Inhibition of keloid fibroblast proliferation by artesunate is mediated by targeting the IRE1α/XBP1 signaling pathway and decreasing TGF-ß1.

BACKGROUND: Keloid is a benign hyperplastic dermatosis with high recurrence rate and complex pathogenesis. There is no universally effective treatment yet. New therapies and elucidation of pathogenesis are urgently required. AIMS: To explore the function of IRE1α/XBP1 in keloid fibroblasts and to investigate the potential mechanism of artesunate in inhibiting keloid hyperplasia. METHODS: Human keloid fibroblasts (KFs) were cultured, and the expressions of XBP1 and TGF-ß1 were detected by immunohistochemistry. The expression of IRE1 was interfered with through cell transfection and the effects of IRE1 interference on cell proliferation and the cell cycle were assessed using MTS, colony formation assays, and flow cytometry. Detection of the expressions of XBP1 and TGF-ß1 by qRT-PCR and Western blot. Then artesunate was applied to a subset of the cells, and its effects on cell viability and the expression of related proteins using the same methods. RESULTS: The IRE1α/XBP1 pathway was activated in KFs. Knocking out the gene IRE1α can inhibit the expression of TGF-ß1, in addition, the cell viability and cell cycle progression of KFs were also significantly affected. After artesunate treatment, there was a remarkable reduction in cell proliferation. Meanwhile, the cell cycle of KFs treated with artesunate was blocked in G1 phase.After upregulating the expression of IRE1α and treating KFs with artesunate, both cell cycle and proliferation showed inhibitory effects, and related proteins also exhibited suppressed expression. CONCLUSIONS: The IRE1α/XBP1 pathway is activated in keloid, and inhibiting the expression of this pathway can affect the cell proliferation activity. In addition, artesunate also has a significant effect on fibroblast proliferation, and the IRE1α/XBP1 pathway may participate in this process. These findings suggest that IRE1α/XBP1 signal pathway may be a potential target for scar treatment, and artesunate could also be a powerful candidate for keloid treatment.

Glycogen plays a key role in survival of Salmonella Typhimurium on dry surfaces and in low-moisture foods.

Salmonella enterica is known to survive in desiccate environments and is often associated with low-moisture foods (LMFs). In this work, S. Typhimurium ATCC 14028 was found to survive better by achieving the least reductions (3.17 ± 0.20 Log CFU reduction) compared to S. Tennessee ATCC 10722 (3.82 ± 0.13 Log CFU reduction) and S. Newport ATCC 6962 (6.03 ± 0.36 Log CFU reduction) after 30 days on surfaces with a relative humidity of 49% at ambient temperature. A metabolomic analysis revealed that S. Typhimurium was still active in energy metabolism after 24 h in the desiccate environment and glycogen, an energy reserve, was drastically reduced. We followed up on the glycogen levels over 30 days and found indeed a sharp decline on the first day. However, the glycogens detected on day 7 were significantly higher (P < 0.05) and thereafter remained stable above the original levels until day 30. The expression levels of both glycogen anabolism- and catabolism-related genes (csrA, glgA, glgC, glgX) were significantly up-regulated at all tested points (P < 0.05). The glgA and glgC insertion mutants displayed weaker survivability on both dry surfaces and in representative LMFs (flour and milk powder) compared to the wild-type strain. This work highlights the role of glycogen during different periods of desiccation, which may bring novel insight into mitigating Salmonella by disrupting glycogen metabolism.

Metabolomics investigation of global responses of Cronobacter sakazakii against common sanitizing in infant formula processing environments.

Cronobacter sakazakii, an opportunistic bacterium, has raised a serious outbreak in powdered infant formula recent years. In this work, four sanitizing strategies used during infant formula processing, including chlorine, quaternary ammonium chloride (QAC), 60 °C heating, and malic acid (MA), were utilized against C. sakazakii among planktonic, air-dried (A), and air-dried & washed (AW) state, followed by an exploration of the metabolic responses induced by these treatments via a dual-platform metabolomics analysis with the ultra-high performance liquid chromatography-mass spectrometry and nuclear magnetic resonance. In the planktonic state, MA was the most effective in inhibiting bacterial growth, followed by chlorine, QAC, and 60 °C heating. Under A state, the efficacy of heating improved considerably, compared to that in the planktonic state, and remained unaltered under AW state. Chlorine and QAC were ineffective to control bacterial growth under A state, but their efficacy rose under AW state. Furthermore, the metabolomic analysis revealed chlorine induces amino acids catabolism, membrane lysis, and depression in carbohydrate and nucleotide metabolism in both planktonic and AW states, while the initiation of antioxidation mechanism was only found under AW state. Although the metabolic change caused by QAC in the planktonic state was similar to chlorine, the accumulation of osmoprotectant and membrane phospholipids within the AW cells reflected the effort to restore intracellular homeostasis upon QAC. Heating was characterized by considerable amino acid anabolism, along with mildly perturbed carbohydrate and nucleotide metabolism for heat shock protein preparation in both states. Lastly, MA promoted amino acid-dependent acid resistance under the planktonic state, and the regulation of antioxidation and osmoprotection under AW state. The metabolomics study elucidated the intracellular perturbation induced by common sanitizing, as well as the bacterial response, which provides insights for novel sanitization development.