammatory regulator tumor necrosis factor-α (TNF-α)-stimulated gene 6 (TSG-6) secreted by adipose tissue-derived stem cells (ASCs) during wound healing. Interleukin (IL)-4/IL-13, which is used to differentiate macrophage M2 phenotypes, increases TSG-6 in ASCs; however, M2 macrophages significantly decrease TSG-6 in ASCs. Transforming growth factor (TGF)-β expression was increased, and TNF-α expression was decreased in M2 macrophages. TGF-β inhibited IL-4/IL-13-induced ASC TSG-6 expression. In addition, TSG-6 suppressed TGF-β-triggered wound closure and fibrogenic responses in LX-2 cells. Collectively, TSG-6 inhibited wound healing, but M2 macrophage-expressed TGF-β prevented TSG-6 production from ASCs, which ultimately helped wound healing. Our results indicate that the balance of TNF-α and TGF-β levels during wound healing regulates TSG-6 production from ASCs, which may ultimately modulate the healing process. Our study findings could contribute to novel therapeutic strategies that manipulate the delicate balance between TNF-α and TGF-β to enhance wound repair and mitigate fibrosis.

Jiyun HONG, Ki-Jong RHEE. Korean J Clin Lab Sci. 2025;57:1-15. https://doi.org/10.15324/kjcls.2025.57.1.1