Effects of haem oxygenase-1 expression on oxidative injury and biological behaviours of rat dermal fibroblasts

Engineering hemin-loaded hyaluronan needle-like microparticles with photoprotective properties against UV-induced tissue damage

This study aimed to develop hyaluronan (HA)-based hydrogel microparticles (MPs) loaded with hemin to address the limitations of traditional macroscale hydrogels. The objective is to design MPs such that they can modulate their physicochemical properties. Given the widespread use of ultraviolet C (UVC) light in various industries and the need for protective measures against accidental exposure, this study evaluated the potential of hemin-loaded MPs to protect human dermal fibroblasts from oxidative stress and cell death caused by UVC exposure. Multiple MP formulations were developed and analysed for size, surface charge, swelling behaviour, degradation rate, and radical scavenging capabilities, both with and without hemin loading. The most promising formulations were tested against UVC-exposed cells to assess cell viability, intracellular nitric oxide (˙NO) and reactive oxygen species levels, and protein carbonylation. The fabricated particles were in the form of microneedles, and the degree of their crosslinking and the role of hemin in the chemical crosslinking reaction were found to influence the surface charge and hydrodynamic diameter of the MPs. Increased crosslinking resulted in reduced swelling, slower degradation, and decreased hemin release rate. MPs with a higher degree of swelling were capable of releasing hemin into the culture medium, leading to enhanced bilirubin generation in dermal fibroblasts following cellular uptake. Pre-treatment with these MPs protected the cells from UVC-induced cell death, nitrosative stress, and protein carbonylation. These findings highlight the potential of the studied MPs to release hemin and to minimise the harmful effects of UVC on dermal fibroblasts.

Oxidative Stress and Lipid Peroxidation: Prospective Associations Between Ferroptosis and Delayed Wound Healing in Diabetic Ulcers

Diabetic ulcers are one of the major complications of diabetes, and patients usually suffer from amputation and death due to delayed ulcer wound healing. Persistent inflammation and oxidative stress at the wound site are the main manifestations of delayed wound healing in diabetic ulcers. In addition, chronic hyperglycemia in patients can lead to circulatory accumulation of lipid peroxidation products and impaired iron metabolism pathways leading to the presence of multiple free irons in plasma. Ferroptosis, a newly discovered form of cell death, is characterized by intracellular iron overload and accumulation of iron-dependent lipid peroxides. These indicate that ferroptosis is one of the potential mechanisms of delayed wound healing in diabetic ulcers and will hopefully be a novel therapeutic target for delayed wound healing in diabetic patients. This review explored the pathogenesis of diabetic ulcer wound healing, reveals that oxidative stress and lipid peroxidation are common pathological mechanisms of ferroptosis and delayed wound healing in diabetic ulcers. Based on strong evidence, it is speculated that ferroptosis and diabetic ulcers are closely related, and have value of in-depth research. We attempted to clarify prospective associations between ferroptosis and diabetic ulcers in terms of GPX4, iron overload, ferroptosis inhibitors, AGEs, and HO-1, to provide new ideas for exploring the clinical treatment of diabetic ulcers.

Heme oxygenase-1 alleviates advanced glycation end product-induced oxidative stress, inflammatory response and biological behavioral disorders in rat dermal fibroblasts

Advanced glycation end products (AGEs) are involved in delaying the wound healing of diabetic foot ulcers. The present study investigated the effects of heme oxygenase-1 (HO-1) on oxidative stress, inflammatory insult and biological behaviors in rat dermal fibroblasts in the presence of AGEs. Rat dermal fibroblasts were cultured in the presence of AGEs (100 µg/ml), glucose (1.0 g/l or 4.5 g/l), hemin (5 µM) and chromium mesoporphyrin (CrMP; 20 µM). A bilirubin kit, reverse transcription-quantitative PCR and western blotting were used to measure the activity and mRNA and protein levels of HO-1, respectively. ELISA kits were used to measure the levels of reactive oxygen species (ROS), malondialdehyde (MDA), 8-hydroxydeoxyguanosine (8-OHdG), TNF-α, IL-6, IL-1β and the viability and collagen (hydroxyproline) secretion of fibroblasts. Cell proliferation and apoptosis were measured via flow cytometry. The scratch test was performed to evaluate cell migration. The results revealed that AGEs resulted in oxidative stress, inflammatory response and biological behavioral disorders in fibroblasts, while worsened functional disorders were caused by the combination of AGEs and high-glucose treatment. Hemin treatment induced sustained high HO-1 expression, decreased the levels of ROS, MDA, 8-OHdG, TNF-α, IL-6, IL-1β and cell apoptosis, and increased cellular collagen synthesis, viability, proliferation and migration, whereas CrMP abolished the effects of hemin. It was observed that high HO-1 expression reversed the AGE-induced oxidative stress, inflammatory response and biological behavioral disorders in fibroblasts, but fibroblast function did not return to that observed under normal glucose levels. In conclusion, it was demonstrated that hemin treatment induced high HO-1 expression. HO-1 reduced the AGE-induced functional disorders in fibroblasts and may accelerate the healing of diabetic wounds by improving fibroblast biological behaviors and reducing the oxidative stress and inflammatory response.

Ski promotes proliferation and inhibits apoptosis in fibroblasts under high-glucose conditions via the FoxO1 pathway

OBJECTIVES

The present study clarified the role and signalling pathway of Ski in regulating proliferation and apoptosis in fibroblasts under high-glucose (HG) conditions.

MATERIALS AND METHODS

The proliferation and apoptosis of rat primary fibroblasts were assessed using EdU incorporation and TUNEL assays. The protein and phosphorylation levels of the corresponding factors were measured using immunofluorescence staining and Western blotting. Immunoprecipitation was used to determine the interactions between Ski and FoxO1 or Ski and HDAC1. The Ski protein was overexpressed via recombinant adenovirus transfection, and FoxO1 and HDAC1 were knocked down using targeted small-interfering RNA.

RESULTS

The present study found that HG inhibited fibroblast proliferation, increased apoptosis and reduced Ski levels in rat primary fibroblasts. Conversely, increasing Ski protein levels alleviated HG-induced proliferation inhibition and apoptosis promotion. Increasing Ski protein levels also increased Ski binding to FoxO1 to decrease FoxO1 acetylation, and interfering with FoxO1 caused loss of the regulatory effect of Ski in fibroblasts under HG. Increasing Ski protein levels decreased FoxO1 acetylation via HDAC1-mediated deacetylation.

CONCLUSIONS

Therefore, these findings confirmed for the first time that Ski regulated fibroblast proliferation and apoptosis under HG conditions via the FoxO1 pathway.