A Modified Collagen Dressing Induces Transition of Inflammatory to Reparative Phenotype of Wound Macrophages

Abstract

Collagen containing wound-care dressings are extensively used. However, the mechanism of action of these dressings remain unclear. Earlier studies utilizing a modified collagen gel (MCG) dressing demonstrated improved vascularization of ischemic wounds and better healing outcomes. Wound macrophages are pivotal in facilitating wound angiogenesis and timely healing. The current study was designed to investigate the effect of MCG on wound macrophage phenotype and function. MCG augmented recruitment of macrophage at the wound-site, attenuated pro-inflammatory and promoted anti-inflammatory macrophage polarization. Additionally, MCG increased anti-inflammatory IL-10, IL-4 and pro-angiogenic VEGF production, indicating a direct role of MCG in resolving wound inflammation and improving angiogenesis. At the wound-site, impairment in clearance of apoptotic cell bioburden enables chronic inflammation. Engulfment of apoptotic cells by macrophages (efferocytosis) resolves inflammation via a miR-21-PDCD4-IL-10 pathway. MCG-treated wound macrophages exhibited a significantly bolstered efferocytosis index. Such favorable outcome significantly induced miR-21 expression. MCG-mediated IL-10 production was dampened under conditions of miR-21 knockdown pointing towards miR-21 as a causative factor. Pharmacological inhibition of JNK attenuated IL-10 production by MCG, implicating miR-21-JNK pathway in MCG-mediated IL-10 production by macrophages. This work provides direct evidence demonstrating that a collagen-based wound-care dressing may influence wound macrophage function and therefore modify wound inflammation outcomes.

Urolithin A augments angiogenic pathways in skeletal muscle by bolstering NAD+ and SIRT1

“…(G) mRNA expression of Cyr61 was measured by quantitative PCR in C2C12 cells treated with UA (10 µg/ml) and SIRT1 inhibitor, EX527 (50 nM) for 24 h. Data presented as mean ± SEM (n = 5); *p < 0.05 compared to placebo; † p < 0.05 as compared to UA. [67][68][69][70] . Fluorescent images were collected using AxioScan (Zeiss, Germany; for IHC) and confocal microscopy (LSM880, Zeiss, Germany; for ICC).…”

A surfactant polymer wound dressing protects human keratinocytes from inducible necroptosis

“…Subsequently, the pellets were mixed in a 200 µL of PI (10 µg/ml, diluted in 4% FBS) and incubated at room temperature for 15 min. The flow cytometry measurements were performed using the BD Accuri flow cytometry (BD Biosciences, USA) and analyzed as previously described 100 , 101 .…”

“…Cells were grown and treated in the 8-well chamber slides (Thermo Scientific Nunc Lab-Tek, Waltham, MA, # 12-565-22). The attached cells were washed with DPBS and were subjected to immunocytochemistry as previously described 3 , 37 , 100 , 101 , 102 . Subsequently, cells were fixed with intracellular (IC) fixation buffer (eBioscience, San Diego, CA, # 00-8222-49) followed by the permeabilization using 0.1% Triton X-100 3 , 37 , 100 , 101 , 102 .…”

“…The attached cells were washed with DPBS and were subjected to immunocytochemistry as previously described 3 , 37 , 100 , 101 , 102 . Subsequently, cells were fixed with intracellular (IC) fixation buffer (eBioscience, San Diego, CA, # 00-8222-49) followed by the permeabilization using 0.1% Triton X-100 3 , 37 , 100 , 101 , 102 . The cells were incubated with 10% normal goat serum (NGS, Vector Labs, Inc, Burlingame, CA, # S-1000) for 1 h at room temperature for blocking non-specific binding of antibodies 3 , 37 , 100 , 101 , 102 .…”

Advances in the Research of Bioinks Based on Natural Collagen, Polysaccharide and Their Derivatives for Skin 3D Bioprinting

“…It is the most abundant protein in mammals including humans, possessing different cell binding sequences such as Arg-Gly-Asp (RGD) and Gly-Phe-Hyp-Gly-Glu-Arg (GFOGER) that influence adhesion of fibroblasts to the scaffold [ 95 , 96 ]. Collagen based scaffold has also been reported to influence the cellular functions of fibroblasts and keratinocytes, including cell shape, differentiation and migration due to the presence of RGD and GFOGER sequences [ 97 ]. It also helps in synthesizing a number of skin ECM proteins to enhance the skin regeneration process.…”