Olfactomedin-4 improves cutaneous wound healing by promoting skin cell proliferation and migration through POU5F1/OCT4 and ESR1 signalling cascades

The Role of Crosstalk between Nets and Keratinocytes in Skin Immunity

The skin is the principal barrier against pathogens. Skin-resident cells, especially keratinocytes, play essential roles in skin immunity. Damage to the integrity of the skin barrier triggers the localized release of proinflammatory factors from keratinocytes, which attract neutrophils. These infiltrating neutrophils in turn release cytokines to modulate keratinocyte function, thereby amplifying skin inflammation. In addition, neutrophils produce neutrophil extracellular traps in a process called NETosis. Notably, crosstalk between neutrophils and keratinocytes is a prominent feature of skin infection eradication and autoimmune disorder development. In this paper, we review research progress on neutrophil extracellular traps in cutaneous immunity, with a particular emphasis on their modulation of keratinocytes. Moreover, we discuss the implications of neutrophil heterogeneity for immune defense and disease development and treatment.

Forkhead box A1 induces angiogenesis through activation of the S100A8/p38 MAPK axis in cutaneous wound healing

BACKGROUND

The association between S100 calcium-binding protein A8 (S100A8) and angiogenesis has been reported in previous reports. This study focuses on the roles of S100A8 in the angiogenesis of human dermal microvascular endothelial cells (HDMECs) and in cutaneous wound healing in mice.

METHODS

Candidate genes related to angiogenesis activity were screened using a GSE83582 dataset. The overexpression DNA plasmid of S100A8 was transfected into HDMECs to analyze its effect on cell proliferation, migration, and angiogenesis. Full-thickness skin wounds were induced on mice, followed by adenovirus treatments to analyze the function of gene alteration in wound healing and pathological changes. The upstream regulator of S100A8 was predicted by bioinformatics analysis and verified by luciferase and immunoprecipitation assays. The role of the forkhead box A1 (FOXA1)-S100A8 interaction in p38 MAPK activation and angiogenesis were validated by rescue experiments.

RESULTS

S100A8 was identified as a gene significantly correlated with angiogenesis. The S100A8 upregulation promoted the proliferation, migration, and angiogenesis of HDMECs, and it promoted p38 MAPK phosphorylation. Treatment of SB203580, a p38 MAPK inhibitor, blocked the promoting effect of S100A8. FOXA1 was identified as an upstream factor of S100A8 promoting its transcription. FOXA1 overexpression in HDMECs increased p38 MAPK phosphorylation and enhanced the activity of cells, which were blocked by the S100A8 inhibition. Similar results were reproduced in vivo where FOXA1 overexpression accelerated whereas the S100A8 knockdown retarded the cutaneous wound healing in mice.

CONCLUSION

FOXA1 mediates the phosphorylation of p38 MAPK through transcription activation of S100A8, thereby inducing angiogenesis and promoting cutaneous wound healing.

The Prediction of Antioxidant Q-Markers for Angelica dahurica Based on the Dynamics Change in Chemical Compositions and Network Pharmacology

OBJECTIVE

To clarify the accumulation and mutual transformation patterns of the chemical components in Angelica dahurica (A. dahurica) and predict the quality markers (Q-Markers) of its antioxidant activity.

METHOD

The types of and content changes in the chemical components in various parts of A. dahurica during different periods were analyzed by using gas chromatography-mass spectrometry technology (GC-MS). The antioxidant effect of the Q-Markers was predicted using network pharmacological networks, and molecular docking was used to verify the biological activity of the Q-Markers.

RESULT

The differences in the content changes in the coumarin compounds in different parts were found by using GC-MS technology, with the relative content being the best in the root, followed by the leaves, and the least in the stems. The common components were used as potential Q-Markers for a network pharmacology analysis. The component-target-pathway-disease network was constructed. In the molecular docking, the Q-Markers had a good binding ability with the core target, reflecting better biological activity.

CONCLUSIONS

The accumulation and mutual transformation patterns of the chemical components in different parts of A. dahurica were clarified. The predicted Q-Markers lay a material foundation for the establishment of quality standards and a quality evaluation.

Stimulation with THBS4 activates pathways that regulate proliferation, migration and inflammation in primary human keratinocytes

As in other mammalian tissues, the extracellular matrix (ECM) of skin functions as mechanical support and regulative environment that guides the behavior of the cells. ECM is a gel-like structure that is primarily composed of structural and nonstructural proteins. While the content of structural proteins is stable, the level of nonstructural ECM proteins, such as thrombospondin-4 (THBS4), is dynamically regulated. In a previous work we demonstrated that THBS4 stimulated cutaneous wound healing. In this work we discovered that in addition to proliferation, THBS4 stimulated the migration of primary keratinocytes in 3D. By using a proteotransciptomic approach we found that stimulation of keratinocytes with THBS4 regulated the activity of signaling pathways linked to proliferation, migration, inflammation and differentiation. Interestingly, some of the regulated genes (eg IL37, TSLP) have been associated with the pathogenesis of atopic dermatitis (AD). We concluded that THBS4 is a promising candidate for novel wound healing therapies and suggest that there is a potential convergence of pathways that stimulate cutaneous wound healing with those active in the pathogenesis of inflammatory skin diseases.

Matricellular proteins in cutaneous wound healing

Cutaneous wound healing is a complex process that encompasses alterations in all aspects of the skin including the extracellular matrix (ECM). ECM consist of large structural proteins such as collagens and elastin as well as smaller proteins with mainly regulative properties called matricellular proteins. Matricellular proteins bind to structural proteins and their functions include but are not limited to interaction with cell surface receptors, cytokines, or protease and evoking a cellular response. The signaling initiated by matricellular proteins modulates differentiation and proliferation of cells having an impact on the tissue regeneration. In this review we give an overview of the matricellular proteins that have been found to be involved in cutaneous wound healing and summarize the information known to date about their functions in this process.

Olfactomedin 4 regulates migration and proliferation of immortalized non-transformed keratinocytes through modulation of the cell cycle machinery and actin cytoskeleton remodelling

Olfactomedin 4 (OLFM4), a multifunctional matricellular protein, is involved in regulation of angiogenesis, innate immunity, inflammation, tumorigenesis and metastasis formation via modulation of important cellular processes like adhesion, proliferation, differentiation as well as apoptosis. In our previous work we demonstrated the upregulation of OLFM4 during liver regeneration and cutaneous wound healing. Here we studied the outcomes of OLFM4 downregulation in human immortalized keratinocytes - the HaCaT cells. The suppression of OLFM4 inhibited migration but enhanced the proliferation of these cells. By using proteomic, and phosphoproteomic analysis, we found that OLFM4 downregulation induced changes in the levels of 184 proteins and 348 phosphosites. An integrated pathway analysis suggested that the increased phosphorylation of CDK7 at Ser164 and Thr170 may serve as the key event in the activation of CDK2 and consequent activation of cell cycle progression. Furthermore, the decrease in GIT1 and WAVE2 protein levels were connected to the disorganization of the actin cytoskeleton, reduction of lamellipodia formation at the leading edge of HaCaT cells, and decrease in their migration capacity.